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Commit 7f3591cf authored by Linus Torvalds's avatar Linus Torvalds
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Merge git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-lguest 

* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-lguest: (31 commits)
  lguest: add support for indirect ring entries
  lguest: suppress notifications in example Launcher
  lguest: try to batch interrupts on network receive
  lguest: avoid sending interrupts to Guest when no activity occurs.
  lguest: implement deferred interrupts in example Launcher
  lguest: remove obsolete LHREQ_BREAK call
  lguest: have example Launcher service all devices in separate threads
  lguest: use eventfds for device notification
  eventfd: export eventfd_signal and eventfd_fget for lguest
  lguest: allow any process to send interrupts
  lguest: PAE fixes
  lguest: PAE support
  lguest: Add support for kvm_hypercall4()
  lguest: replace hypercall name LHCALL_SET_PMD with LHCALL_SET_PGD
  lguest: use native_set_* macros, which properly handle 64-bit entries when PAE is activated
  lguest: map switcher with executable page table entries
  lguest: fix writev returning short on console output
  lguest: clean up length-used value in example launcher
  lguest: Segment selectors are 16-bit long. Fix lg_cpu.ss1 definition.
  lguest: beyond ARRAY_SIZE of cpu->arch.gdt
  ...
parents 16ffc3ee d1f0132e
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Documentation/lguest/Makefile
View file @ 7f3591cf
# This creates the demonstration utility "lguest" which runs a Linux guest.
CFLAGS:=-Wall -Wmissing-declarations -Wmissing-prototypes -O3 -I../../include -I../../arch/x86/include -U_FORTIFY_SOURCE
LDLIBS:=-lz
CFLAGS:=-m32 -Wall -Wmissing-declarations -Wmissing-prototypes -O3 -I../../include -I../../arch/x86/include -U_FORTIFY_SOURCE
all: lguest
......
Documentation/lguest/lguest.c
View file @ 7f3591cf
......@@ -16,6 +16,7 @@
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/eventfd.h>
#include <fcntl.h>
#include <stdbool.h>
#include <errno.h>
......@@ -59,7 +60,6 @@ typedef uint8_t u8;
/*:*/
#define PAGE_PRESENT 0x7 /* Present, RW, Execute */
#define NET_PEERNUM 1
#define BRIDGE_PFX "bridge:"
#ifndef SIOCBRADDIF
#define SIOCBRADDIF 0x89a2 /* add interface to bridge */
......@@ -76,19 +76,12 @@ static bool verbose;
do { if (verbose) printf(args); } while(0)
/*:*/
/* File descriptors for the Waker. */
struct {
int pipe[2];
int lguest_fd;
} waker_fds;
/* The pointer to the start of guest memory. */
static void *guest_base;
/* The maximum guest physical address allowed, and maximum possible. */
static unsigned long guest_limit, guest_max;
/* The pipe for signal hander to write to. */
static int timeoutpipe[2];
static unsigned int timeout_usec = 500;
/* The /dev/lguest file descriptor. */
static int lguest_fd;
/* a per-cpu variable indicating whose vcpu is currently running */
static unsigned int __thread cpu_id;
......@@ -96,11 +89,6 @@ static unsigned int __thread cpu_id;
/* This is our list of devices. */
struct device_list
{
/* Summary information about the devices in our list: ready to pass to
* select() to ask which need servicing.*/
fd_set infds;
int max_infd;
/* Counter to assign interrupt numbers. */
unsigned int next_irq;
......@@ -126,22 +114,21 @@ struct device
/* The linked-list pointer. */
struct device *next;
/* The this device's descriptor, as mapped into the Guest. */
/* The device's descriptor, as mapped into the Guest. */
struct lguest_device_desc *desc;
/* We can't trust desc values once Guest has booted: we use these. */
unsigned int feature_len;
unsigned int num_vq;
/* The name of this device, for --verbose. */
const char *name;
/* If handle_input is set, it wants to be called when this file
* descriptor is ready. */
int fd;
bool (*handle_input)(int fd, struct device *me);
/* Any queues attached to this device */
struct virtqueue *vq;
/* Handle status being finalized (ie. feature bits stable). */
void (*ready)(struct device *me);
/* Is it operational */
bool running;
/* Device-specific data. */
void *priv;
......@@ -164,22 +151,28 @@ struct virtqueue
/* Last available index we saw. */
u16 last_avail_idx;
/* The routine to call when the Guest pings us, or timeout. */
void (*handle_output)(int fd, struct virtqueue *me, bool timeout);
/* How many are used since we sent last irq? */
unsigned int pending_used;
/* Outstanding buffers */
unsigned int inflight;
/* Eventfd where Guest notifications arrive. */
int eventfd;
/* Is this blocked awaiting a timer? */
bool blocked;
/* Function for the thread which is servicing this virtqueue. */
void (*service)(struct virtqueue *vq);
pid_t thread;
};
/* Remember the arguments to the program so we can "reboot" */
static char **main_args;
/* Since guest is UP and we don't run at the same time, we don't need barriers.
* But I include them in the code in case others copy it. */
#define wmb()
/* The original tty settings to restore on exit. */
static struct termios orig_term;
/* We have to be careful with barriers: our devices are all run in separate
* threads and so we need to make sure that changes visible to the Guest happen
* in precise order. */
#define wmb() __asm__ __volatile__("" : : : "memory")
#define mb() __asm__ __volatile__("" : : : "memory")
/* Convert an iovec element to the given type.
*
......@@ -245,7 +238,7 @@ static void iov_consume(struct iovec iov[], unsigned num_iov, unsigned len)
static u8 *get_feature_bits(struct device *dev)
{
return (u8 *)(dev->desc + 1)
+ dev->desc->num_vq * sizeof(struct lguest_vqconfig);
+ dev->num_vq * sizeof(struct lguest_vqconfig);
}
/*L:100 The Launcher code itself takes us out into userspace, that scary place
......@@ -505,99 +498,19 @@ static void concat(char *dst, char *args[])
* saw the arguments it expects when we looked at initialize() in lguest_user.c:
* the base of Guest "physical" memory, the top physical page to allow and the
* entry point for the Guest. */
static int tell_kernel(unsigned long start)
static void tell_kernel(unsigned long start)
{
unsigned long args[] = { LHREQ_INITIALIZE,
(unsigned long)guest_base,
guest_limit / getpagesize(), start };
int fd;
verbose("Guest: %p - %p (%#lx)\n",
guest_base, guest_base + guest_limit, guest_limit);
fd = open_or_die("/dev/lguest", O_RDWR);
if (write(fd, args, sizeof(args)) < 0)
lguest_fd = open_or_die("/dev/lguest", O_RDWR);
if (write(lguest_fd, args, sizeof(args)) < 0)
err(1, "Writing to /dev/lguest");
/* We return the /dev/lguest file descriptor to control this Guest */
return fd;
}
/*:*/
static void add_device_fd(int fd)
{
FD_SET(fd, &devices.infds);
if (fd > devices.max_infd)
devices.max_infd = fd;
}
/*L:200
* The Waker.
*
* With console, block and network devices, we can have lots of input which we
* need to process. We could try to tell the kernel what file descriptors to
* watch, but handing a file descriptor mask through to the kernel is fairly
* icky.
*
* Instead, we clone off a thread which watches the file descriptors and writes
* the LHREQ_BREAK command to the /dev/lguest file descriptor to tell the Host
* stop running the Guest. This causes the Launcher to return from the
* /dev/lguest read with -EAGAIN, where it will write to /dev/lguest to reset
* the LHREQ_BREAK and wake us up again.
*
* This, of course, is merely a different *kind* of icky.
*
* Given my well-known antipathy to threads, I'd prefer to use processes. But
* it's easier to share Guest memory with threads, and trivial to share the
* devices.infds as the Launcher changes it.
*/
static int waker(void *unused)
{
/* Close the write end of the pipe: only the Launcher has it open. */
close(waker_fds.pipe[1]);
for (;;) {
fd_set rfds = devices.infds;
unsigned long args[] = { LHREQ_BREAK, 1 };
unsigned int maxfd = devices.max_infd;
/* We also listen to the pipe from the Launcher. */
FD_SET(waker_fds.pipe[0], &rfds);
if (waker_fds.pipe[0] > maxfd)
maxfd = waker_fds.pipe[0];
/* Wait until input is ready from one of the devices. */
select(maxfd+1, &rfds, NULL, NULL, NULL);
/* Message from Launcher? */
if (FD_ISSET(waker_fds.pipe[0], &rfds)) {
char c;
/* If this fails, then assume Launcher has exited.
* Don't do anything on exit: we're just a thread! */
if (read(waker_fds.pipe[0], &c, 1) != 1)
_exit(0);
continue;
}
/* Send LHREQ_BREAK command to snap the Launcher out of it. */
pwrite(waker_fds.lguest_fd, args, sizeof(args), cpu_id);
}
return 0;
}
/* This routine just sets up a pipe to the Waker process. */
static void setup_waker(int lguest_fd)
{
/* This pipe is closed when Launcher dies, telling Waker. */
if (pipe(waker_fds.pipe) != 0)
err(1, "Creating pipe for Waker");
/* Waker also needs to know the lguest fd */
waker_fds.lguest_fd = lguest_fd;
if (clone(waker, malloc(4096) + 4096, CLONE_VM | SIGCHLD, NULL) == -1)
err(1, "Creating Waker");
}
/*
* Device Handling.
*
......@@ -623,49 +536,90 @@ static void *_check_pointer(unsigned long addr, unsigned int size,
/* Each buffer in the virtqueues is actually a chain of descriptors. This
* function returns the next descriptor in the chain, or vq->vring.num if we're
* at the end. */
static unsigned next_desc(struct virtqueue *vq, unsigned int i)
static unsigned next_desc(struct vring_desc *desc,
unsigned int i, unsigned int max)
{
unsigned int next;
/* If this descriptor says it doesn't chain, we're done. */
if (!(vq->vring.desc[i].flags & VRING_DESC_F_NEXT))
return vq->vring.num;
if (!(desc[i].flags & VRING_DESC_F_NEXT))
return max;
/* Check they're not leading us off end of descriptors. */
next = vq->vring.desc[i].next;
next = desc[i].next;
/* Make sure compiler knows to grab that: we don't want it changing! */
wmb();
if (next >= vq->vring.num)
if (next >= max)
errx(1, "Desc next is %u", next);
return next;
}
/* This actually sends the interrupt for this virtqueue */
static void trigger_irq(struct virtqueue *vq)
{
unsigned long buf[] = { LHREQ_IRQ, vq->config.irq };
/* Don't inform them if nothing used. */
if (!vq->pending_used)
return;
vq->pending_used = 0;
/* If they don't want an interrupt, don't send one, unless empty. */
if ((vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
&& lg_last_avail(vq) != vq->vring.avail->idx)
return;
/* Send the Guest an interrupt tell them we used something up. */
if (write(lguest_fd, buf, sizeof(buf)) != 0)
err(1, "Triggering irq %i", vq->config.irq);
}
/* This looks in the virtqueue and for the first available buffer, and converts
* it to an iovec for convenient access. Since descriptors consist of some
* number of output then some number of input descriptors, it's actually two
* iovecs, but we pack them into one and note how many of each there were.
*
* This function returns the descriptor number found, or vq->vring.num (which
* is never a valid descriptor number) if none was found. */
static unsigned get_vq_desc(struct virtqueue *vq,
* This function returns the descriptor number found. */
static unsigned wait_for_vq_desc(struct virtqueue *vq,
struct iovec iov[],
unsigned int *out_num, unsigned int *in_num)
{
unsigned int i, head;
u16 last_avail;
unsigned int i, head, max;
struct vring_desc *desc;
u16 last_avail = lg_last_avail(vq);
while (last_avail == vq->vring.avail->idx) {
u64 event;
/* OK, tell Guest about progress up to now. */
trigger_irq(vq);
/* OK, now we need to know about added descriptors. */
vq->vring.used->flags &= ~VRING_USED_F_NO_NOTIFY;
/* They could have slipped one in as we were doing that: make
* sure it's written, then check again. */
mb();
if (last_avail != vq->vring.avail->idx) {
vq->vring.used->flags |= VRING_USED_F_NO_NOTIFY;
break;
}
/* Nothing new? Wait for eventfd to tell us they refilled. */
if (read(vq->eventfd, &event, sizeof(event)) != sizeof(event))
errx(1, "Event read failed?");
/* We don't need to be notified again. */
vq->vring.used->flags |= VRING_USED_F_NO_NOTIFY;
}
/* Check it isn't doing very strange things with descriptor numbers. */
last_avail = lg_last_avail(vq);
if ((u16)(vq->vring.avail->idx - last_avail) > vq->vring.num)
errx(1, "Guest moved used index from %u to %u",
last_avail, vq->vring.avail->idx);
/* If there's nothing new since last we looked, return invalid. */
if (vq->vring.avail->idx == last_avail)
return vq->vring.num;
/* Grab the next descriptor number they're advertising, and increment
* the index we've seen. */
head = vq->vring.avail->ring[last_avail % vq->vring.num];
......@@ -678,15 +632,28 @@ static unsigned get_vq_desc(struct virtqueue *vq,
/* When we start there are none of either input nor output. */
*out_num = *in_num = 0;
max = vq->vring.num;
desc = vq->vring.desc;
i = head;
/* If this is an indirect entry, then this buffer contains a descriptor
* table which we handle as if it's any normal descriptor chain. */
if (desc[i].flags & VRING_DESC_F_INDIRECT) {
if (desc[i].len % sizeof(struct vring_desc))
errx(1, "Invalid size for indirect buffer table");
max = desc[i].len / sizeof(struct vring_desc);
desc = check_pointer(desc[i].addr, desc[i].len);
i = 0;
}
do {
/* Grab the first descriptor, and check it's OK. */
iov[*out_num + *in_num].iov_len = vq->vring.desc[i].len;
iov[*out_num + *in_num].iov_len = desc[i].len;
iov[*out_num + *in_num].iov_base
= check_pointer(vq->vring.desc[i].addr,
vq->vring.desc[i].len);
= check_pointer(desc[i].addr, desc[i].len);
/* If this is an input descriptor, increment that count. */
if (vq->vring.desc[i].flags & VRING_DESC_F_WRITE)
if (desc[i].flags & VRING_DESC_F_WRITE)
(*in_num)++;
else {
/* If it's an output descriptor, they're all supposed
......@@ -697,11 +664,10 @@ static unsigned get_vq_desc(struct virtqueue *vq,
}
/* If we've got too many, that implies a descriptor loop. */
if (*out_num + *in_num > vq->vring.num)
if (*out_num + *in_num > max)
errx(1, "Looped descriptor");
} while ((i = next_desc(vq, i)) != vq->vring.num);
} while ((i = next_desc(desc, i, max)) != max);
vq->inflight++;
return head;
}
......@@ -719,44 +685,20 @@ static void add_used(struct virtqueue *vq, unsigned int head, int len)
/* Make sure buffer is written before we update index. */
wmb();
vq->vring.used->idx++;
vq->inflight--;
}
/* This actually sends the interrupt for this virtqueue */
static void trigger_irq(int fd, struct virtqueue *vq)
{
unsigned long buf[] = { LHREQ_IRQ, vq->config.irq };
/* If they don't want an interrupt, don't send one, unless empty. */
if ((vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
&& vq->inflight)
return;
/* Send the Guest an interrupt tell them we used something up. */
if (write(fd, buf, sizeof(buf)) != 0)
err(1, "Triggering irq %i", vq->config.irq);
vq->pending_used++;
}
/* And here's the combo meal deal. Supersize me! */
static void add_used_and_trigger(int fd, struct virtqueue *vq,
unsigned int head, int len)
static void add_used_and_trigger(struct virtqueue *vq, unsigned head, int len)
{
add_used(vq, head, len);
trigger_irq(fd, vq);
trigger_irq(vq);
}
/*
* The Console
*
* Here is the input terminal setting we save, and the routine to restore them
* on exit so the user gets their terminal back. */
static struct termios orig_term;
static void restore_term(void)
{
tcsetattr(STDIN_FILENO, TCSANOW, &orig_term);
}
/* We associate some data with the console for our exit hack. */
* We associate some data with the console for our exit hack. */
struct console_abort
{
/* How many times have they hit ^C? */
......@@ -766,276 +708,275 @@ struct console_abort
};
/* This is the routine which handles console input (ie. stdin). */
static bool handle_console_input(int fd, struct device *dev)
static void console_input(struct virtqueue *vq)
{
int len;
unsigned int head, in_num, out_num;
struct iovec iov[dev->vq->vring.num];
struct console_abort *abort = dev->priv;
/* First we need a console buffer from the Guests's input virtqueue. */
head = get_vq_desc(dev->vq, iov, &out_num, &in_num);
/* If they're not ready for input, stop listening to this file
* descriptor. We'll start again once they add an input buffer. */
if (head == dev->vq->vring.num)
return false;
struct console_abort *abort = vq->dev->priv;
struct iovec iov[vq->vring.num];
/* Make sure there's a descriptor waiting. */
head = wait_for_vq_desc(vq, iov, &out_num, &in_num);
if (out_num)
errx(1, "Output buffers in console in queue?");
/* This is why we convert to iovecs: the readv() call uses them, and so
* it reads straight into the Guest's buffer. */
len = readv(dev->fd, iov, in_num);
/* Read it in. */
len = readv(STDIN_FILENO, iov, in_num);
if (len <= 0) {
/* This implies that the console is closed, is /dev/null, or
* something went terribly wrong. */
/* Ran out of input? */
warnx("Failed to get console input, ignoring console.");
/* Put the input terminal back. */
restore_term();
/* Remove callback from input vq, so it doesn't restart us. */
dev->vq->handle_output = NULL;
/* Stop listening to this fd: don't call us again. */
return false;
/* For simplicity, dying threads kill the whole Launcher. So
* just nap here. */
for (;;)
pause();
}
/* Tell the Guest about the new input. */
add_used_and_trigger(fd, dev->vq, head, len);
add_used_and_trigger(vq, head, len);
/* Three ^C within one second? Exit.
*
* This is such a hack, but works surprisingly well. Each ^C has to be
* in a buffer by itself, so they can't be too fast. But we check that
* we get three within about a second, so they can't be too slow. */
if (len == 1 && ((char *)iov[0].iov_base)[0] == 3) {
if (!abort->count++)
* This is such a hack, but works surprisingly well. Each ^C has to
* be in a buffer by itself, so they can't be too fast. But we check
* that we get three within about a second, so they can't be too
* slow. */
if (len != 1 || ((char *)iov[0].iov_base)[0] != 3) {
abort->count = 0;
return;
}
abort->count++;
if (abort->count == 1)
gettimeofday(&abort->start, NULL);
else if (abort->count == 3) {
struct timeval now;
gettimeofday(&now, NULL);
if (now.tv_sec <= abort->start.tv_sec+1) {
unsigned long args[] = { LHREQ_BREAK, 0 };
/* Close the fd so Waker will know it has to
* exit. */
close(waker_fds.pipe[1]);
/* Just in case Waker is blocked in BREAK, send
* unbreak now. */
write(fd, args, sizeof(args));
exit(2);
}
/* Kill all Launcher processes with SIGINT, like normal ^C */
if (now.tv_sec <= abort->start.tv_sec+1)
kill(0, SIGINT);
abort->count = 0;
}
} else
/* Any other key resets the abort counter. */
abort->count = 0;
/* Everything went OK! */
return true;
}
/* Handling output for console is simple: we just get all the output buffers
* and write them to stdout. */
static void handle_console_output(int fd, struct virtqueue *vq, bool timeout)
/* This is the routine which handles console output (ie. stdout). */
static void console_output(struct virtqueue *vq)
{
unsigned int head, out, in;
int len;
struct iovec iov[vq->vring.num];
/* Keep getting output buffers from the Guest until we run out. */
while ((head = get_vq_desc(vq, iov, &out, &in)) != vq->vring.num) {
head = wait_for_vq_desc(vq, iov, &out, &in);
if (in)
errx(1, "Input buffers in output queue?");
len = writev(STDOUT_FILENO, iov, out);
add_used_and_trigger(fd, vq, head, len);
errx(1, "Input buffers in console output queue?");
while (!iov_empty(iov, out)) {
int len = writev(STDOUT_FILENO, iov, out);
if (len <= 0)
err(1, "Write to stdout gave %i", len);
iov_consume(iov, out, len);
}
}
/* This is called when we no longer want to hear about Guest changes to a
* virtqueue. This is more efficient in high-traffic cases, but it means we
* have to set a timer to check if any more changes have occurred. */
static void block_vq(struct virtqueue *vq)
{
struct itimerval itm;
vq->vring.used->flags |= VRING_USED_F_NO_NOTIFY;
vq->blocked = true;
itm.it_interval.tv_sec = 0;
itm.it_interval.tv_usec = 0;
itm.it_value.tv_sec = 0;
itm.it_value.tv_usec = timeout_usec;
setitimer(ITIMER_REAL, &itm, NULL);
add_used(vq, head, 0);
}
/*
* The Network
*
* Handling output for network is also simple: we get all the output buffers
* and write them (ignoring the first element) to this device's file descriptor
* (/dev/net/tun).
* and write them to /dev/net/tun.
*/
static void handle_net_output(int fd, struct virtqueue *vq, bool timeout)
struct net_info {
int tunfd;
};
static void net_output(struct virtqueue *vq)
{
unsigned int head, out, in, num = 0;
int len;
struct net_info *net_info = vq->dev->priv;
unsigned int head, out, in;
struct iovec iov[vq->vring.num];
static int last_timeout_num;
/* Keep getting output buffers from the Guest until we run out. */
while ((head = get_vq_desc(vq, iov, &out, &in)) != vq->vring.num) {
head = wait_for_vq_desc(vq, iov, &out, &in);
if (in)
errx(1, "Input buffers in output queue?");
len = writev(vq->dev->fd, iov, out);
if (len < 0)
err(1, "Writing network packet to tun");
add_used_and_trigger(fd, vq, head, len);
num++;
}
errx(1, "Input buffers in net output queue?");
if (writev(net_info->tunfd, iov, out) < 0)
errx(1, "Write to tun failed?");
add_used(vq, head, 0);
}
/* Block further kicks and set up a timer if we saw anything. */
if (!timeout && num)
block_vq(vq);
/* We never quite know how long should we wait before we check the
* queue again for more packets. We start at 500 microseconds, and if
* we get fewer packets than last time, we assume we made the timeout
* too small and increase it by 10 microseconds. Otherwise, we drop it
* by one microsecond every time. It seems to work well enough. */
if (timeout) {
if (num < last_timeout_num)
timeout_usec += 10;
else if (timeout_usec > 1)
timeout_usec--;
last_timeout_num = num;
}
/* Will reading from this file descriptor block? */
static bool will_block(int fd)
{
fd_set fdset;
struct timeval zero = { 0, 0 };
FD_ZERO(&fdset);
FD_SET(fd, &fdset);
return select(fd+1, &fdset, NULL, NULL, &zero) != 1;
}
/* This is where we handle a packet coming in from the tun device to our
/* This is where we handle packets coming in from the tun device to our
* Guest. */
static bool handle_tun_input(int fd, struct device *dev)
static void net_input(struct virtqueue *vq)
{
unsigned int head, in_num, out_num;
int len;
struct iovec iov[dev->vq->vring.num];
/* First we need a network buffer from the Guests's recv virtqueue. */
head = get_vq_desc(dev->vq, iov, &out_num, &in_num);
if (head == dev->vq->vring.num) {
/* Now, it's expected that if we try to send a packet too
* early, the Guest won't be ready yet. Wait until the device
* status says it's ready. */
/* FIXME: Actually want DRIVER_ACTIVE here. */
/* Now tell it we want to know if new things appear. */
dev->vq->vring.used->flags &= ~VRING_USED_F_NO_NOTIFY;
wmb();
/* We'll turn this back on if input buffers are registered. */
return false;
} else if (out_num)
errx(1, "Output buffers in network recv queue?");
/* Read the packet from the device directly into the Guest's buffer. */
len = readv(dev->fd, iov, in_num);
if (len <= 0)
err(1, "reading network");
unsigned int head, out, in;
struct iovec iov[vq->vring.num];
struct net_info *net_info = vq->dev->priv;
/* Tell the Guest about the new packet. */
add_used_and_trigger(fd, dev->vq, head, len);
head = wait_for_vq_desc(vq, iov, &out, &in);
if (out)
errx(1, "Output buffers in net input queue?");
verbose("tun input packet len %i [%02x %02x] (%s)\n", len,
((u8 *)iov[1].iov_base)[0], ((u8 *)iov[1].iov_base)[1],
head != dev->vq->vring.num ? "sent" : "discarded");
/* Deliver interrupt now, since we're about to sleep. */
if (vq->pending_used && will_block(net_info->tunfd))
trigger_irq(vq);
/* All good. */
return true;
len = readv(net_info->tunfd, iov, in);
if (len <= 0)
err(1, "Failed to read from tun.");
add_used(vq, head, len);
}
/*L:215 This is the callback attached to the network and console input
* virtqueues: it ensures we try again, in case we stopped console or net
* delivery because Guest didn't have any buffers. */
static void enable_fd(int fd, struct virtqueue *vq, bool timeout)
/* This is the helper to create threads. */
static int do_thread(void *_vq)
{
add_device_fd(vq->dev->fd);
/* Snap the Waker out of its select loop. */
write(waker_fds.pipe[1], "", 1);
struct virtqueue *vq = _vq;
for (;;)
vq->service(vq);
return 0;
}
static void net_enable_fd(int fd, struct virtqueue *vq, bool timeout)
/* When a child dies, we kill our entire process group with SIGTERM. This
* also has the side effect that the shell restores the console for us! */
static void kill_launcher(int signal)
{
/* We don't need to know again when Guest refills receive buffer. */
vq->vring.used->flags |= VRING_USED_F_NO_NOTIFY;
enable_fd(fd, vq, timeout);
kill(0, SIGTERM);
}
/* When the Guest tells us they updated the status field, we handle it. */
static void update_device_status(struct device *dev)
static void reset_device(struct device *dev)
{
struct virtqueue *vq;
/* This is a reset. */
if (dev->desc->status == 0) {
verbose("Resetting device %s\n", dev->name);
/* Clear any features they've acked. */
memset(get_feature_bits(dev) + dev->desc->feature_len, 0,
dev->desc->feature_len);
memset(get_feature_bits(dev) + dev->feature_len, 0, dev->feature_len);
/* Zero out the virtqueues. */
/* We're going to be explicitly killing threads, so ignore them. */
signal(SIGCHLD, SIG_IGN);
/* Zero out the virtqueues, get rid of their threads */
for (vq = dev->vq; vq; vq = vq->next) {
if (vq->thread != (pid_t)-1) {
kill(vq->thread, SIGTERM);
waitpid(vq->thread, NULL, 0);
vq->thread = (pid_t)-1;
}
memset(vq->vring.desc, 0,
vring_size(vq->config.num, LGUEST_VRING_ALIGN));
lg_last_avail(vq) = 0;
}
} else if (dev->desc->status & VIRTIO_CONFIG_S_FAILED) {
warnx("Device %s configuration FAILED", dev->name);
} else if (dev->desc->status & VIRTIO_CONFIG_S_DRIVER_OK) {
dev->running = false;
/* Now we care if threads die. */
signal(SIGCHLD, (void *)kill_launcher);
}
static void create_thread(struct virtqueue *vq)
{
/* Create stack for thread and run it. Since stack grows
* upwards, we point the stack pointer to the end of this
* region. */
char *stack = malloc(32768);
unsigned long args[] = { LHREQ_EVENTFD,
vq->config.pfn*getpagesize(), 0 };
/* Create a zero-initialized eventfd. */
vq->eventfd = eventfd(0, 0);
if (vq->eventfd < 0)
err(1, "Creating eventfd");
args[2] = vq->eventfd;
/* Attach an eventfd to this virtqueue: it will go off
* when the Guest does an LHCALL_NOTIFY for this vq. */
if (write(lguest_fd, &args, sizeof(args)) != 0)
err(1, "Attaching eventfd");
/* CLONE_VM: because it has to access the Guest memory, and
* SIGCHLD so we get a signal if it dies. */
vq->thread = clone(do_thread, stack + 32768, CLONE_VM | SIGCHLD, vq);
if (vq->thread == (pid_t)-1)
err(1, "Creating clone");
/* We close our local copy, now the child has it. */
close(vq->eventfd);
}
static void start_device(struct device *dev)
{
unsigned int i;
struct virtqueue *vq;
verbose("Device %s OK: offered", dev->name);
for (i = 0; i < dev->desc->feature_len; i++)
for (i = 0; i < dev->feature_len; i++)
verbose(" %02x", get_feature_bits(dev)[i]);
verbose(", accepted");
for (i = 0; i < dev->desc->feature_len; i++)
for (i = 0; i < dev->feature_len; i++)
verbose(" %02x", get_feature_bits(dev)
[dev->desc->feature_len+i]);
[dev->feature_len+i]);
if (dev->ready)
dev->ready(dev);
for (vq = dev->vq; vq; vq = vq->next) {
if (vq->service)
create_thread(vq);
}
dev->running = true;
}
static void cleanup_devices(void)
{
struct device *dev;
for (dev = devices.dev; dev; dev = dev->next)
reset_device(dev);
/* If we saved off the original terminal settings, restore them now. */
if (orig_term.c_lflag & (ISIG|ICANON|ECHO))
tcsetattr(STDIN_FILENO, TCSANOW, &orig_term);
}
/* When the Guest tells us they updated the status field, we handle it. */
static void update_device_status(struct device *dev)
{
/* A zero status is a reset, otherwise it's a set of flags. */
if (dev->desc->status == 0)
reset_device(dev);
else if (dev->desc->status & VIRTIO_CONFIG_S_FAILED) {
warnx("Device %s configuration FAILED", dev->name);
if (dev->running)
reset_device(dev);
} else if (dev->desc->status & VIRTIO_CONFIG_S_DRIVER_OK) {
if (!dev->running)
start_device(dev);
}
}
/* This is the generic routine we call when the Guest uses LHCALL_NOTIFY. */
static void handle_output(int fd, unsigned long addr)
static void handle_output(unsigned long addr)
{
struct device *i;
struct virtqueue *vq;
/* Check each device and virtqueue. */
/* Check each device. */
for (i = devices.dev; i; i = i->next) {
struct virtqueue *vq;
/* Notifications to device descriptors update device status. */
if (from_guest_phys(addr) == i->desc) {
update_device_status(i);
return;
}
/* Notifications to virtqueues mean output has occurred. */
/* Devices *can* be used before status is set to DRIVER_OK. */
for (vq = i->vq; vq; vq = vq->next) {
if (vq->config.pfn != addr/getpagesize())
if (addr != vq->config.pfn*getpagesize())
continue;
/* Guest should acknowledge (and set features!) before
* using the device. */
if (i->desc->status == 0) {
warnx("%s gave early output", i->name);
return;
}
if (strcmp(vq->dev->name, "console") != 0)
verbose("Output to %s\n", vq->dev->name);
if (vq->handle_output)
vq->handle_output(fd, vq, false);
if (i->running)
errx(1, "Notification on running %s", i->name);
start_device(i);
return;
}
}
......@@ -1049,71 +990,6 @@ static void handle_output(int fd, unsigned long addr)
strnlen(from_guest_phys(addr), guest_limit - addr));
}
static void handle_timeout(int fd)
{
char buf[32];
struct device *i;
struct virtqueue *vq;
/* Clear the pipe */
read(timeoutpipe[0], buf, sizeof(buf));
/* Check each device and virtqueue: flush blocked ones. */
for (i = devices.dev; i; i = i->next) {
for (vq = i->vq; vq; vq = vq->next) {
if (!vq->blocked)
continue;
vq->vring.used->flags &= ~VRING_USED_F_NO_NOTIFY;
vq->blocked = false;
if (vq->handle_output)
vq->handle_output(fd, vq, true);
}
}
}
/* This is called when the Waker wakes us up: check for incoming file
* descriptors. */
static void handle_input(int fd)
{
/* select() wants a zeroed timeval to mean "don't wait". */
struct timeval poll = { .tv_sec = 0, .tv_usec = 0 };
for (;;) {
struct device *i;
fd_set fds = devices.infds;
int num;
num = select(devices.max_infd+1, &fds, NULL, NULL, &poll);
/* Could get interrupted */
if (num < 0)
continue;
/* If nothing is ready, we're done. */
if (num == 0)
break;
/* Otherwise, call the device(s) which have readable file
* descriptors and a method of handling them. */
for (i = devices.dev; i; i = i->next) {
if (i->handle_input && FD_ISSET(i->fd, &fds)) {
if (i->handle_input(fd, i))
continue;
/* If handle_input() returns false, it means we
* should no longer service it. Networking and
* console do this when there's no input
* buffers to deliver into. Console also uses
* it when it discovers that stdin is closed. */
FD_CLR(i->fd, &devices.infds);
}
}
/* Is this the timeout fd? */
if (FD_ISSET(timeoutpipe[0], &fds))
handle_timeout(fd);
}
}
/*L:190
* Device Setup
*
......@@ -1129,8 +1005,8 @@ static void handle_input(int fd)
static u8 *device_config(const struct device *dev)
{
return (void *)(dev->desc + 1)
+ dev->desc->num_vq * sizeof(struct lguest_vqconfig)
+ dev->desc->feature_len * 2;
+ dev->num_vq * sizeof(struct lguest_vqconfig)
+ dev->feature_len * 2;
}
/* This routine allocates a new "struct lguest_device_desc" from descriptor
......@@ -1159,7 +1035,7 @@ static struct lguest_device_desc *new_dev_desc(u16 type)
/* Each device descriptor is followed by the description of its virtqueues. We
* specify how many descriptors the virtqueue is to have. */
static void add_virtqueue(struct device *dev, unsigned int num_descs,
void (*handle_output)(int, struct virtqueue *, bool))
void (*service)(struct virtqueue *))
{
unsigned int pages;
struct virtqueue **i, *vq = malloc(sizeof(*vq));
......@@ -1174,8 +1050,8 @@ static void add_virtqueue(struct device *dev, unsigned int num_descs,
vq->next = NULL;
vq->last_avail_idx = 0;
vq->dev = dev;
vq->inflight = 0;
vq->blocked = false;
vq->service = service;
vq->thread = (pid_t)-1;
/* Initialize the configuration. */
vq->config.num = num_descs;
......@@ -1191,6 +1067,7 @@ static void add_virtqueue(struct device *dev, unsigned int num_descs,
* yet, otherwise we'd be overwriting them. */
assert(dev->desc->config_len == 0 && dev->desc->feature_len == 0);
memcpy(device_config(dev), &vq->config, sizeof(vq->config));
dev->num_vq++;
dev->desc->num_vq++;
verbose("Virtqueue page %#lx\n", to_guest_phys(p));
......@@ -1199,15 +1076,6 @@ static void add_virtqueue(struct device *dev, unsigned int num_descs,
* second. */
for (i = &dev->vq; *i; i = &(*i)->next);
*i = vq;
/* Set the routine to call when the Guest does something to this
* virtqueue. */
vq->handle_output = handle_output;
/* As an optimization, set the advisory "Don't Notify Me" flag if we
* don't have a handler */
if (!handle_output)
vq->vring.used->flags = VRING_USED_F_NO_NOTIFY;
}
/* The first half of the feature bitmask is for us to advertise features. The
......@@ -1219,7 +1087,7 @@ static void add_feature(struct device *dev, unsigned bit)
/* We can't extend the feature bits once we've added config bytes */
if (dev->desc->feature_len <= bit / CHAR_BIT) {
assert(dev->desc->config_len == 0);
dev->desc->feature_len = (bit / CHAR_BIT) + 1;
dev->feature_len = dev->desc->feature_len = (bit/CHAR_BIT) + 1;
}
features[bit / CHAR_BIT] |= (1 << (bit % CHAR_BIT));
......@@ -1243,22 +1111,17 @@ static void set_config(struct device *dev, unsigned len, const void *conf)
* calling new_dev_desc() to allocate the descriptor and device memory.
*
* See what I mean about userspace being boring? */
static struct device *new_device(const char *name, u16 type, int fd,
bool (*handle_input)(int, struct device *))
static struct device *new_device(const char *name, u16 type)
{
struct device *dev = malloc(sizeof(*dev));
/* Now we populate the fields one at a time. */
dev->fd = fd;
/* If we have an input handler for this file descriptor, then we add it
* to the device_list's fdset and maxfd. */
if (handle_input)
add_device_fd(dev->fd);
dev->desc = new_dev_desc(type);
dev->handle_input = handle_input;
dev->name = name;
dev->vq = NULL;
dev->ready = NULL;
dev->feature_len = 0;
dev->num_vq = 0;
dev->running = false;
/* Append to device list. Prepending to a single-linked list is
* easier, but the user expects the devices to be arranged on the bus
......@@ -1286,13 +1149,10 @@ static void setup_console(void)
* raw input stream to the Guest. */
term.c_lflag &= ~(ISIG|ICANON|ECHO);
tcsetattr(STDIN_FILENO, TCSANOW, &term);
/* If we exit gracefully, the original settings will be
* restored so the user can see what they're typing. */
atexit(restore_term);
}
dev = new_device("console", VIRTIO_ID_CONSOLE,
STDIN_FILENO, handle_console_input);
dev = new_device("console", VIRTIO_ID_CONSOLE);
/* We store the console state in dev->priv, and initialize it. */
dev->priv = malloc(sizeof(struct console_abort));
((struct console_abort *)dev->priv)->count = 0;
......@@ -1301,31 +1161,13 @@ static void setup_console(void)
* they put something the input queue, we make sure we're listening to
* stdin. When they put something in the output queue, we write it to
* stdout. */
add_virtqueue(dev, VIRTQUEUE_NUM, enable_fd);
add_virtqueue(dev, VIRTQUEUE_NUM, handle_console_output);
add_virtqueue(dev, VIRTQUEUE_NUM, console_input);
add_virtqueue(dev, VIRTQUEUE_NUM, console_output);
verbose("device %u: console\n", devices.device_num++);
verbose("device %u: console\n", ++devices.device_num);
}
/*:*/
static void timeout_alarm(int sig)
{
write(timeoutpipe[1], "", 1);
}
static void setup_timeout(void)
{
if (pipe(timeoutpipe) != 0)
err(1, "Creating timeout pipe");
if (fcntl(timeoutpipe[1], F_SETFL,
fcntl(timeoutpipe[1], F_GETFL) | O_NONBLOCK) != 0)
err(1, "Making timeout pipe nonblocking");
add_device_fd(timeoutpipe[0]);
signal(SIGALRM, timeout_alarm);
}
/*M:010 Inter-guest networking is an interesting area. Simplest is to have a
* --sharenet=<name> option which opens or creates a named pipe. This can be
* used to send packets to another guest in a 1:1 manner.
......@@ -1447,21 +1289,23 @@ static int get_tun_device(char tapif[IFNAMSIZ])
static void setup_tun_net(char *arg)
{
struct device *dev;
int netfd, ipfd;
struct net_info *net_info = malloc(sizeof(*net_info));
int ipfd;
u32 ip = INADDR_ANY;
bool bridging = false;
char tapif[IFNAMSIZ], *p;
struct virtio_net_config conf;
netfd = get_tun_device(tapif);
net_info->tunfd = get_tun_device(tapif);
/* First we create a new network device. */
dev = new_device("net", VIRTIO_ID_NET, netfd, handle_tun_input);
dev = new_device("net", VIRTIO_ID_NET);
dev->priv = net_info;
/* Network devices need a receive and a send queue, just like
* console. */
add_virtqueue(dev, VIRTQUEUE_NUM, net_enable_fd);
add_virtqueue(dev, VIRTQUEUE_NUM, handle_net_output);
add_virtqueue(dev, VIRTQUEUE_NUM, net_input);
add_virtqueue(dev, VIRTQUEUE_NUM, net_output);
/* We need a socket to perform the magic network ioctls to bring up the
* tap interface, connect to the bridge etc. Any socket will do! */
......@@ -1502,6 +1346,8 @@ static void setup_tun_net(char *arg)
add_feature(dev, VIRTIO_NET_F_HOST_TSO4);
add_feature(dev, VIRTIO_NET_F_HOST_TSO6);
add_feature(dev, VIRTIO_NET_F_HOST_ECN);
/* We handle indirect ring entries */
add_feature(dev, VIRTIO_RING_F_INDIRECT_DESC);
set_config(dev, sizeof(conf), &conf);
/* We don't need the socket any more; setup is done. */
......@@ -1550,20 +1396,18 @@ struct vblk_info
* Remember that the block device is handled by a separate I/O thread. We head
* straight into the core of that thread here:
*/
static bool service_io(struct device *dev)
static void blk_request(struct virtqueue *vq)
{
struct vblk_info *vblk = dev->priv;
struct vblk_info *vblk = vq->dev->priv;
unsigned int head, out_num, in_num, wlen;
int ret;
u8 *in;
struct virtio_blk_outhdr *out;
struct iovec iov[dev->vq->vring.num];
struct iovec iov[vq->vring.num];
off64_t off;
/* See if there's a request waiting. If not, nothing to do. */
head = get_vq_desc(dev->vq, iov, &out_num, &in_num);
if (head == dev->vq->vring.num)
return false;
/* Get the next request. */
head = wait_for_vq_desc(vq, iov, &out_num, &in_num);
/* Every block request should contain at least one output buffer
* (detailing the location on disk and the type of request) and one
......@@ -1637,83 +1481,21 @@ static bool service_io(struct device *dev)
if (out->type & VIRTIO_BLK_T_BARRIER)
fdatasync(vblk->fd);
/* We can't trigger an IRQ, because we're not the Launcher. It does
* that when we tell it we're done. */
add_used(dev->vq, head, wlen);
return true;
}
/* This is the thread which actually services the I/O. */
static int io_thread(void *_dev)
{
struct device *dev = _dev;
struct vblk_info *vblk = dev->priv;
char c;
/* Close other side of workpipe so we get 0 read when main dies. */
close(vblk->workpipe[1]);
/* Close the other side of the done_fd pipe. */
close(dev->fd);
/* When this read fails, it means Launcher died, so we follow. */
while (read(vblk->workpipe[0], &c, 1) == 1) {
/* We acknowledge each request immediately to reduce latency,
* rather than waiting until we've done them all. I haven't
* measured to see if it makes any difference.
*
* That would be an interesting test, wouldn't it? You could
* also try having more than one I/O thread. */
while (service_io(dev))
write(vblk->done_fd, &c, 1);
}
return 0;
}
/* Now we've seen the I/O thread, we return to the Launcher to see what happens
* when that thread tells us it's completed some I/O. */
static bool handle_io_finish(int fd, struct device *dev)
{
char c;
/* If the I/O thread died, presumably it printed the error, so we
* simply exit. */
if (read(dev->fd, &c, 1) != 1)
exit(1);
/* It did some work, so trigger the irq. */
trigger_irq(fd, dev->vq);
return true;
}
/* When the Guest submits some I/O, we just need to wake the I/O thread. */
static void handle_virtblk_output(int fd, struct virtqueue *vq, bool timeout)
{
struct vblk_info *vblk = vq->dev->priv;
char c = 0;
/* Wake up I/O thread and tell it to go to work! */
if (write(vblk->workpipe[1], &c, 1) != 1)
/* Presumably it indicated why it died. */
exit(1);
add_used(vq, head, wlen);
}
/*L:198 This actually sets up a virtual block device. */
static void setup_block_file(const char *filename)
{
int p[2];
struct device *dev;
struct vblk_info *vblk;
void *stack;
struct virtio_blk_config conf;
/* This is the pipe the I/O thread will use to tell us I/O is done. */
pipe(p);
/* The device responds to return from I/O thread. */
dev = new_device("block", VIRTIO_ID_BLOCK, p[0], handle_io_finish);
dev = new_device("block", VIRTIO_ID_BLOCK);
/* The device has one virtqueue, where the Guest places requests. */
add_virtqueue(dev, VIRTQUEUE_NUM, handle_virtblk_output);
add_virtqueue(dev, VIRTQUEUE_NUM, blk_request);
/* Allocate the room for our own bookkeeping */
vblk = dev->priv = malloc(sizeof(*vblk));
......@@ -1735,49 +1517,29 @@ static void setup_block_file(const char *filename)
set_config(dev, sizeof(conf), &conf);
/* The I/O thread writes to this end of the pipe when done. */
vblk->done_fd = p[1];
/* This is the second pipe, which is how we tell the I/O thread about
* more work. */
pipe(vblk->workpipe);
/* Create stack for thread and run it. Since stack grows upwards, we
* point the stack pointer to the end of this region. */
stack = malloc(32768);
/* SIGCHLD - We dont "wait" for our cloned thread, so prevent it from
* becoming a zombie. */
if (clone(io_thread, stack + 32768, CLONE_VM | SIGCHLD, dev) == -1)
err(1, "Creating clone");
/* We don't need to keep the I/O thread's end of the pipes open. */
close(vblk->done_fd);
close(vblk->workpipe[0]);
verbose("device %u: virtblock %llu sectors\n",
devices.device_num, le64_to_cpu(conf.capacity));
++devices.device_num, le64_to_cpu(conf.capacity));
}
struct rng_info {
int rfd;
};
/* Our random number generator device reads from /dev/random into the Guest's
* input buffers. The usual case is that the Guest doesn't want random numbers
* and so has no buffers although /dev/random is still readable, whereas
* console is the reverse.
*
* The same logic applies, however. */
static bool handle_rng_input(int fd, struct device *dev)
static void rng_input(struct virtqueue *vq)
{
int len;
unsigned int head, in_num, out_num, totlen = 0;
struct iovec iov[dev->vq->vring.num];
struct rng_info *rng_info = vq->dev->priv;
struct iovec iov[vq->vring.num];
/* First we need a buffer from the Guests's virtqueue. */
head = get_vq_desc(dev->vq, iov, &out_num, &in_num);
/* If they're not ready for input, stop listening to this file
* descriptor. We'll start again once they add an input buffer. */
if (head == dev->vq->vring.num)
return false;
head = wait_for_vq_desc(vq, iov, &out_num, &in_num);
if (out_num)
errx(1, "Output buffers in rng?");
......@@ -1785,7 +1547,7 @@ static bool handle_rng_input(int fd, struct device *dev)
* it reads straight into the Guest's buffer. We loop to make sure we
* fill it. */
while (!iov_empty(iov, in_num)) {
len = readv(dev->fd, iov, in_num);
len = readv(rng_info->rfd, iov, in_num);
if (len <= 0)
err(1, "Read from /dev/random gave %i", len);
iov_consume(iov, in_num, len);
......@@ -1793,25 +1555,23 @@ static bool handle_rng_input(int fd, struct device *dev)
}
/* Tell the Guest about the new input. */
add_used_and_trigger(fd, dev->vq, head, totlen);
/* Everything went OK! */
return true;
add_used(vq, head, totlen);
}
/* And this creates a "hardware" random number device for the Guest. */
static void setup_rng(void)
{
struct device *dev;
int fd;
struct rng_info *rng_info = malloc(sizeof(*rng_info));
fd = open_or_die("/dev/random", O_RDONLY);
rng_info->rfd = open_or_die("/dev/random", O_RDONLY);
/* The device responds to return from I/O thread. */
dev = new_device("rng", VIRTIO_ID_RNG, fd, handle_rng_input);
dev = new_device("rng", VIRTIO_ID_RNG);
dev->priv = rng_info;
/* The device has one virtqueue, where the Guest places inbufs. */
add_virtqueue(dev, VIRTQUEUE_NUM, enable_fd);
add_virtqueue(dev, VIRTQUEUE_NUM, rng_input);
verbose("device %u: rng\n", devices.device_num++);
}
......@@ -1827,17 +1587,18 @@ static void __attribute__((noreturn)) restart_guest(void)
for (i = 3; i < FD_SETSIZE; i++)
close(i);
/* The exec automatically gets rid of the I/O and Waker threads. */
/* Reset all the devices (kills all threads). */
cleanup_devices();
execv(main_args[0], main_args);
err(1, "Could not exec %s", main_args[0]);
}
/*L:220 Finally we reach the core of the Launcher which runs the Guest, serves
* its input and output, and finally, lays it to rest. */
static void __attribute__((noreturn)) run_guest(int lguest_fd)
static void __attribute__((noreturn)) run_guest(void)
{
for (;;) {
unsigned long args[] = { LHREQ_BREAK, 0 };
unsigned long notify_addr;
int readval;
......@@ -1848,8 +1609,7 @@ static void __attribute__((noreturn)) run_guest(int lguest_fd)
/* One unsigned long means the Guest did HCALL_NOTIFY */
if (readval == sizeof(notify_addr)) {
verbose("Notify on address %#lx\n", notify_addr);
handle_output(lguest_fd, notify_addr);
continue;
handle_output(notify_addr);
/* ENOENT means the Guest died. Reading tells us why. */
} else if (errno == ENOENT) {
char reason[1024] = { 0 };
......@@ -1858,19 +1618,9 @@ static void __attribute__((noreturn)) run_guest(int lguest_fd)
/* ERESTART means that we need to reboot the guest */
} else if (errno == ERESTART) {
restart_guest();
/* EAGAIN means a signal (timeout).
* Anything else means a bug or incompatible change. */
} else if (errno != EAGAIN)
/* Anything else means a bug or incompatible change. */
} else
err(1, "Running guest failed");
/* Only service input on thread for CPU 0. */
if (cpu_id != 0)
continue;
/* Service input, then unset the BREAK to release the Waker. */
handle_input(lguest_fd);
if (pwrite(lguest_fd, args, sizeof(args), cpu_id) < 0)
err(1, "Resetting break");
}
}
/*L:240
......@@ -1904,8 +1654,8 @@ int main(int argc, char *argv[])
/* Memory, top-level pagetable, code startpoint and size of the
* (optional) initrd. */
unsigned long mem = 0, start, initrd_size = 0;
/* Two temporaries and the /dev/lguest file descriptor. */
int i, c, lguest_fd;
/* Two temporaries. */
int i, c;
/* The boot information for the Guest. */
struct boot_params *boot;
/* If they specify an initrd file to load. */
......@@ -1913,18 +1663,10 @@ int main(int argc, char *argv[])
/* Save the args: we "reboot" by execing ourselves again. */
main_args = argv;
/* We don't "wait" for the children, so prevent them from becoming
* zombies. */
signal(SIGCHLD, SIG_IGN);
/* First we initialize the device list. Since console and network
* device receive input from a file descriptor, we keep an fdset
* (infds) and the maximum fd number (max_infd) with the head of the
* list. We also keep a pointer to the last device. Finally, we keep
* the next interrupt number to use for devices (1: remember that 0 is
* used by the timer). */
FD_ZERO(&devices.infds);
devices.max_infd = -1;
/* First we initialize the device list. We keep a pointer to the last
* device, and the next interrupt number to use for devices (1:
* remember that 0 is used by the timer). */
devices.lastdev = NULL;
devices.next_irq = 1;
......@@ -1982,9 +1724,6 @@ int main(int argc, char *argv[])
/* We always have a console device */
setup_console();
/* We can timeout waiting for Guest network transmit. */
setup_timeout();
/* Now we load the kernel */
start = load_kernel(open_or_die(argv[optind+1], O_RDONLY));
......@@ -2023,15 +1762,16 @@ int main(int argc, char *argv[])
/* We tell the kernel to initialize the Guest: this returns the open
* /dev/lguest file descriptor. */
lguest_fd = tell_kernel(start);
tell_kernel(start);
/* Ensure that we terminate if a child dies. */
signal(SIGCHLD, kill_launcher);
/* We clone off a thread, which wakes the Launcher whenever one of the
* input file descriptors needs attention. We call this the Waker, and
* we'll cover it in a moment. */
setup_waker(lguest_fd);
/* If we exit via err(), this kills all the threads, restores tty. */
atexit(cleanup_devices);
/* Finally, run the Guest. This doesn't return. */
run_guest(lguest_fd);
run_guest();
}
/*:*/
......
Documentation/lguest/lguest.txt
View file @ 7f3591cf
......@@ -37,7 +37,6 @@ Running Lguest:
"Paravirtualized guest support" = Y
"Lguest guest support" = Y
"High Memory Support" = off/4GB
"PAE (Physical Address Extension) Support" = N
"Alignment value to which kernel should be aligned" = 0x100000
(CONFIG_PARAVIRT=y, CONFIG_LGUEST_GUEST=y, CONFIG_HIGHMEM64G=n and
CONFIG_PHYSICAL_ALIGN=0x100000)
......
arch/x86/include/asm/lguest.h
View file @ 7f3591cf
......@@ -17,8 +17,13 @@
/* Pages for switcher itself, then two pages per cpu */
#define TOTAL_SWITCHER_PAGES (SHARED_SWITCHER_PAGES + 2 * nr_cpu_ids)
/* We map at -4M for ease of mapping into the guest (one PTE page). */
/* We map at -4M (-2M when PAE is activated) for ease of mapping
* into the guest (one PTE page). */
#ifdef CONFIG_X86_PAE
#define SWITCHER_ADDR 0xFFE00000
#else
#define SWITCHER_ADDR 0xFFC00000
#endif
/* Found in switcher.S */
extern unsigned long default_idt_entries[];
......
arch/x86/include/asm/lguest_hcall.h
View file @ 7f3591cf
......@@ -12,11 +12,13 @@
#define LHCALL_TS 8
#define LHCALL_SET_CLOCKEVENT 9
#define LHCALL_HALT 10
#define LHCALL_SET_PMD 13
#define LHCALL_SET_PTE 14
#define LHCALL_SET_PMD 15
#define LHCALL_SET_PGD 15
#define LHCALL_LOAD_TLS 16
#define LHCALL_NOTIFY 17
#define LHCALL_LOAD_GDT_ENTRY 18
#define LHCALL_SEND_INTERRUPTS 19
#define LGUEST_TRAP_ENTRY 0x1F
......@@ -32,10 +34,10 @@
* operations? There are two ways: the direct way is to make a "hypercall",
* to make requests of the Host Itself.
*
* We use the KVM hypercall mechanism. Eighteen hypercalls are
* We use the KVM hypercall mechanism. Seventeen hypercalls are
* available: the hypercall number is put in the %eax register, and the
* arguments (when required) are placed in %ebx, %ecx and %edx. If a return
* value makes sense, it's returned in %eax.
* arguments (when required) are placed in %ebx, %ecx, %edx and %esi.
* If a return value makes sense, it's returned in %eax.
*
* Grossly invalid calls result in Sudden Death at the hands of the vengeful
* Host, rather than returning failure. This reflects Winston Churchill's
......@@ -47,8 +49,9 @@
#define LHCALL_RING_SIZE 64
struct hcall_args {
/* These map directly onto eax, ebx, ecx, edx in struct lguest_regs */
unsigned long arg0, arg1, arg2, arg3;
/* These map directly onto eax, ebx, ecx, edx and esi
* in struct lguest_regs */
unsigned long arg0, arg1, arg2, arg3, arg4;
};
#endif /* !__ASSEMBLY__ */
......
arch/x86/kernel/asm-offsets_32.c
View file @ 7f3591cf
......@@ -126,6 +126,7 @@ void foo(void)
#if defined(CONFIG_LGUEST) || defined(CONFIG_LGUEST_GUEST) || defined(CONFIG_LGUEST_MODULE)
BLANK();
OFFSET(LGUEST_DATA_irq_enabled, lguest_data, irq_enabled);
OFFSET(LGUEST_DATA_irq_pending, lguest_data, irq_pending);
OFFSET(LGUEST_DATA_pgdir, lguest_data, pgdir);
BLANK();
......
arch/x86/lguest/Kconfig
View file @ 7f3591cf
......@@ -2,7 +2,6 @@ config LGUEST_GUEST
bool "Lguest guest support"
select PARAVIRT
depends on X86_32
depends on !X86_PAE
select VIRTIO
select VIRTIO_RING
select VIRTIO_CONSOLE
......
arch/x86/lguest/boot.c
View file @ 7f3591cf
......@@ -87,7 +87,7 @@ struct lguest_data lguest_data = {
/*G:037 async_hcall() is pretty simple: I'm quite proud of it really. We have a
* ring buffer of stored hypercalls which the Host will run though next time we
* do a normal hypercall. Each entry in the ring has 4 slots for the hypercall
* do a normal hypercall. Each entry in the ring has 5 slots for the hypercall
* arguments, and a "hcall_status" word which is 0 if the call is ready to go,
* and 255 once the Host has finished with it.
*
......@@ -96,7 +96,8 @@ struct lguest_data lguest_data = {
* effect of causing the Host to run all the stored calls in the ring buffer
* which empties it for next time! */
static void async_hcall(unsigned long call, unsigned long arg1,
unsigned long arg2, unsigned long arg3)
unsigned long arg2, unsigned long arg3,
unsigned long arg4)
{
/* Note: This code assumes we're uniprocessor. */
static unsigned int next_call;
......@@ -108,12 +109,13 @@ static void async_hcall(unsigned long call, unsigned long arg1,
local_irq_save(flags);
if (lguest_data.hcall_status[next_call] != 0xFF) {
/* Table full, so do normal hcall which will flush table. */
kvm_hypercall3(call, arg1, arg2, arg3);
kvm_hypercall4(call, arg1, arg2, arg3, arg4);
} else {
lguest_data.hcalls[next_call].arg0 = call;
lguest_data.hcalls[next_call].arg1 = arg1;
lguest_data.hcalls[next_call].arg2 = arg2;
lguest_data.hcalls[next_call].arg3 = arg3;
lguest_data.hcalls[next_call].arg4 = arg4;
/* Arguments must all be written before we mark it to go */
wmb();
lguest_data.hcall_status[next_call] = 0;
......@@ -141,7 +143,7 @@ static void lazy_hcall1(unsigned long call,
if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE)
kvm_hypercall1(call, arg1);
else
async_hcall(call, arg1, 0, 0);
async_hcall(call, arg1, 0, 0, 0);
}
static void lazy_hcall2(unsigned long call,
......@@ -151,7 +153,7 @@ static void lazy_hcall2(unsigned long call,
if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE)
kvm_hypercall2(call, arg1, arg2);
else
async_hcall(call, arg1, arg2, 0);
async_hcall(call, arg1, arg2, 0, 0);
}
static void lazy_hcall3(unsigned long call,
......@@ -162,9 +164,23 @@ static void lazy_hcall3(unsigned long call,
if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE)
kvm_hypercall3(call, arg1, arg2, arg3);
else
async_hcall(call, arg1, arg2, arg3);
async_hcall(call, arg1, arg2, arg3, 0);
}
#ifdef CONFIG_X86_PAE
static void lazy_hcall4(unsigned long call,
unsigned long arg1,
unsigned long arg2,
unsigned long arg3,
unsigned long arg4)
{
if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE)
kvm_hypercall4(call, arg1, arg2, arg3, arg4);
else
async_hcall(call, arg1, arg2, arg3, arg4);
}
#endif
/* When lazy mode is turned off reset the per-cpu lazy mode variable and then
* issue the do-nothing hypercall to flush any stored calls. */
static void lguest_leave_lazy_mmu_mode(void)
......@@ -179,7 +195,7 @@ static void lguest_end_context_switch(struct task_struct *next)
paravirt_end_context_switch(next);
}
/*G:033
/*G:032
* After that diversion we return to our first native-instruction
* replacements: four functions for interrupt control.
*
......@@ -199,30 +215,28 @@ static unsigned long save_fl(void)
{
return lguest_data.irq_enabled;
}
PV_CALLEE_SAVE_REGS_THUNK(save_fl);
/* restore_flags() just sets the flags back to the value given. */
static void restore_fl(unsigned long flags)
{
lguest_data.irq_enabled = flags;
}
PV_CALLEE_SAVE_REGS_THUNK(restore_fl);
/* Interrupts go off... */
static void irq_disable(void)
{
lguest_data.irq_enabled = 0;
}
/* Let's pause a moment. Remember how I said these are called so often?
* Jeremy Fitzhardinge optimized them so hard early in 2009 that he had to
* break some rules. In particular, these functions are assumed to save their
* own registers if they need to: normal C functions assume they can trash the
* eax register. To use normal C functions, we use
* PV_CALLEE_SAVE_REGS_THUNK(), which pushes %eax onto the stack, calls the
* C function, then restores it. */
PV_CALLEE_SAVE_REGS_THUNK(save_fl);
PV_CALLEE_SAVE_REGS_THUNK(irq_disable);
/*:*/
/* Interrupts go on... */
static void irq_enable(void)
{
lguest_data.irq_enabled = X86_EFLAGS_IF;
}
PV_CALLEE_SAVE_REGS_THUNK(irq_enable);
/* These are in i386_head.S */
extern void lg_irq_enable(void);
extern void lg_restore_fl(unsigned long flags);
/*:*/
/*M:003 Note that we don't check for outstanding interrupts when we re-enable
* them (or when we unmask an interrupt). This seems to work for the moment,
* since interrupts are rare and we'll just get the interrupt on the next timer
......@@ -368,8 +382,8 @@ static void lguest_cpuid(unsigned int *ax, unsigned int *bx,
case 1: /* Basic feature request. */
/* We only allow kernel to see SSE3, CMPXCHG16B and SSSE3 */
*cx &= 0x00002201;
/* SSE, SSE2, FXSR, MMX, CMOV, CMPXCHG8B, TSC, FPU. */
*dx &= 0x07808111;
/* SSE, SSE2, FXSR, MMX, CMOV, CMPXCHG8B, TSC, FPU, PAE. */
*dx &= 0x07808151;
/* The Host can do a nice optimization if it knows that the
* kernel mappings (addresses above 0xC0000000 or whatever
* PAGE_OFFSET is set to) haven't changed. But Linux calls
......@@ -388,6 +402,11 @@ static void lguest_cpuid(unsigned int *ax, unsigned int *bx,
if (*ax > 0x80000008)
*ax = 0x80000008;
break;
case 0x80000001:
/* Here we should fix nx cap depending on host. */
/* For this version of PAE, we just clear NX bit. */
*dx &= ~(1 << 20);
break;
}
}
......@@ -521,25 +540,52 @@ static void lguest_write_cr4(unsigned long val)
static void lguest_pte_update(struct mm_struct *mm, unsigned long addr,
pte_t *ptep)
{
#ifdef CONFIG_X86_PAE
lazy_hcall4(LHCALL_SET_PTE, __pa(mm->pgd), addr,
ptep->pte_low, ptep->pte_high);
#else
lazy_hcall3(LHCALL_SET_PTE, __pa(mm->pgd), addr, ptep->pte_low);
#endif
}
static void lguest_set_pte_at(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, pte_t pteval)
{
*ptep = pteval;
native_set_pte(ptep, pteval);
lguest_pte_update(mm, addr, ptep);
}
/* The Guest calls this to set a top-level entry. Again, we set the entry then
* tell the Host which top-level page we changed, and the index of the entry we
* changed. */
/* The Guest calls lguest_set_pud to set a top-level entry and lguest_set_pmd
* to set a middle-level entry when PAE is activated.
* Again, we set the entry then tell the Host which page we changed,
* and the index of the entry we changed. */
#ifdef CONFIG_X86_PAE
static void lguest_set_pud(pud_t *pudp, pud_t pudval)
{
native_set_pud(pudp, pudval);
/* 32 bytes aligned pdpt address and the index. */
lazy_hcall2(LHCALL_SET_PGD, __pa(pudp) & 0xFFFFFFE0,
(__pa(pudp) & 0x1F) / sizeof(pud_t));
}
static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval)
{
*pmdp = pmdval;
native_set_pmd(pmdp, pmdval);
lazy_hcall2(LHCALL_SET_PMD, __pa(pmdp) & PAGE_MASK,
(__pa(pmdp) & (PAGE_SIZE - 1)) / 4);
(__pa(pmdp) & (PAGE_SIZE - 1)) / sizeof(pmd_t));
}
#else
/* The Guest calls lguest_set_pmd to set a top-level entry when PAE is not
* activated. */
static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval)
{
native_set_pmd(pmdp, pmdval);
lazy_hcall2(LHCALL_SET_PGD, __pa(pmdp) & PAGE_MASK,
(__pa(pmdp) & (PAGE_SIZE - 1)) / sizeof(pmd_t));
}
#endif
/* There are a couple of legacy places where the kernel sets a PTE, but we
* don't know the top level any more. This is useless for us, since we don't
......@@ -552,11 +598,31 @@ static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval)
* which brings boot back to 0.25 seconds. */
static void lguest_set_pte(pte_t *ptep, pte_t pteval)
{
*ptep = pteval;
native_set_pte(ptep, pteval);
if (cr3_changed)
lazy_hcall1(LHCALL_FLUSH_TLB, 1);
}
#ifdef CONFIG_X86_PAE
static void lguest_set_pte_atomic(pte_t *ptep, pte_t pte)
{
native_set_pte_atomic(ptep, pte);
if (cr3_changed)
lazy_hcall1(LHCALL_FLUSH_TLB, 1);
}
void lguest_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
{
native_pte_clear(mm, addr, ptep);
lguest_pte_update(mm, addr, ptep);
}
void lguest_pmd_clear(pmd_t *pmdp)
{
lguest_set_pmd(pmdp, __pmd(0));
}
#endif
/* Unfortunately for Lguest, the pv_mmu_ops for page tables were based on
* native page table operations. On native hardware you can set a new page
* table entry whenever you want, but if you want to remove one you have to do
......@@ -628,13 +694,12 @@ static void __init lguest_init_IRQ(void)
{
unsigned int i;
for (i = 0; i < LGUEST_IRQS; i++) {
int vector = FIRST_EXTERNAL_VECTOR + i;
for (i = FIRST_EXTERNAL_VECTOR; i < NR_VECTORS; i++) {
/* Some systems map "vectors" to interrupts weirdly. Lguest has
* a straightforward 1 to 1 mapping, so force that here. */
__get_cpu_var(vector_irq)[vector] = i;
if (vector != SYSCALL_VECTOR)
set_intr_gate(vector, interrupt[i]);
__get_cpu_var(vector_irq)[i] = i - FIRST_EXTERNAL_VECTOR;
if (i != SYSCALL_VECTOR)
set_intr_gate(i, interrupt[i - FIRST_EXTERNAL_VECTOR]);
}
/* This call is required to set up for 4k stacks, where we have
* separate stacks for hard and soft interrupts. */
......@@ -973,10 +1038,10 @@ static void lguest_restart(char *reason)
*
* Our current solution is to allow the paravirt back end to optionally patch
* over the indirect calls to replace them with something more efficient. We
* patch the four most commonly called functions: disable interrupts, enable
* interrupts, restore interrupts and save interrupts. We usually have 6 or 10
* bytes to patch into: the Guest versions of these operations are small enough
* that we can fit comfortably.
* patch two of the simplest of the most commonly called functions: disable
* interrupts and save interrupts. We usually have 6 or 10 bytes to patch
* into: the Guest versions of these operations are small enough that we can
* fit comfortably.
*
* First we need assembly templates of each of the patchable Guest operations,
* and these are in i386_head.S. */
......@@ -987,8 +1052,6 @@ static const struct lguest_insns
const char *start, *end;
} lguest_insns[] = {
[PARAVIRT_PATCH(pv_irq_ops.irq_disable)] = { lgstart_cli, lgend_cli },
[PARAVIRT_PATCH(pv_irq_ops.irq_enable)] = { lgstart_sti, lgend_sti },
[PARAVIRT_PATCH(pv_irq_ops.restore_fl)] = { lgstart_popf, lgend_popf },
[PARAVIRT_PATCH(pv_irq_ops.save_fl)] = { lgstart_pushf, lgend_pushf },
};
......@@ -1026,6 +1089,7 @@ __init void lguest_init(void)
pv_info.name = "lguest";
pv_info.paravirt_enabled = 1;
pv_info.kernel_rpl = 1;
pv_info.shared_kernel_pmd = 1;
/* We set up all the lguest overrides for sensitive operations. These
* are detailed with the operations themselves. */
......@@ -1033,9 +1097,9 @@ __init void lguest_init(void)
/* interrupt-related operations */
pv_irq_ops.init_IRQ = lguest_init_IRQ;
pv_irq_ops.save_fl = PV_CALLEE_SAVE(save_fl);
pv_irq_ops.restore_fl = PV_CALLEE_SAVE(restore_fl);
pv_irq_ops.restore_fl = __PV_IS_CALLEE_SAVE(lg_restore_fl);
pv_irq_ops.irq_disable = PV_CALLEE_SAVE(irq_disable);
pv_irq_ops.irq_enable = PV_CALLEE_SAVE(irq_enable);
pv_irq_ops.irq_enable = __PV_IS_CALLEE_SAVE(lg_irq_enable);
pv_irq_ops.safe_halt = lguest_safe_halt;
/* init-time operations */
......@@ -1071,6 +1135,12 @@ __init void lguest_init(void)
pv_mmu_ops.set_pte = lguest_set_pte;
pv_mmu_ops.set_pte_at = lguest_set_pte_at;
pv_mmu_ops.set_pmd = lguest_set_pmd;
#ifdef CONFIG_X86_PAE
pv_mmu_ops.set_pte_atomic = lguest_set_pte_atomic;
pv_mmu_ops.pte_clear = lguest_pte_clear;
pv_mmu_ops.pmd_clear = lguest_pmd_clear;
pv_mmu_ops.set_pud = lguest_set_pud;
#endif
pv_mmu_ops.read_cr2 = lguest_read_cr2;
pv_mmu_ops.read_cr3 = lguest_read_cr3;
pv_mmu_ops.lazy_mode.enter = paravirt_enter_lazy_mmu;
......
arch/x86/lguest/i386_head.S
View file @ 7f3591cf
......@@ -46,10 +46,64 @@ ENTRY(lguest_entry)
.globl lgstart_##name; .globl lgend_##name
LGUEST_PATCH(cli, movl $0, lguest_data+LGUEST_DATA_irq_enabled)
LGUEST_PATCH(sti, movl $X86_EFLAGS_IF, lguest_data+LGUEST_DATA_irq_enabled)
LGUEST_PATCH(popf, movl %eax, lguest_data+LGUEST_DATA_irq_enabled)
LGUEST_PATCH(pushf, movl lguest_data+LGUEST_DATA_irq_enabled, %eax)
/*:*/
/*G:033 But using those wrappers is inefficient (we'll see why that doesn't
* matter for save_fl and irq_disable later). If we write our routines
* carefully in assembler, we can avoid clobbering any registers and avoid
* jumping through the wrapper functions.
*
* I skipped over our first piece of assembler, but this one is worth studying
* in a bit more detail so I'll describe in easy stages. First, the routine
* to enable interrupts: */
ENTRY(lg_irq_enable)
/* The reverse of irq_disable, this sets lguest_data.irq_enabled to
* X86_EFLAGS_IF (ie. "Interrupts enabled"). */
movl $X86_EFLAGS_IF, lguest_data+LGUEST_DATA_irq_enabled
/* But now we need to check if the Host wants to know: there might have
* been interrupts waiting to be delivered, in which case it will have
* set lguest_data.irq_pending to X86_EFLAGS_IF. If it's not zero, we
* jump to send_interrupts, otherwise we're done. */
testl $0, lguest_data+LGUEST_DATA_irq_pending
jnz send_interrupts
/* One cool thing about x86 is that you can do many things without using
* a register. In this case, the normal path hasn't needed to save or
* restore any registers at all! */
ret
send_interrupts:
/* OK, now we need a register: eax is used for the hypercall number,
* which is LHCALL_SEND_INTERRUPTS.
*
* We used not to bother with this pending detection at all, which was
* much simpler. Sooner or later the Host would realize it had to
* send us an interrupt. But that turns out to make performance 7
* times worse on a simple tcp benchmark. So now we do this the hard
* way. */
pushl %eax
movl $LHCALL_SEND_INTERRUPTS, %eax
/* This is a vmcall instruction (same thing that KVM uses). Older
* assembler versions might not know the "vmcall" instruction, so we
* create one manually here. */
.byte 0x0f,0x01,0xc1 /* KVM_HYPERCALL */
popl %eax
ret
/* Finally, the "popf" or "restore flags" routine. The %eax register holds the
* flags (in practice, either X86_EFLAGS_IF or 0): if it's X86_EFLAGS_IF we're
* enabling interrupts again, if it's 0 we're leaving them off. */
ENTRY(lg_restore_fl)
/* This is just "lguest_data.irq_enabled = flags;" */
movl %eax, lguest_data+LGUEST_DATA_irq_enabled
/* Now, if the %eax value has enabled interrupts and
* lguest_data.irq_pending is set, we want to tell the Host so it can
* deliver any outstanding interrupts. Fortunately, both values will
* be X86_EFLAGS_IF (ie. 512) in that case, and the "testl"
* instruction will AND them together for us. If both are set, we
* jump to send_interrupts. */
testl lguest_data+LGUEST_DATA_irq_pending, %eax
jnz send_interrupts
/* Again, the normal path has used no extra registers. Clever, huh? */
ret
/* These demark the EIP range where host should never deliver interrupts. */
.global lguest_noirq_start
......
drivers/lguest/Kconfig
View file @ 7f3591cf
config LGUEST
tristate "Linux hypervisor example code"
depends on X86_32 && EXPERIMENTAL && !X86_PAE && FUTEX
depends on X86_32 && EXPERIMENTAL && EVENTFD
select HVC_DRIVER
---help---
This is a very simple module which allows you to run
......
drivers/lguest/core.c
View file @ 7f3591cf
......@@ -95,7 +95,7 @@ static __init int map_switcher(void)
* array of struct pages. It increments that pointer, but we don't
* care. */
pagep = switcher_page;
err = map_vm_area(switcher_vma, PAGE_KERNEL, &pagep);
err = map_vm_area(switcher_vma, PAGE_KERNEL_EXEC, &pagep);
if (err) {
printk("lguest: map_vm_area failed: %i\n", err);
goto free_vma;
......@@ -188,6 +188,9 @@ int run_guest(struct lg_cpu *cpu, unsigned long __user *user)
{
/* We stop running once the Guest is dead. */
while (!cpu->lg->dead) {
unsigned int irq;
bool more;
/* First we run any hypercalls the Guest wants done. */
if (cpu->hcall)
do_hypercalls(cpu);
......@@ -195,23 +198,23 @@ int run_guest(struct lg_cpu *cpu, unsigned long __user *user)
/* It's possible the Guest did a NOTIFY hypercall to the
* Launcher, in which case we return from the read() now. */
if (cpu->pending_notify) {
if (!send_notify_to_eventfd(cpu)) {
if (put_user(cpu->pending_notify, user))
return -EFAULT;
return sizeof(cpu->pending_notify);
}
}
/* Check for signals */
if (signal_pending(current))
return -ERESTARTSYS;
/* If Waker set break_out, return to Launcher. */
if (cpu->break_out)
return -EAGAIN;
/* Check if there are any interrupts which can be delivered now:
* if so, this sets up the hander to be executed when we next
* run the Guest. */
maybe_do_interrupt(cpu);
irq = interrupt_pending(cpu, &more);
if (irq < LGUEST_IRQS)
try_deliver_interrupt(cpu, irq, more);
/* All long-lived kernel loops need to check with this horrible
* thing called the freezer. If the Host is trying to suspend,
......@@ -224,9 +227,14 @@ int run_guest(struct lg_cpu *cpu, unsigned long __user *user)
break;
/* If the Guest asked to be stopped, we sleep. The Guest's
* clock timer or LHREQ_BREAK from the Waker will wake us. */
* clock timer will wake us. */
if (cpu->halted) {
set_current_state(TASK_INTERRUPTIBLE);
/* Just before we sleep, make sure no interrupt snuck in
* which we should be doing. */
if (interrupt_pending(cpu, &more) < LGUEST_IRQS)
set_current_state(TASK_RUNNING);
else
schedule();
continue;
}
......
drivers/lguest/hypercalls.c
View file @ 7f3591cf
......@@ -37,6 +37,10 @@ static void do_hcall(struct lg_cpu *cpu, struct hcall_args *args)
/* This call does nothing, except by breaking out of the Guest
* it makes us process all the asynchronous hypercalls. */
break;
case LHCALL_SEND_INTERRUPTS:
/* This call does nothing too, but by breaking out of the Guest
* it makes us process any pending interrupts. */
break;
case LHCALL_LGUEST_INIT:
/* You can't get here unless you're already initialized. Don't
* do that. */
......@@ -73,11 +77,21 @@ static void do_hcall(struct lg_cpu *cpu, struct hcall_args *args)
guest_set_stack(cpu, args->arg1, args->arg2, args->arg3);
break;
case LHCALL_SET_PTE:
#ifdef CONFIG_X86_PAE
guest_set_pte(cpu, args->arg1, args->arg2,
__pte(args->arg3 | (u64)args->arg4 << 32));
#else
guest_set_pte(cpu, args->arg1, args->arg2, __pte(args->arg3));
#endif
break;
case LHCALL_SET_PGD:
guest_set_pgd(cpu->lg, args->arg1, args->arg2);
break;
#ifdef CONFIG_X86_PAE
case LHCALL_SET_PMD:
guest_set_pmd(cpu->lg, args->arg1, args->arg2);
break;
#endif
case LHCALL_SET_CLOCKEVENT:
guest_set_clockevent(cpu, args->arg1);
break;
......
drivers/lguest/interrupts_and_traps.c
View file @ 7f3591cf
......@@ -128,30 +128,39 @@ static void set_guest_interrupt(struct lg_cpu *cpu, u32 lo, u32 hi,
/*H:205
* Virtual Interrupts.
*
* maybe_do_interrupt() gets called before every entry to the Guest, to see if
* we should divert the Guest to running an interrupt handler. */
void maybe_do_interrupt(struct lg_cpu *cpu)
* interrupt_pending() returns the first pending interrupt which isn't blocked
* by the Guest. It is called before every entry to the Guest, and just before
* we go to sleep when the Guest has halted itself. */
unsigned int interrupt_pending(struct lg_cpu *cpu, bool *more)
{
unsigned int irq;
DECLARE_BITMAP(blk, LGUEST_IRQS);
struct desc_struct *idt;
/* If the Guest hasn't even initialized yet, we can do nothing. */
if (!cpu->lg->lguest_data)
return;
return LGUEST_IRQS;
/* Take our "irqs_pending" array and remove any interrupts the Guest
* wants blocked: the result ends up in "blk". */
if (copy_from_user(&blk, cpu->lg->lguest_data->blocked_interrupts,
sizeof(blk)))
return;
return LGUEST_IRQS;
bitmap_andnot(blk, cpu->irqs_pending, blk, LGUEST_IRQS);
/* Find the first interrupt. */
irq = find_first_bit(blk, LGUEST_IRQS);
/* None? Nothing to do */
if (irq >= LGUEST_IRQS)
return;
*more = find_next_bit(blk, LGUEST_IRQS, irq+1);
return irq;
}
/* This actually diverts the Guest to running an interrupt handler, once an
* interrupt has been identified by interrupt_pending(). */
void try_deliver_interrupt(struct lg_cpu *cpu, unsigned int irq, bool more)
{
struct desc_struct *idt;
BUG_ON(irq >= LGUEST_IRQS);
/* They may be in the middle of an iret, where they asked us never to
* deliver interrupts. */
......@@ -170,9 +179,13 @@ void maybe_do_interrupt(struct lg_cpu *cpu)
u32 irq_enabled;
if (get_user(irq_enabled, &cpu->lg->lguest_data->irq_enabled))
irq_enabled = 0;
if (!irq_enabled)
if (!irq_enabled) {
/* Make sure they know an IRQ is pending. */
put_user(X86_EFLAGS_IF,
&cpu->lg->lguest_data->irq_pending);
return;
}
}
/* Look at the IDT entry the Guest gave us for this interrupt. The
* first 32 (FIRST_EXTERNAL_VECTOR) entries are for traps, so we skip
......@@ -194,6 +207,25 @@ void maybe_do_interrupt(struct lg_cpu *cpu)
* here is a compromise which means at least it gets updated every
* timer interrupt. */
write_timestamp(cpu);
/* If there are no other interrupts we want to deliver, clear
* the pending flag. */
if (!more)
put_user(0, &cpu->lg->lguest_data->irq_pending);
}
/* And this is the routine when we want to set an interrupt for the Guest. */
void set_interrupt(struct lg_cpu *cpu, unsigned int irq)
{
/* Next time the Guest runs, the core code will see if it can deliver
* this interrupt. */
set_bit(irq, cpu->irqs_pending);
/* Make sure it sees it; it might be asleep (eg. halted), or
* running the Guest right now, in which case kick_process()
* will knock it out. */
if (!wake_up_process(cpu->tsk))
kick_process(cpu->tsk);
}
/*:*/
......@@ -510,10 +542,7 @@ static enum hrtimer_restart clockdev_fn(struct hrtimer *timer)
struct lg_cpu *cpu = container_of(timer, struct lg_cpu, hrt);
/* Remember the first interrupt is the timer interrupt. */
set_bit(0, cpu->irqs_pending);
/* If the Guest is actually stopped, we need to wake it up. */
if (cpu->halted)
wake_up_process(cpu->tsk);
set_interrupt(cpu, 0);
return HRTIMER_NORESTART;
}
......
drivers/lguest/lg.h
View file @ 7f3591cf
......@@ -49,7 +49,7 @@ struct lg_cpu {
u32 cr2;
int ts;
u32 esp1;
u8 ss1;
u16 ss1;
/* Bitmap of what has changed: see CHANGED_* above. */
int changed;
......@@ -71,9 +71,7 @@ struct lg_cpu {
/* Virtual clock device */
struct hrtimer hrt;
/* Do we need to stop what we're doing and return to userspace? */
int break_out;
wait_queue_head_t break_wq;
/* Did the Guest tell us to halt? */
int halted;
/* Pending virtual interrupts */
......@@ -82,6 +80,16 @@ struct lg_cpu {
struct lg_cpu_arch arch;
};
struct lg_eventfd {
unsigned long addr;
struct file *event;
};
struct lg_eventfd_map {
unsigned int num;
struct lg_eventfd map[];
};
/* The private info the thread maintains about the guest. */
struct lguest
{
......@@ -102,6 +110,8 @@ struct lguest
unsigned int stack_pages;
u32 tsc_khz;
struct lg_eventfd_map *eventfds;
/* Dead? */
const char *dead;
};
......@@ -137,9 +147,13 @@ int run_guest(struct lg_cpu *cpu, unsigned long __user *user);
* in the kernel. */
#define pgd_flags(x) (pgd_val(x) & ~PAGE_MASK)
#define pgd_pfn(x) (pgd_val(x) >> PAGE_SHIFT)
#define pmd_flags(x) (pmd_val(x) & ~PAGE_MASK)
#define pmd_pfn(x) (pmd_val(x) >> PAGE_SHIFT)
/* interrupts_and_traps.c: */
void maybe_do_interrupt(struct lg_cpu *cpu);
unsigned int interrupt_pending(struct lg_cpu *cpu, bool *more);
void try_deliver_interrupt(struct lg_cpu *cpu, unsigned int irq, bool more);
void set_interrupt(struct lg_cpu *cpu, unsigned int irq);
bool deliver_trap(struct lg_cpu *cpu, unsigned int num);
void load_guest_idt_entry(struct lg_cpu *cpu, unsigned int i,
u32 low, u32 hi);
......@@ -150,6 +164,7 @@ void setup_default_idt_entries(struct lguest_ro_state *state,
void copy_traps(const struct lg_cpu *cpu, struct desc_struct *idt,
const unsigned long *def);
void guest_set_clockevent(struct lg_cpu *cpu, unsigned long delta);
bool send_notify_to_eventfd(struct lg_cpu *cpu);
void init_clockdev(struct lg_cpu *cpu);
bool check_syscall_vector(struct lguest *lg);
int init_interrupts(void);
......@@ -168,7 +183,10 @@ void copy_gdt_tls(const struct lg_cpu *cpu, struct desc_struct *gdt);
int init_guest_pagetable(struct lguest *lg);
void free_guest_pagetable(struct lguest *lg);
void guest_new_pagetable(struct lg_cpu *cpu, unsigned long pgtable);
void guest_set_pgd(struct lguest *lg, unsigned long gpgdir, u32 i);
#ifdef CONFIG_X86_PAE
void guest_set_pmd(struct lguest *lg, unsigned long gpgdir, u32 i);
#endif
void guest_pagetable_clear_all(struct lg_cpu *cpu);
void guest_pagetable_flush_user(struct lg_cpu *cpu);
void guest_set_pte(struct lg_cpu *cpu, unsigned long gpgdir,
......
drivers/lguest/lguest_user.c
View file @ 7f3591cf
......@@ -7,32 +7,83 @@
#include <linux/miscdevice.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/eventfd.h>
#include <linux/file.h>
#include "lg.h"
/*L:055 When something happens, the Waker process needs a way to stop the
* kernel running the Guest and return to the Launcher. So the Waker writes
* LHREQ_BREAK and the value "1" to /dev/lguest to do this. Once the Launcher
* has done whatever needs attention, it writes LHREQ_BREAK and "0" to release
* the Waker. */
static int break_guest_out(struct lg_cpu *cpu, const unsigned long __user*input)
bool send_notify_to_eventfd(struct lg_cpu *cpu)
{
unsigned long on;
unsigned int i;
struct lg_eventfd_map *map;
/* lg->eventfds is RCU-protected */
rcu_read_lock();
map = rcu_dereference(cpu->lg->eventfds);
for (i = 0; i < map->num; i++) {
if (map->map[i].addr == cpu->pending_notify) {
eventfd_signal(map->map[i].event, 1);
cpu->pending_notify = 0;
break;
}
}
rcu_read_unlock();
return cpu->pending_notify == 0;
}
static int add_eventfd(struct lguest *lg, unsigned long addr, int fd)
{
struct lg_eventfd_map *new, *old = lg->eventfds;
if (!addr)
return -EINVAL;
/* Replace the old array with the new one, carefully: others can
* be accessing it at the same time */
new = kmalloc(sizeof(*new) + sizeof(new->map[0]) * (old->num + 1),
GFP_KERNEL);
if (!new)
return -ENOMEM;
/* First make identical copy. */
memcpy(new->map, old->map, sizeof(old->map[0]) * old->num);
new->num = old->num;
/* Now append new entry. */
new->map[new->num].addr = addr;
new->map[new->num].event = eventfd_fget(fd);
if (IS_ERR(new->map[new->num].event)) {
kfree(new);
return PTR_ERR(new->map[new->num].event);
}
new->num++;
/* Now put new one in place. */
rcu_assign_pointer(lg->eventfds, new);
/* We're not in a big hurry. Wait until noone's looking at old
* version, then delete it. */
synchronize_rcu();
kfree(old);
return 0;
}
/* Fetch whether they're turning break on or off. */
if (get_user(on, input) != 0)
static int attach_eventfd(struct lguest *lg, const unsigned long __user *input)
{
unsigned long addr, fd;
int err;
if (get_user(addr, input) != 0)
return -EFAULT;
input++;
if (get_user(fd, input) != 0)
return -EFAULT;
if (on) {
cpu->break_out = 1;
/* Pop it out of the Guest (may be running on different CPU) */
wake_up_process(cpu->tsk);
/* Wait for them to reset it */
return wait_event_interruptible(cpu->break_wq, !cpu->break_out);
} else {
cpu->break_out = 0;
wake_up(&cpu->break_wq);
mutex_lock(&lguest_lock);
err = add_eventfd(lg, addr, fd);
mutex_unlock(&lguest_lock);
return 0;
}
}
/*L:050 Sending an interrupt is done by writing LHREQ_IRQ and an interrupt
......@@ -45,9 +96,8 @@ static int user_send_irq(struct lg_cpu *cpu, const unsigned long __user *input)
return -EFAULT;
if (irq >= LGUEST_IRQS)
return -EINVAL;
/* Next time the Guest runs, the core code will see if it can deliver
* this interrupt. */
set_bit(irq, cpu->irqs_pending);
set_interrupt(cpu, irq);
return 0;
}
......@@ -126,9 +176,6 @@ static int lg_cpu_start(struct lg_cpu *cpu, unsigned id, unsigned long start_ip)
* address. */
lguest_arch_setup_regs(cpu, start_ip);
/* Initialize the queue for the Waker to wait on */
init_waitqueue_head(&cpu->break_wq);
/* We keep a pointer to the Launcher task (ie. current task) for when
* other Guests want to wake this one (eg. console input). */
cpu->tsk = current;
......@@ -185,6 +232,13 @@ static int initialize(struct file *file, const unsigned long __user *input)
goto unlock;
}
lg->eventfds = kmalloc(sizeof(*lg->eventfds), GFP_KERNEL);
if (!lg->eventfds) {
err = -ENOMEM;
goto free_lg;
}
lg->eventfds->num = 0;
/* Populate the easy fields of our "struct lguest" */
lg->mem_base = (void __user *)args[0];
lg->pfn_limit = args[1];
......@@ -192,7 +246,7 @@ static int initialize(struct file *file, const unsigned long __user *input)
/* This is the first cpu (cpu 0) and it will start booting at args[2] */
err = lg_cpu_start(&lg->cpus[0], 0, args[2]);
if (err)
goto release_guest;
goto free_eventfds;
/* Initialize the Guest's shadow page tables, using the toplevel
* address the Launcher gave us. This allocates memory, so can fail. */
......@@ -211,7 +265,9 @@ static int initialize(struct file *file, const unsigned long __user *input)
free_regs:
/* FIXME: This should be in free_vcpu */
free_page(lg->cpus[0].regs_page);
release_guest:
free_eventfds:
kfree(lg->eventfds);
free_lg:
kfree(lg);
unlock:
mutex_unlock(&lguest_lock);
......@@ -252,11 +308,6 @@ static ssize_t write(struct file *file, const char __user *in,
/* Once the Guest is dead, you can only read() why it died. */
if (lg->dead)
return -ENOENT;
/* If you're not the task which owns the Guest, all you can do
* is break the Launcher out of running the Guest. */
if (current != cpu->tsk && req != LHREQ_BREAK)
return -EPERM;
}
switch (req) {
......@@ -264,8 +315,8 @@ static ssize_t write(struct file *file, const char __user *in,
return initialize(file, input);
case LHREQ_IRQ:
return user_send_irq(cpu, input);
case LHREQ_BREAK:
return break_guest_out(cpu, input);
case LHREQ_EVENTFD:
return attach_eventfd(lg, input);
default:
return -EINVAL;
}
......@@ -303,6 +354,12 @@ static int close(struct inode *inode, struct file *file)
* the Launcher's memory management structure. */
mmput(lg->cpus[i].mm);
}
/* Release any eventfds they registered. */
for (i = 0; i < lg->eventfds->num; i++)
fput(lg->eventfds->map[i].event);
kfree(lg->eventfds);
/* If lg->dead doesn't contain an error code it will be NULL or a
* kmalloc()ed string, either of which is ok to hand to kfree(). */
if (!IS_ERR(lg->dead))
......
drivers/lguest/page_tables.c
View file @ 7f3591cf
......@@ -53,6 +53,17 @@
* page. */
#define SWITCHER_PGD_INDEX (PTRS_PER_PGD - 1)
/* For PAE we need the PMD index as well. We use the last 2MB, so we
* will need the last pmd entry of the last pmd page. */
#ifdef CONFIG_X86_PAE
#define SWITCHER_PMD_INDEX (PTRS_PER_PMD - 1)
#define RESERVE_MEM 2U
#define CHECK_GPGD_MASK _PAGE_PRESENT
#else
#define RESERVE_MEM 4U
#define CHECK_GPGD_MASK _PAGE_TABLE
#endif
/* We actually need a separate PTE page for each CPU. Remember that after the
* Switcher code itself comes two pages for each CPU, and we don't want this
* CPU's guest to see the pages of any other CPU. */
......@@ -73,24 +84,59 @@ static pgd_t *spgd_addr(struct lg_cpu *cpu, u32 i, unsigned long vaddr)
{
unsigned int index = pgd_index(vaddr);
#ifndef CONFIG_X86_PAE
/* We kill any Guest trying to touch the Switcher addresses. */
if (index >= SWITCHER_PGD_INDEX) {
kill_guest(cpu, "attempt to access switcher pages");
index = 0;
}
#endif
/* Return a pointer index'th pgd entry for the i'th page table. */
return &cpu->lg->pgdirs[i].pgdir[index];
}
#ifdef CONFIG_X86_PAE
/* This routine then takes the PGD entry given above, which contains the
* address of the PMD page. It then returns a pointer to the PMD entry for the
* given address. */
static pmd_t *spmd_addr(struct lg_cpu *cpu, pgd_t spgd, unsigned long vaddr)
{
unsigned int index = pmd_index(vaddr);
pmd_t *page;
/* We kill any Guest trying to touch the Switcher addresses. */
if (pgd_index(vaddr) == SWITCHER_PGD_INDEX &&
index >= SWITCHER_PMD_INDEX) {
kill_guest(cpu, "attempt to access switcher pages");
index = 0;
}
/* You should never call this if the PGD entry wasn't valid */
BUG_ON(!(pgd_flags(spgd) & _PAGE_PRESENT));
page = __va(pgd_pfn(spgd) << PAGE_SHIFT);
return &page[index];
}
#endif
/* This routine then takes the page directory entry returned above, which
* contains the address of the page table entry (PTE) page. It then returns a
* pointer to the PTE entry for the given address. */
static pte_t *spte_addr(pgd_t spgd, unsigned long vaddr)
static pte_t *spte_addr(struct lg_cpu *cpu, pgd_t spgd, unsigned long vaddr)
{
#ifdef CONFIG_X86_PAE
pmd_t *pmd = spmd_addr(cpu, spgd, vaddr);
pte_t *page = __va(pmd_pfn(*pmd) << PAGE_SHIFT);
/* You should never call this if the PMD entry wasn't valid */
BUG_ON(!(pmd_flags(*pmd) & _PAGE_PRESENT));
#else
pte_t *page = __va(pgd_pfn(spgd) << PAGE_SHIFT);
/* You should never call this if the PGD entry wasn't valid */
BUG_ON(!(pgd_flags(spgd) & _PAGE_PRESENT));
return &page[(vaddr >> PAGE_SHIFT) % PTRS_PER_PTE];
#endif
return &page[pte_index(vaddr)];
}
/* These two functions just like the above two, except they access the Guest
......@@ -101,12 +147,32 @@ static unsigned long gpgd_addr(struct lg_cpu *cpu, unsigned long vaddr)
return cpu->lg->pgdirs[cpu->cpu_pgd].gpgdir + index * sizeof(pgd_t);
}
static unsigned long gpte_addr(pgd_t gpgd, unsigned long vaddr)
#ifdef CONFIG_X86_PAE
static unsigned long gpmd_addr(pgd_t gpgd, unsigned long vaddr)
{
unsigned long gpage = pgd_pfn(gpgd) << PAGE_SHIFT;
BUG_ON(!(pgd_flags(gpgd) & _PAGE_PRESENT));
return gpage + pmd_index(vaddr) * sizeof(pmd_t);
}
static unsigned long gpte_addr(struct lg_cpu *cpu,
pmd_t gpmd, unsigned long vaddr)
{
unsigned long gpage = pmd_pfn(gpmd) << PAGE_SHIFT;
BUG_ON(!(pmd_flags(gpmd) & _PAGE_PRESENT));
return gpage + pte_index(vaddr) * sizeof(pte_t);
}
#else
static unsigned long gpte_addr(struct lg_cpu *cpu,
pgd_t gpgd, unsigned long vaddr)
{
unsigned long gpage = pgd_pfn(gpgd) << PAGE_SHIFT;
BUG_ON(!(pgd_flags(gpgd) & _PAGE_PRESENT));
return gpage + ((vaddr>>PAGE_SHIFT) % PTRS_PER_PTE) * sizeof(pte_t);
return gpage + pte_index(vaddr) * sizeof(pte_t);
}
#endif
/*:*/
/*M:014 get_pfn is slow: we could probably try to grab batches of pages here as
......@@ -171,7 +237,7 @@ static void release_pte(pte_t pte)
/* Remember that get_user_pages_fast() took a reference to the page, in
* get_pfn()? We have to put it back now. */
if (pte_flags(pte) & _PAGE_PRESENT)
put_page(pfn_to_page(pte_pfn(pte)));
put_page(pte_page(pte));
}
/*:*/
......@@ -184,11 +250,20 @@ static void check_gpte(struct lg_cpu *cpu, pte_t gpte)
static void check_gpgd(struct lg_cpu *cpu, pgd_t gpgd)
{
if ((pgd_flags(gpgd) & ~_PAGE_TABLE) ||
if ((pgd_flags(gpgd) & ~CHECK_GPGD_MASK) ||
(pgd_pfn(gpgd) >= cpu->lg->pfn_limit))
kill_guest(cpu, "bad page directory entry");
}
#ifdef CONFIG_X86_PAE
static void check_gpmd(struct lg_cpu *cpu, pmd_t gpmd)
{
if ((pmd_flags(gpmd) & ~_PAGE_TABLE) ||
(pmd_pfn(gpmd) >= cpu->lg->pfn_limit))
kill_guest(cpu, "bad page middle directory entry");
}
#endif
/*H:330
* (i) Looking up a page table entry when the Guest faults.
*
......@@ -207,6 +282,11 @@ bool demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode)
pte_t gpte;
pte_t *spte;
#ifdef CONFIG_X86_PAE
pmd_t *spmd;
pmd_t gpmd;
#endif
/* First step: get the top-level Guest page table entry. */
gpgd = lgread(cpu, gpgd_addr(cpu, vaddr), pgd_t);
/* Toplevel not present? We can't map it in. */
......@@ -228,12 +308,45 @@ bool demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode)
check_gpgd(cpu, gpgd);
/* And we copy the flags to the shadow PGD entry. The page
* number in the shadow PGD is the page we just allocated. */
*spgd = __pgd(__pa(ptepage) | pgd_flags(gpgd));
set_pgd(spgd, __pgd(__pa(ptepage) | pgd_flags(gpgd)));
}
#ifdef CONFIG_X86_PAE
gpmd = lgread(cpu, gpmd_addr(gpgd, vaddr), pmd_t);
/* middle level not present? We can't map it in. */
if (!(pmd_flags(gpmd) & _PAGE_PRESENT))
return false;
/* Now look at the matching shadow entry. */
spmd = spmd_addr(cpu, *spgd, vaddr);
if (!(pmd_flags(*spmd) & _PAGE_PRESENT)) {
/* No shadow entry: allocate a new shadow PTE page. */
unsigned long ptepage = get_zeroed_page(GFP_KERNEL);
/* This is not really the Guest's fault, but killing it is
* simple for this corner case. */
if (!ptepage) {
kill_guest(cpu, "out of memory allocating pte page");
return false;
}
/* We check that the Guest pmd is OK. */
check_gpmd(cpu, gpmd);
/* And we copy the flags to the shadow PMD entry. The page
* number in the shadow PMD is the page we just allocated. */
native_set_pmd(spmd, __pmd(__pa(ptepage) | pmd_flags(gpmd)));
}
/* OK, now we look at the lower level in the Guest page table: keep its
* address, because we might update it later. */
gpte_ptr = gpte_addr(cpu, gpmd, vaddr);
#else
/* OK, now we look at the lower level in the Guest page table: keep its
* address, because we might update it later. */
gpte_ptr = gpte_addr(gpgd, vaddr);
gpte_ptr = gpte_addr(cpu, gpgd, vaddr);
#endif
gpte = lgread(cpu, gpte_ptr, pte_t);
/* If this page isn't in the Guest page tables, we can't page it in. */
......@@ -259,7 +372,7 @@ bool demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode)
gpte = pte_mkdirty(gpte);
/* Get the pointer to the shadow PTE entry we're going to set. */
spte = spte_addr(*spgd, vaddr);
spte = spte_addr(cpu, *spgd, vaddr);
/* If there was a valid shadow PTE entry here before, we release it.
* This can happen with a write to a previously read-only entry. */
release_pte(*spte);
......@@ -273,7 +386,7 @@ bool demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode)
* table entry, even if the Guest says it's writable. That way
* we will come back here when a write does actually occur, so
* we can update the Guest's _PAGE_DIRTY flag. */
*spte = gpte_to_spte(cpu, pte_wrprotect(gpte), 0);
native_set_pte(spte, gpte_to_spte(cpu, pte_wrprotect(gpte), 0));
/* Finally, we write the Guest PTE entry back: we've set the
* _PAGE_ACCESSED and maybe the _PAGE_DIRTY flags. */
......@@ -301,14 +414,23 @@ static bool page_writable(struct lg_cpu *cpu, unsigned long vaddr)
pgd_t *spgd;
unsigned long flags;
#ifdef CONFIG_X86_PAE
pmd_t *spmd;
#endif
/* Look at the current top level entry: is it present? */
spgd = spgd_addr(cpu, cpu->cpu_pgd, vaddr);
if (!(pgd_flags(*spgd) & _PAGE_PRESENT))
return false;
#ifdef CONFIG_X86_PAE
spmd = spmd_addr(cpu, *spgd, vaddr);
if (!(pmd_flags(*spmd) & _PAGE_PRESENT))
return false;
#endif
/* Check the flags on the pte entry itself: it must be present and
* writable. */
flags = pte_flags(*(spte_addr(*spgd, vaddr)));
flags = pte_flags(*(spte_addr(cpu, *spgd, vaddr)));
return (flags & (_PAGE_PRESENT|_PAGE_RW)) == (_PAGE_PRESENT|_PAGE_RW);
}
......@@ -322,8 +444,43 @@ void pin_page(struct lg_cpu *cpu, unsigned long vaddr)
kill_guest(cpu, "bad stack page %#lx", vaddr);
}
#ifdef CONFIG_X86_PAE
static void release_pmd(pmd_t *spmd)
{
/* If the entry's not present, there's nothing to release. */
if (pmd_flags(*spmd) & _PAGE_PRESENT) {
unsigned int i;
pte_t *ptepage = __va(pmd_pfn(*spmd) << PAGE_SHIFT);
/* For each entry in the page, we might need to release it. */
for (i = 0; i < PTRS_PER_PTE; i++)
release_pte(ptepage[i]);
/* Now we can free the page of PTEs */
free_page((long)ptepage);
/* And zero out the PMD entry so we never release it twice. */
native_set_pmd(spmd, __pmd(0));
}
}
static void release_pgd(pgd_t *spgd)
{
/* If the entry's not present, there's nothing to release. */
if (pgd_flags(*spgd) & _PAGE_PRESENT) {
unsigned int i;
pmd_t *pmdpage = __va(pgd_pfn(*spgd) << PAGE_SHIFT);
for (i = 0; i < PTRS_PER_PMD; i++)
release_pmd(&pmdpage[i]);
/* Now we can free the page of PMDs */
free_page((long)pmdpage);
/* And zero out the PGD entry so we never release it twice. */
set_pgd(spgd, __pgd(0));
}
}
#else /* !CONFIG_X86_PAE */
/*H:450 If we chase down the release_pgd() code, it looks like this: */
static void release_pgd(struct lguest *lg, pgd_t *spgd)
static void release_pgd(pgd_t *spgd)
{
/* If the entry's not present, there's nothing to release. */
if (pgd_flags(*spgd) & _PAGE_PRESENT) {
......@@ -341,7 +498,7 @@ static void release_pgd(struct lguest *lg, pgd_t *spgd)
*spgd = __pgd(0);
}
}
#endif
/*H:445 We saw flush_user_mappings() twice: once from the flush_user_mappings()
* hypercall and once in new_pgdir() when we re-used a top-level pgdir page.
* It simply releases every PTE page from 0 up to the Guest's kernel address. */
......@@ -350,7 +507,7 @@ static void flush_user_mappings(struct lguest *lg, int idx)
unsigned int i;
/* Release every pgd entry up to the kernel's address. */
for (i = 0; i < pgd_index(lg->kernel_address); i++)
release_pgd(lg, lg->pgdirs[idx].pgdir + i);
release_pgd(lg->pgdirs[idx].pgdir + i);
}
/*H:440 (v) Flushing (throwing away) page tables,
......@@ -369,7 +526,9 @@ unsigned long guest_pa(struct lg_cpu *cpu, unsigned long vaddr)
{
pgd_t gpgd;
pte_t gpte;
#ifdef CONFIG_X86_PAE
pmd_t gpmd;
#endif
/* First step: get the top-level Guest page table entry. */
gpgd = lgread(cpu, gpgd_addr(cpu, vaddr), pgd_t);
/* Toplevel not present? We can't map it in. */
......@@ -378,7 +537,14 @@ unsigned long guest_pa(struct lg_cpu *cpu, unsigned long vaddr)
return -1UL;
}
gpte = lgread(cpu, gpte_addr(gpgd, vaddr), pte_t);
#ifdef CONFIG_X86_PAE
gpmd = lgread(cpu, gpmd_addr(gpgd, vaddr), pmd_t);
if (!(pmd_flags(gpmd) & _PAGE_PRESENT))
kill_guest(cpu, "Bad address %#lx", vaddr);
gpte = lgread(cpu, gpte_addr(cpu, gpmd, vaddr), pte_t);
#else
gpte = lgread(cpu, gpte_addr(cpu, gpgd, vaddr), pte_t);
#endif
if (!(pte_flags(gpte) & _PAGE_PRESENT))
kill_guest(cpu, "Bad address %#lx", vaddr);
......@@ -405,6 +571,9 @@ static unsigned int new_pgdir(struct lg_cpu *cpu,
int *blank_pgdir)
{
unsigned int next;
#ifdef CONFIG_X86_PAE
pmd_t *pmd_table;
#endif
/* We pick one entry at random to throw out. Choosing the Least
* Recently Used might be better, but this is easy. */
......@@ -416,11 +585,28 @@ static unsigned int new_pgdir(struct lg_cpu *cpu,
/* If the allocation fails, just keep using the one we have */
if (!cpu->lg->pgdirs[next].pgdir)
next = cpu->cpu_pgd;
else
else {
#ifdef CONFIG_X86_PAE
/* In PAE mode, allocate a pmd page and populate the
* last pgd entry. */
pmd_table = (pmd_t *)get_zeroed_page(GFP_KERNEL);
if (!pmd_table) {
free_page((long)cpu->lg->pgdirs[next].pgdir);
set_pgd(cpu->lg->pgdirs[next].pgdir, __pgd(0));
next = cpu->cpu_pgd;
} else {
set_pgd(cpu->lg->pgdirs[next].pgdir +
SWITCHER_PGD_INDEX,
__pgd(__pa(pmd_table) | _PAGE_PRESENT));
/* This is a blank page, so there are no kernel
* mappings: caller must map the stack! */
*blank_pgdir = 1;
}
#else
*blank_pgdir = 1;
#endif
}
}
/* Record which Guest toplevel this shadows. */
cpu->lg->pgdirs[next].gpgdir = gpgdir;
/* Release all the non-kernel mappings. */
......@@ -431,7 +617,7 @@ static unsigned int new_pgdir(struct lg_cpu *cpu,
/*H:430 (iv) Switching page tables
*
* Now we've seen all the page table setting and manipulation, let's see what
* Now we've seen all the page table setting and manipulation, let's see
* what happens when the Guest changes page tables (ie. changes the top-level
* pgdir). This occurs on almost every context switch. */
void guest_new_pagetable(struct lg_cpu *cpu, unsigned long pgtable)
......@@ -460,10 +646,25 @@ static void release_all_pagetables(struct lguest *lg)
/* Every shadow pagetable this Guest has */
for (i = 0; i < ARRAY_SIZE(lg->pgdirs); i++)
if (lg->pgdirs[i].pgdir)
if (lg->pgdirs[i].pgdir) {
#ifdef CONFIG_X86_PAE
pgd_t *spgd;
pmd_t *pmdpage;
unsigned int k;
/* Get the last pmd page. */
spgd = lg->pgdirs[i].pgdir + SWITCHER_PGD_INDEX;
pmdpage = __va(pgd_pfn(*spgd) << PAGE_SHIFT);
/* And release the pmd entries of that pmd page,
* except for the switcher pmd. */
for (k = 0; k < SWITCHER_PMD_INDEX; k++)
release_pmd(&pmdpage[k]);
#endif
/* Every PGD entry except the Switcher at the top */
for (j = 0; j < SWITCHER_PGD_INDEX; j++)
release_pgd(lg, lg->pgdirs[i].pgdir + j);
release_pgd(lg->pgdirs[i].pgdir + j);
}
}
/* We also throw away everything when a Guest tells us it's changed a kernel
......@@ -504,24 +705,37 @@ static void do_set_pte(struct lg_cpu *cpu, int idx,
{
/* Look up the matching shadow page directory entry. */
pgd_t *spgd = spgd_addr(cpu, idx, vaddr);
#ifdef CONFIG_X86_PAE
pmd_t *spmd;
#endif
/* If the top level isn't present, there's no entry to update. */
if (pgd_flags(*spgd) & _PAGE_PRESENT) {
/* Otherwise, we start by releasing the existing entry. */
pte_t *spte = spte_addr(*spgd, vaddr);
#ifdef CONFIG_X86_PAE
spmd = spmd_addr(cpu, *spgd, vaddr);
if (pmd_flags(*spmd) & _PAGE_PRESENT) {
#endif
/* Otherwise, we start by releasing
* the existing entry. */
pte_t *spte = spte_addr(cpu, *spgd, vaddr);
release_pte(*spte);
/* If they're setting this entry as dirty or accessed, we might
* as well put that entry they've given us in now. This shaves
* 10% off a copy-on-write micro-benchmark. */
/* If they're setting this entry as dirty or accessed,
* we might as well put that entry they've given us
* in now. This shaves 10% off a
* copy-on-write micro-benchmark. */
if (pte_flags(gpte) & (_PAGE_DIRTY | _PAGE_ACCESSED)) {
check_gpte(cpu, gpte);
*spte = gpte_to_spte(cpu, gpte,
pte_flags(gpte) & _PAGE_DIRTY);
native_set_pte(spte,
gpte_to_spte(cpu, gpte,
pte_flags(gpte) & _PAGE_DIRTY));
} else
/* Otherwise kill it and we can demand_page() it in
* later. */
*spte = __pte(0);
/* Otherwise kill it and we can demand_page()
* it in later. */
native_set_pte(spte, __pte(0));
#ifdef CONFIG_X86_PAE
}
#endif
}
}
......@@ -568,12 +782,10 @@ void guest_set_pte(struct lg_cpu *cpu,
*
* So with that in mind here's our code to to update a (top-level) PGD entry:
*/
void guest_set_pmd(struct lguest *lg, unsigned long gpgdir, u32 idx)
void guest_set_pgd(struct lguest *lg, unsigned long gpgdir, u32 idx)
{
int pgdir;
/* The kernel seems to try to initialize this early on: we ignore its
* attempts to map over the Switcher. */
if (idx >= SWITCHER_PGD_INDEX)
return;
......@@ -581,8 +793,14 @@ void guest_set_pmd(struct lguest *lg, unsigned long gpgdir, u32 idx)
pgdir = find_pgdir(lg, gpgdir);
if (pgdir < ARRAY_SIZE(lg->pgdirs))
/* ... throw it away. */
release_pgd(lg, lg->pgdirs[pgdir].pgdir + idx);
release_pgd(lg->pgdirs[pgdir].pgdir + idx);
}
#ifdef CONFIG_X86_PAE
void guest_set_pmd(struct lguest *lg, unsigned long pmdp, u32 idx)
{
guest_pagetable_clear_all(&lg->cpus[0]);
}
#endif
/* Once we know how much memory we have we can construct simple identity
* (which set virtual == physical) and linear mappings
......@@ -596,8 +814,16 @@ static unsigned long setup_pagetables(struct lguest *lg,
{
pgd_t __user *pgdir;
pte_t __user *linear;
unsigned int mapped_pages, i, linear_pages, phys_linear;
unsigned long mem_base = (unsigned long)lg->mem_base;
unsigned int mapped_pages, i, linear_pages;
#ifdef CONFIG_X86_PAE
pmd_t __user *pmds;
unsigned int j;
pgd_t pgd;
pmd_t pmd;
#else
unsigned int phys_linear;
#endif
/* We have mapped_pages frames to map, so we need
* linear_pages page tables to map them. */
......@@ -610,6 +836,9 @@ static unsigned long setup_pagetables(struct lguest *lg,
/* Now we use the next linear_pages pages as pte pages */
linear = (void *)pgdir - linear_pages * PAGE_SIZE;
#ifdef CONFIG_X86_PAE
pmds = (void *)linear - PAGE_SIZE;
#endif
/* Linear mapping is easy: put every page's address into the
* mapping in order. */
for (i = 0; i < mapped_pages; i++) {
......@@ -621,6 +850,22 @@ static unsigned long setup_pagetables(struct lguest *lg,
/* The top level points to the linear page table pages above.
* We setup the identity and linear mappings here. */
#ifdef CONFIG_X86_PAE
for (i = j = 0; i < mapped_pages && j < PTRS_PER_PMD;
i += PTRS_PER_PTE, j++) {
native_set_pmd(&pmd, __pmd(((unsigned long)(linear + i)
- mem_base) | _PAGE_PRESENT | _PAGE_RW | _PAGE_USER));
if (copy_to_user(&pmds[j], &pmd, sizeof(pmd)) != 0)
return -EFAULT;
}
set_pgd(&pgd, __pgd(((u32)pmds - mem_base) | _PAGE_PRESENT));
if (copy_to_user(&pgdir[0], &pgd, sizeof(pgd)) != 0)
return -EFAULT;
if (copy_to_user(&pgdir[3], &pgd, sizeof(pgd)) != 0)
return -EFAULT;
#else
phys_linear = (unsigned long)linear - mem_base;
for (i = 0; i < mapped_pages; i += PTRS_PER_PTE) {
pgd_t pgd;
......@@ -633,6 +878,7 @@ static unsigned long setup_pagetables(struct lguest *lg,
&pgd, sizeof(pgd)))
return -EFAULT;
}
#endif
/* We return the top level (guest-physical) address: remember where
* this is. */
......@@ -648,7 +894,10 @@ int init_guest_pagetable(struct lguest *lg)
u64 mem;
u32 initrd_size;
struct boot_params __user *boot = (struct boot_params *)lg->mem_base;
#ifdef CONFIG_X86_PAE
pgd_t *pgd;
pmd_t *pmd_table;
#endif
/* Get the Guest memory size and the ramdisk size from the boot header
* located at lg->mem_base (Guest address 0). */
if (copy_from_user(&mem, &boot->e820_map[0].size, sizeof(mem))
......@@ -663,6 +912,15 @@ int init_guest_pagetable(struct lguest *lg)
lg->pgdirs[0].pgdir = (pgd_t *)get_zeroed_page(GFP_KERNEL);
if (!lg->pgdirs[0].pgdir)
return -ENOMEM;
#ifdef CONFIG_X86_PAE
pgd = lg->pgdirs[0].pgdir;
pmd_table = (pmd_t *) get_zeroed_page(GFP_KERNEL);
if (!pmd_table)
return -ENOMEM;
set_pgd(pgd + SWITCHER_PGD_INDEX,
__pgd(__pa(pmd_table) | _PAGE_PRESENT));
#endif
lg->cpus[0].cpu_pgd = 0;
return 0;
}
......@@ -673,16 +931,23 @@ void page_table_guest_data_init(struct lg_cpu *cpu)
/* We get the kernel address: above this is all kernel memory. */
if (get_user(cpu->lg->kernel_address,
&cpu->lg->lguest_data->kernel_address)
/* We tell the Guest that it can't use the top 4MB of virtual
* addresses used by the Switcher. */
|| put_user(4U*1024*1024, &cpu->lg->lguest_data->reserve_mem)
|| put_user(cpu->lg->pgdirs[0].gpgdir, &cpu->lg->lguest_data->pgdir))
/* We tell the Guest that it can't use the top 2 or 4 MB
* of virtual addresses used by the Switcher. */
|| put_user(RESERVE_MEM * 1024 * 1024,
&cpu->lg->lguest_data->reserve_mem)
|| put_user(cpu->lg->pgdirs[0].gpgdir,
&cpu->lg->lguest_data->pgdir))
kill_guest(cpu, "bad guest page %p", cpu->lg->lguest_data);
/* In flush_user_mappings() we loop from 0 to
* "pgd_index(lg->kernel_address)". This assumes it won't hit the
* Switcher mappings, so check that now. */
#ifdef CONFIG_X86_PAE
if (pgd_index(cpu->lg->kernel_address) == SWITCHER_PGD_INDEX &&
pmd_index(cpu->lg->kernel_address) == SWITCHER_PMD_INDEX)
#else
if (pgd_index(cpu->lg->kernel_address) >= SWITCHER_PGD_INDEX)
#endif
kill_guest(cpu, "bad kernel address %#lx",
cpu->lg->kernel_address);
}
......@@ -708,16 +973,30 @@ void free_guest_pagetable(struct lguest *lg)
void map_switcher_in_guest(struct lg_cpu *cpu, struct lguest_pages *pages)
{
pte_t *switcher_pte_page = __get_cpu_var(switcher_pte_pages);
pgd_t switcher_pgd;
pte_t regs_pte;
unsigned long pfn;
#ifdef CONFIG_X86_PAE
pmd_t switcher_pmd;
pmd_t *pmd_table;
native_set_pmd(&switcher_pmd, pfn_pmd(__pa(switcher_pte_page) >>
PAGE_SHIFT, PAGE_KERNEL_EXEC));
pmd_table = __va(pgd_pfn(cpu->lg->
pgdirs[cpu->cpu_pgd].pgdir[SWITCHER_PGD_INDEX])
<< PAGE_SHIFT);
native_set_pmd(&pmd_table[SWITCHER_PMD_INDEX], switcher_pmd);
#else
pgd_t switcher_pgd;
/* Make the last PGD entry for this Guest point to the Switcher's PTE
* page for this CPU (with appropriate flags). */
switcher_pgd = __pgd(__pa(switcher_pte_page) | __PAGE_KERNEL);
switcher_pgd = __pgd(__pa(switcher_pte_page) | __PAGE_KERNEL_EXEC);
cpu->lg->pgdirs[cpu->cpu_pgd].pgdir[SWITCHER_PGD_INDEX] = switcher_pgd;
#endif
/* We also change the Switcher PTE page. When we're running the Guest,
* we want the Guest's "regs" page to appear where the first Switcher
* page for this CPU is. This is an optimization: when the Switcher
......@@ -726,8 +1005,9 @@ void map_switcher_in_guest(struct lg_cpu *cpu, struct lguest_pages *pages)
* page is already mapped there, we don't have to copy them out
* again. */
pfn = __pa(cpu->regs_page) >> PAGE_SHIFT;
regs_pte = pfn_pte(pfn, __pgprot(__PAGE_KERNEL));
switcher_pte_page[(unsigned long)pages/PAGE_SIZE%PTRS_PER_PTE] = regs_pte;
native_set_pte(&regs_pte, pfn_pte(pfn, PAGE_KERNEL));
native_set_pte(&switcher_pte_page[pte_index((unsigned long)pages)],
regs_pte);
}
/*:*/
......@@ -752,21 +1032,21 @@ static __init void populate_switcher_pte_page(unsigned int cpu,
/* The first entries are easy: they map the Switcher code. */
for (i = 0; i < pages; i++) {
pte[i] = mk_pte(switcher_page[i],
__pgprot(_PAGE_PRESENT|_PAGE_ACCESSED));
native_set_pte(&pte[i], mk_pte(switcher_page[i],
__pgprot(_PAGE_PRESENT|_PAGE_ACCESSED)));
}
/* The only other thing we map is this CPU's pair of pages. */
i = pages + cpu*2;
/* First page (Guest registers) is writable from the Guest */
pte[i] = pfn_pte(page_to_pfn(switcher_page[i]),
__pgprot(_PAGE_PRESENT|_PAGE_ACCESSED|_PAGE_RW));
native_set_pte(&pte[i], pfn_pte(page_to_pfn(switcher_page[i]),
__pgprot(_PAGE_PRESENT|_PAGE_ACCESSED|_PAGE_RW)));
/* The second page contains the "struct lguest_ro_state", and is
* read-only. */
pte[i+1] = pfn_pte(page_to_pfn(switcher_page[i+1]),
__pgprot(_PAGE_PRESENT|_PAGE_ACCESSED));
native_set_pte(&pte[i+1], pfn_pte(page_to_pfn(switcher_page[i+1]),
__pgprot(_PAGE_PRESENT|_PAGE_ACCESSED)));
}
/* We've made it through the page table code. Perhaps our tired brains are
......
drivers/lguest/segments.c
View file @ 7f3591cf
......@@ -150,7 +150,7 @@ void load_guest_gdt_entry(struct lg_cpu *cpu, u32 num, u32 lo, u32 hi)
{
/* We assume the Guest has the same number of GDT entries as the
* Host, otherwise we'd have to dynamically allocate the Guest GDT. */
if (num > ARRAY_SIZE(cpu->arch.gdt))
if (num >= ARRAY_SIZE(cpu->arch.gdt))
kill_guest(cpu, "too many gdt entries %i", num);
/* Set it up, then fix it. */
......
fs/eventfd.c
View file @ 7f3591cf
......@@ -16,6 +16,7 @@
#include <linux/anon_inodes.h>
#include <linux/eventfd.h>
#include <linux/syscalls.h>
#include <linux/module.h>
struct eventfd_ctx {
wait_queue_head_t wqh;
......@@ -56,6 +57,7 @@ int eventfd_signal(struct file *file, int n)
return n;
}
EXPORT_SYMBOL_GPL(eventfd_signal);
static int eventfd_release(struct inode *inode, struct file *file)
{
......@@ -197,6 +199,7 @@ struct file *eventfd_fget(int fd)
return file;
}
EXPORT_SYMBOL_GPL(eventfd_fget);
SYSCALL_DEFINE2(eventfd2, unsigned int, count, int, flags)
{
......
include/linux/lguest.h
View file @ 7f3591cf
......@@ -30,6 +30,10 @@ struct lguest_data
/* Wallclock time set by the Host. */
struct timespec time;
/* Interrupt pending set by the Host. The Guest should do a hypercall
* if it re-enables interrupts and sees this set (to X86_EFLAGS_IF). */
int irq_pending;
/* Async hypercall ring. Instead of directly making hypercalls, we can
* place them in here for processing the next time the Host wants.
* This batching can be quite efficient. */
......
include/linux/lguest_launcher.h
View file @ 7f3591cf
......@@ -57,7 +57,8 @@ enum lguest_req
LHREQ_INITIALIZE, /* + base, pfnlimit, start */
LHREQ_GETDMA, /* No longer used */
LHREQ_IRQ, /* + irq */
LHREQ_BREAK, /* + on/off flag (on blocks until someone does off) */
LHREQ_BREAK, /* No longer used */
LHREQ_EVENTFD, /* + address, fd. */
};
/* The alignment to use between consumer and producer parts of vring.
......
kernel/sched.c
View file @ 7f3591cf
......@@ -2192,6 +2192,7 @@ void kick_process(struct task_struct *p)
smp_send_reschedule(cpu);
preempt_enable();
}
EXPORT_SYMBOL_GPL(kick_process);
/*
* Return a low guess at the load of a migration-source cpu weighted
......
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