Merge tag 'uml-for-linus-6.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux

Pull UML updates from Richard Weinberger:

 - Removal of dead code (TT mode leftovers, etc)

 - Fixes for the network vector driver

 - Fixes for time-travel mode

* tag 'uml-for-linus-6.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux:
  um: fix time-travel syscall scheduling hack
  um: Remove outdated asm/sysrq.h header
  um: Remove the declaration of user_thread function
  um: Remove the call to SUBARCH_EXECVE1 macro
  um: Remove unused mm_fd field from mm_id
  um: Remove unused fields from thread_struct
  um: Remove the redundant newpage check in update_pte_range
  um: Remove unused kpte_clear_flush macro
  um: Remove obsoleted declaration for execute_syscall_skas
  user_mode_linux_howto_v2: add VDE vector support in doc
  vector_user: add VDE support
  um: remove ARCH_NO_PREEMPT_DYNAMIC
  um: vector: Fix NAPI budget handling
  um: vector: Replace locks guarding queue depth with atomics
  um: remove variable stack array in os_rcv_fd_msg()

Documentation/virt/uml/user_mode_linux_howto_v2.rst

@@ -217,6 +217,8 @@ remote UML and other VM instances.
 +-----------+--------+------------------------------------+------------+
 | fd        | vector | dependent on fd type               | varies     |
 +-----------+--------+------------------------------------+------------+
+| vde       | vector | dep. on VDE VPN: Virt.Net Locator  | varies     |
++-----------+--------+------------------------------------+------------+
 | tuntap    | legacy | none                               | ~ 500Mbit  |
 +-----------+--------+------------------------------------+------------+
 | daemon    | legacy | none                               | ~ 450Mbit  |
@@ -573,6 +575,41 @@ https://github.com/NetSys/bess/wiki/Built-In-Modules-and-Ports
 
 BESS transport does not require any special privileges.
 
+VDE vector transport
+--------------------
+
+Virtual Distributed Ethernet (VDE) is a project whose main goal is to provide a
+highly flexible support for virtual networking.
+
+http://wiki.virtualsquare.org/#/tutorials/vdebasics
+
+Common usages of VDE include fast prototyping and teaching.
+
+Examples:
+
+   ``vecX:transport=vde,vnl=tap://tap0``
+
+use tap0
+
+   ``vecX:transport=vde,vnl=slirp://``
+
+use slirp
+
+   ``vec0:transport=vde,vnl=vde:///tmp/switch``
+
+connect to a vde switch
+
+   ``vecX:transport=\"vde,vnl=cmd://ssh remote.host //tmp/sshlirp\"``
+
+connect to a remote slirp (instant VPN: convert ssh to VPN, it uses sshlirp)
+https://github.com/virtualsquare/sshlirp
+
+   ``vec0:transport=vde,vnl=vxvde://234.0.0.1``
+
+connect to a local area cloud (all the UML nodes using the same
+multicast address running on hosts in the same multicast domain (LAN)
+will be automagically connected together to a virtual LAN.
+
 Configuring Legacy transports
 =============================
 

arch/um/Kconfig

@@ -11,7 +11,6 @@ config UML
 	select ARCH_HAS_KCOV
 	select ARCH_HAS_STRNCPY_FROM_USER
 	select ARCH_HAS_STRNLEN_USER
-	select ARCH_NO_PREEMPT_DYNAMIC
 	select HAVE_ARCH_AUDITSYSCALL
 	select HAVE_ARCH_KASAN if X86_64
 	select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN

arch/um/drivers/vector_kern.h

@@ -14,6 +14,7 @@
 #include <linux/ctype.h>
 #include <linux/workqueue.h>
 #include <linux/interrupt.h>
+#include <asm/atomic.h>
 
 #include "vector_user.h"
 
@@ -44,7 +45,8 @@ struct vector_queue {
 	struct net_device *dev;
 	spinlock_t head_lock;
 	spinlock_t tail_lock;
-	int queue_depth, head, tail, max_depth, max_iov_frags;
+	atomic_t queue_depth;
+	int head, tail, max_depth, max_iov_frags;
 	short options;
 };
 

arch/um/drivers/vector_user.c

@@ -46,6 +46,9 @@
 #define TRANS_FD "fd"
 #define TRANS_FD_LEN strlen(TRANS_FD)
 
+#define TRANS_VDE "vde"
+#define TRANS_VDE_LEN strlen(TRANS_VDE)
+
 #define VNET_HDR_FAIL "could not enable vnet headers on fd %d"
 #define TUN_GET_F_FAIL "tapraw: TUNGETFEATURES failed: %s"
 #define L2TPV3_BIND_FAIL "l2tpv3_open : could not bind socket err=%i"
@@ -434,6 +437,84 @@ static struct vector_fds *user_init_fd_fds(struct arglist *ifspec)
 	return NULL;
 }
 
+/* enough char to store an int type */
+#define ENOUGH(type) ((CHAR_BIT * sizeof(type) - 1) / 3 + 2)
+#define ENOUGH_OCTAL(type) ((CHAR_BIT * sizeof(type) + 2) / 3)
+/* vde_plug --descr xx --port2 xx --mod2 xx --group2 xx seqpacket://NN vnl (NULL) */
+#define VDE_MAX_ARGC 12
+#define VDE_SEQPACKET_HEAD "seqpacket://"
+#define VDE_SEQPACKET_HEAD_LEN (sizeof(VDE_SEQPACKET_HEAD) - 1)
+#define VDE_DEFAULT_DESCRIPTION "UML"
+
+static struct vector_fds *user_init_vde_fds(struct arglist *ifspec)
+{
+	char seqpacketvnl[VDE_SEQPACKET_HEAD_LEN + ENOUGH(int) + 1];
+	char *argv[VDE_MAX_ARGC] = {"vde_plug"};
+	int argc = 1;
+	int rv;
+	int sv[2];
+	struct vector_fds *result = NULL;
+
+	char *vnl = uml_vector_fetch_arg(ifspec,"vnl");
+	char *descr = uml_vector_fetch_arg(ifspec,"descr");
+	char *port = uml_vector_fetch_arg(ifspec,"port");
+	char *mode = uml_vector_fetch_arg(ifspec,"mode");
+	char *group = uml_vector_fetch_arg(ifspec,"group");
+	if (descr == NULL) descr = VDE_DEFAULT_DESCRIPTION;
+
+	argv[argc++] = "--descr";
+	argv[argc++] = descr;
+	if (port != NULL) {
+		argv[argc++] = "--port2";
+		argv[argc++] = port;
+	}
+	if (mode != NULL) {
+		argv[argc++] = "--mod2";
+		argv[argc++] = mode;
+	}
+	if (group != NULL) {
+		argv[argc++] = "--group2";
+		argv[argc++] = group;
+	}
+	argv[argc++] = seqpacketvnl;
+	argv[argc++] = vnl;
+	argv[argc++] = NULL;
+
+	rv = socketpair(AF_UNIX, SOCK_SEQPACKET, 0, sv);
+	if (rv  < 0) {
+		printk(UM_KERN_ERR "vde: seqpacket socketpair err %d", -errno);
+		return NULL;
+	}
+	rv = os_set_exec_close(sv[0]);
+	if (rv  < 0) {
+		printk(UM_KERN_ERR "vde: seqpacket socketpair cloexec err %d", -errno);
+		goto vde_cleanup_sv;
+	}
+	snprintf(seqpacketvnl, sizeof(seqpacketvnl), VDE_SEQPACKET_HEAD "%d", sv[1]);
+
+	run_helper(NULL, NULL, argv);
+
+	close(sv[1]);
+
+	result = uml_kmalloc(sizeof(struct vector_fds), UM_GFP_KERNEL);
+	if (result == NULL) {
+		printk(UM_KERN_ERR "fd open: allocation failed");
+		goto vde_cleanup;
+	}
+
+	result->rx_fd = sv[0];
+	result->tx_fd = sv[0];
+	result->remote_addr_size = 0;
+	result->remote_addr = NULL;
+	return result;
+
+vde_cleanup_sv:
+	close(sv[1]);
+vde_cleanup:
+	close(sv[0]);
+	return NULL;
+}
+
 static struct vector_fds *user_init_raw_fds(struct arglist *ifspec)
 {
 	int rxfd = -1, txfd = -1;
@@ -673,6 +754,8 @@ struct vector_fds *uml_vector_user_open(
 		return user_init_unix_fds(parsed, ID_BESS);
 	if (strncmp(transport, TRANS_FD, TRANS_FD_LEN) == 0)
 		return user_init_fd_fds(parsed);
+	if (strncmp(transport, TRANS_VDE, TRANS_VDE_LEN) == 0)
+		return user_init_vde_fds(parsed);
 	return NULL;
 }
 

arch/um/include/asm/pgtable.h

@@ -359,11 +359,4 @@ static inline pte_t pte_swp_clear_exclusive(pte_t pte)
 	return pte;
 }
 
-/* Clear a kernel PTE and flush it from the TLB */
-#define kpte_clear_flush(ptep, vaddr)		\
-do {						\
-	pte_clear(&init_mm, (vaddr), (ptep));	\
-	__flush_tlb_one((vaddr));		\
-} while (0)
-
 #endif

arch/um/include/asm/processor-generic.h

@@ -28,20 +28,10 @@ struct thread_struct {
 	struct arch_thread arch;
 	jmp_buf switch_buf;
 	struct {
-		int op;
-		union {
-			struct {
-				int pid;
-			} fork, exec;
-			struct {
-				int (*proc)(void *);
-				void *arg;
-			} thread;
-			struct {
-				void (*proc)(void *);
-				void *arg;
-			} cb;
-		} u;
+		struct {
+			int (*proc)(void *);
+			void *arg;
+		} thread;
 	} request;
 };
 
@@ -51,7 +41,7 @@ struct thread_struct {
 	.fault_addr		= NULL, \
 	.prev_sched		= NULL, \
 	.arch			= INIT_ARCH_THREAD, \
-	.request		= { 0 } \
+	.request		= { } \
 }
 
 /*

arch/um/include/asm/sysrq.h

-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef __UM_SYSRQ_H
-#define __UM_SYSRQ_H
-
-struct task_struct;
-extern void show_trace(struct task_struct* task, unsigned long *stack);
-
-#endif

arch/um/include/shared/skas/mm_id.h

@@ -7,10 +7,7 @@
 #define __MM_ID_H
 
 struct mm_id {
-	union {
-		int mm_fd;
-		int pid;
-	} u;
+	int pid;
 	unsigned long stack;
 	int syscall_data_len;
 };

arch/um/include/shared/skas/skas.h

@@ -10,10 +10,8 @@
 
 extern int userspace_pid[];
 
-extern int user_thread(unsigned long stack, int flags);
 extern void new_thread_handler(void);
 extern void handle_syscall(struct uml_pt_regs *regs);
-extern long execute_syscall_skas(void *r);
 extern unsigned long current_stub_stack(void);
 extern struct mm_id *current_mm_id(void);
 extern void current_mm_sync(void);

arch/um/kernel/exec.c

@@ -35,8 +35,5 @@ void start_thread(struct pt_regs *regs, unsigned long eip, unsigned long esp)
 	PT_REGS_IP(regs) = eip;
 	PT_REGS_SP(regs) = esp;
 	clear_thread_flag(TIF_SINGLESTEP);
-#ifdef SUBARCH_EXECVE1
-	SUBARCH_EXECVE1(regs->regs);
-#endif
 }
 EXPORT_SYMBOL(start_thread);

arch/um/kernel/process.c

@@ -109,8 +109,8 @@ void new_thread_handler(void)
 		schedule_tail(current->thread.prev_sched);
 	current->thread.prev_sched = NULL;
 
-	fn = current->thread.request.u.thread.proc;
-	arg = current->thread.request.u.thread.arg;
+	fn = current->thread.request.thread.proc;
+	arg = current->thread.request.thread.arg;
 
 	/*
 	 * callback returns only if the kernel thread execs a process
@@ -158,8 +158,8 @@ int copy_thread(struct task_struct * p, const struct kernel_clone_args *args)
 		arch_copy_thread(&current->thread.arch, &p->thread.arch);
 	} else {
 		get_safe_registers(p->thread.regs.regs.gp, p->thread.regs.regs.fp);
-		p->thread.request.u.thread.proc = args->fn;
-		p->thread.request.u.thread.arg = args->fn_arg;
+		p->thread.request.thread.proc = args->fn;
+		p->thread.request.thread.arg = args->fn_arg;
 		handler = new_thread_handler;
 	}
 

arch/um/kernel/reboot.c

@@ -29,7 +29,7 @@ static void kill_off_processes(void)
 		t = find_lock_task_mm(p);
 		if (!t)
 			continue;
-		pid = t->mm->context.id.u.pid;
+		pid = t->mm->context.id.pid;
 		task_unlock(t);
 		os_kill_ptraced_process(pid, 1);
 	}

arch/um/kernel/skas/mmu.c

@@ -32,11 +32,11 @@ int init_new_context(struct task_struct *task, struct mm_struct *mm)
 	new_id->stack = stack;
 
 	block_signals_trace();
-	new_id->u.pid = start_userspace(stack);
+	new_id->pid = start_userspace(stack);
 	unblock_signals_trace();
 
-	if (new_id->u.pid < 0) {
-		ret = new_id->u.pid;
+	if (new_id->pid < 0) {
+		ret = new_id->pid;
 		goto out_free;
 	}
 
@@ -83,12 +83,12 @@ void destroy_context(struct mm_struct *mm)
 	 * whole UML suddenly dying.  Also, cover negative and
 	 * 1 cases, since they shouldn't happen either.
 	 */
-	if (mmu->id.u.pid < 2) {
+	if (mmu->id.pid < 2) {
 		printk(KERN_ERR "corrupt mm_context - pid = %d\n",
-		       mmu->id.u.pid);
+		       mmu->id.pid);
 		return;
 	}
-	os_kill_ptraced_process(mmu->id.u.pid, 1);
+	os_kill_ptraced_process(mmu->id.pid, 1);
 
 	free_pages(mmu->id.stack, ilog2(STUB_DATA_PAGES));
 }

arch/um/kernel/skas/process.c

@@ -39,8 +39,8 @@ int __init start_uml(void)
 
 	init_new_thread_signals();
 
-	init_task.thread.request.u.thread.proc = start_kernel_proc;
-	init_task.thread.request.u.thread.arg = NULL;
+	init_task.thread.request.thread.proc = start_kernel_proc;
+	init_task.thread.request.thread.arg = NULL;
 	return start_idle_thread(task_stack_page(&init_task),
 				 &init_task.thread.switch_buf);
 }

arch/um/kernel/skas/syscall.c

@@ -12,23 +12,13 @@
 #include <sysdep/syscalls.h>
 #include <linux/time-internal.h>
 #include <asm/unistd.h>
+#include <asm/delay.h>
 
 void handle_syscall(struct uml_pt_regs *r)
 {
 	struct pt_regs *regs = container_of(r, struct pt_regs, regs);
 	int syscall;
 
-	/*
-	 * If we have infinite CPU resources, then make every syscall also a
-	 * preemption point, since we don't have any other preemption in this
-	 * case, and kernel threads would basically never run until userspace
-	 * went to sleep, even if said userspace interacts with the kernel in
-	 * various ways.
-	 */
-	if (time_travel_mode == TT_MODE_INFCPU ||
-	    time_travel_mode == TT_MODE_EXTERNAL)
-		schedule();
-
 	/* Initialize the syscall number and default return value. */
 	UPT_SYSCALL_NR(r) = PT_SYSCALL_NR(r->gp);
 	PT_REGS_SET_SYSCALL_RETURN(regs, -ENOSYS);
@@ -41,9 +31,25 @@ void handle_syscall(struct uml_pt_regs *r)
 		goto out;
 
 	syscall = UPT_SYSCALL_NR(r);
-	if (syscall >= 0 && syscall < __NR_syscalls)
-		PT_REGS_SET_SYSCALL_RETURN(regs,
-				EXECUTE_SYSCALL(syscall, regs));
+	if (syscall >= 0 && syscall < __NR_syscalls) {
+		unsigned long ret = EXECUTE_SYSCALL(syscall, regs);
+
+		PT_REGS_SET_SYSCALL_RETURN(regs, ret);
+
+		/*
+		 * An error value here can be some form of -ERESTARTSYS
+		 * and then we'd just loop. Make any error syscalls take
+		 * some time, so that it won't just loop if something is
+		 * not ready, and hopefully other things will make some
+		 * progress.
+		 */
+		if (IS_ERR_VALUE(ret) &&
+		    (time_travel_mode == TT_MODE_INFCPU ||
+		     time_travel_mode == TT_MODE_EXTERNAL)) {
+			um_udelay(1);
+			schedule();
+		}
+	}
 
 out:
 	syscall_trace_leave(regs);

arch/um/kernel/sysrq.c

@@ -11,7 +11,6 @@
 #include <linux/sched/debug.h>
 #include <linux/sched/task_stack.h>
 
-#include <asm/sysrq.h>
 #include <asm/stacktrace.h>
 #include <os.h>
 

arch/um/kernel/time.c

@@ -839,7 +839,7 @@ static irqreturn_t um_timer(int irq, void *dev)
 	if (get_current()->mm != NULL)
 	{
         /* userspace - relay signal, results in correct userspace timers */
-		os_alarm_process(get_current()->mm->context.id.u.pid);
+		os_alarm_process(get_current()->mm->context.id.pid);
 	}
 
 	(*timer_clockevent.event_handler)(&timer_clockevent);

arch/um/kernel/tlb.c

@@ -82,16 +82,12 @@ static inline int update_pte_range(pmd_t *pmd, unsigned long addr,
 			(x ? UM_PROT_EXEC : 0));
 		if (pte_newpage(*pte)) {
 			if (pte_present(*pte)) {
-				if (pte_newpage(*pte)) {
-					__u64 offset;
-					unsigned long phys =
-						pte_val(*pte) & PAGE_MASK;
-					int fd =  phys_mapping(phys, &offset);
-
-					ret = ops->mmap(ops->mm_idp, addr,
-							PAGE_SIZE, prot, fd,
-							offset);
-				}
+				__u64 offset;
+				unsigned long phys = pte_val(*pte) & PAGE_MASK;
+				int fd = phys_mapping(phys, &offset);
+
+				ret = ops->mmap(ops->mm_idp, addr, PAGE_SIZE,
+						prot, fd, offset);
 			} else
 				ret = ops->unmap(ops->mm_idp, addr, PAGE_SIZE);
 		} else if (pte_newprot(*pte))

arch/um/os-Linux/file.c

@@ -528,7 +528,8 @@ int os_shutdown_socket(int fd, int r, int w)
 ssize_t os_rcv_fd_msg(int fd, int *fds, unsigned int n_fds,
 		      void *data, size_t data_len)
 {
-	char buf[CMSG_SPACE(sizeof(*fds) * n_fds)];
+#define MAX_RCV_FDS	2
+	char buf[CMSG_SPACE(sizeof(*fds) * MAX_RCV_FDS)];
 	struct cmsghdr *cmsg;
 	struct iovec iov = {
 		.iov_base = data,
@@ -538,10 +539,13 @@ ssize_t os_rcv_fd_msg(int fd, int *fds, unsigned int n_fds,
 		.msg_iov = &iov,
 		.msg_iovlen = 1,
 		.msg_control = buf,
-		.msg_controllen = sizeof(buf),
+		.msg_controllen = CMSG_SPACE(sizeof(*fds) * n_fds),
 	};
 	int n;
 
+	if (n_fds > MAX_RCV_FDS)
+		return -EINVAL;
+
 	n = recvmsg(fd, &msg, 0);
 	if (n < 0)
 		return -errno;

arch/um/os-Linux/skas/mem.c

@@ -78,7 +78,7 @@ static inline long do_syscall_stub(struct mm_id *mm_idp)
 {
 	struct stub_data *proc_data = (void *)mm_idp->stack;
 	int n, i;
-	int err, pid = mm_idp->u.pid;
+	int err, pid = mm_idp->pid;
 
 	n = ptrace_setregs(pid, syscall_regs);
 	if (n < 0) {

arch/um/os-Linux/skas/process.c

@@ -588,5 +588,5 @@ void reboot_skas(void)
 
 void __switch_mm(struct mm_id *mm_idp)
 {
-	userspace_pid[0] = mm_idp->u.pid;
+	userspace_pid[0] = mm_idp->pid;
 }

arch/x86/um/sysrq_32.c

@@ -9,7 +9,6 @@
 #include <linux/sched/debug.h>
 #include <linux/kallsyms.h>
 #include <asm/ptrace.h>
-#include <asm/sysrq.h>
 
 /* This is declared by <linux/sched.h> */
 void show_regs(struct pt_regs *regs)

arch/x86/um/sysrq_64.c

@@ -12,7 +12,6 @@
 #include <linux/utsname.h>
 #include <asm/current.h>
 #include <asm/ptrace.h>
-#include <asm/sysrq.h>
 
 void show_regs(struct pt_regs *regs)
 {