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  1. 24 Aug, 2017 1 commit
    • Juergen Gross's avatar
      x86/paravirt/xen: Remove xen_patch() · edcb5cf8
      Juergen Gross authored 
      Xen's paravirt patch function xen_patch() does some special casing for
irq_ops functions to apply relocations when those functions can be
patched inline instead of calls.

Unfortunately none of the special case function replacements is small
enough to be patched inline, so the special case never applies.

As xen_patch() will call paravirt_patch_default() in all cases it can
be just dropped. xen-asm.h doesn't seem necessary without xen_patch()
as the only thing left in it would be the definition of XEN_EFLAGS_NMI
used only once. So move that definition and remove xen-asm.h.
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Reviewed-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: boris.ostrovsky@oracle.com
Cc: lguest@lists.ozlabs.org
Cc: rusty@rustcorp.com.au
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/20170816173157.8633-2-jgross@suse.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      edcb5cf8
  3. 13 Jun, 2017 2 commits
    • Ankur Arora's avatar
      xen/vcpu: Handle xen_vcpu_setup() failure in hotplug · c9b5d98b
      Ankur Arora authored 
      The hypercall VCPUOP_register_vcpu_info can fail. This failure is
handled by making per_cpu(xen_vcpu, cpu) point to its shared_info
slot and those without one (cpu >= MAX_VIRT_CPUS) be NULL.

For PVH/PVHVM, this is not enough, because we also need to pull
these VCPUs out of circulation.

Fix for PVH/PVHVM: on registration failure in the cpuhp prepare
callback (xen_cpu_up_prepare_hvm()), return an error to the cpuhp
state-machine so it can fail the CPU init.

Fix for PV: the registration happens before smp_init(), so, in the
failure case we clamp setup_max_cpus and limit the number of VCPUs
that smp_init() will bring-up to MAX_VIRT_CPUS.
This is functionally correct but it makes the code a bit simpler
if we get rid of this explicit clamping: for VCPUs that don't have
valid xen_vcpu, fail the CPU init in the cpuhp prepare callback
(xen_cpu_up_prepare_pv()).
Reviewed-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: default avatarAnkur Arora <ankur.a.arora@oracle.com>
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
      c9b5d98b
    • Ankur Arora's avatar
      xen/vcpu: Simplify xen_vcpu related code · ad73fd59
      Ankur Arora authored 
      Largely mechanical changes to aid unification of xen_vcpu_restore()
logic for PV, PVH and PVHVM.

xen_vcpu_setup(): the only change in logic is that clamp_max_cpus()
is now handled inside the "if (!xen_have_vcpu_info_placement)" block.

xen_vcpu_restore(): code movement from enlighten_pv.c to enlighten.c.

xen_vcpu_info_reset(): pulls together all the code where xen_vcpu
is set to default.
Reviewed-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: default avatarAnkur Arora <ankur.a.arora@oracle.com>
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
      ad73fd59
  5. 02 May, 2017 4 commits
  7. 07 Feb, 2017 1 commit
  9. 25 Dec, 2016 1 commit
  11. 25 Jul, 2016 1 commit
  13. 23 Nov, 2015 1 commit
  15. 20 Aug, 2015 5 commits
  17. 10 Aug, 2015 1 commit
    • Jason A. Donenfeld's avatar
      x86/xen: build "Xen PV" APIC driver for domU as well · fc5fee86
      Jason A. Donenfeld authored 
      It turns out that a PV domU also requires the "Xen PV" APIC
driver. Otherwise, the flat driver is used and we get stuck in busy
loops that never exit, such as in this stack trace:

(gdb) target remote localhost:9999
Remote debugging using localhost:9999
__xapic_wait_icr_idle () at ./arch/x86/include/asm/ipi.h:56
56              while (native_apic_mem_read(APIC_ICR) & APIC_ICR_BUSY)
(gdb) bt
 #0  __xapic_wait_icr_idle () at ./arch/x86/include/asm/ipi.h:56
 #1  __default_send_IPI_shortcut (shortcut=<optimized out>,
dest=<optimized out>, vector=<optimized out>) at
./arch/x86/include/asm/ipi.h:75
 #2  apic_send_IPI_self (vector=246) at arch/x86/kernel/apic/probe_64.c:54
 #3  0xffffffff81011336 in arch_irq_work_raise () at
arch/x86/kernel/irq_work.c:47
 #4  0xffffffff8114990c in irq_work_queue (work=0xffff88000fc0e400) at
kernel/irq_work.c:100
 #5  0xffffffff8110c29d in wake_up_klogd () at kernel/printk/printk.c:2633
 #6  0xffffffff8110ca60 in vprintk_emit (facility=0, level=<optimized
out>, dict=0x0 <irq_stack_union>, dictlen=<optimized out>,
fmt=<optimized out>, args=<optimized out>)
    at kernel/printk/printk.c:1778
 #7  0xffffffff816010c8 in printk (fmt=<optimized out>) at
kernel/printk/printk.c:1868
 #8  0xffffffffc00013ea in ?? ()
 #9  0x0000000000000000 in ?? ()

Mailing-list-thread: https://lkml.org/lkml/2015/8/4/755Signed-off-by: default avatarJason A. Donenfeld <Jason@zx2c4.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
      fc5fee86
  19. 22 Apr, 2015 1 commit
  21. 28 Jan, 2015 1 commit
  23. 04 Dec, 2014 3 commits
    • Juergen Gross's avatar
      xen: switch to linear virtual mapped sparse p2m list · 054954eb
      Juergen Gross authored 
      At start of the day the Xen hypervisor presents a contiguous mfn list
to a pv-domain. In order to support sparse memory this mfn list is
accessed via a three level p2m tree built early in the boot process.
Whenever the system needs the mfn associated with a pfn this tree is
used to find the mfn.

Instead of using a software walked tree for accessing a specific mfn
list entry this patch is creating a virtual address area for the
entire possible mfn list including memory holes. The holes are
covered by mapping a pre-defined  page consisting only of "invalid
mfn" entries. Access to a mfn entry is possible by just using the
virtual base address of the mfn list and the pfn as index into that
list. This speeds up the (hot) path of determining the mfn of a
pfn.

Kernel build on a Dell Latitude E6440 (2 cores, HT) in 64 bit Dom0
showed following improvements:

Elapsed time: 32:50 ->  32:35
System:       18:07 ->  17:47
User:        104:00 -> 103:30

Tested with following configurations:
- 64 bit dom0, 8GB RAM
- 64 bit dom0, 128 GB RAM, PCI-area above 4 GB
- 32 bit domU, 512 MB, 8 GB, 43 GB (more wouldn't work even without
                                    the patch)
- 32 bit domU, ballooning up and down
- 32 bit domU, save and restore
- 32 bit domU with PCI passthrough
- 64 bit domU, 8 GB, 2049 MB, 5000 MB
- 64 bit domU, ballooning up and down
- 64 bit domU, save and restore
- 64 bit domU with PCI passthrough
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Signed-off-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
      054954eb
    • Juergen Gross's avatar
      xen: Delay invalidating extra memory · 5b8e7d80
      Juergen Gross authored 
      When the physical memory configuration is initialized the p2m entries
for not pouplated memory pages are set to "invalid". As those pages
are beyond the hypervisor built p2m list the p2m tree has to be
extended.

This patch delays processing the extra memory related p2m entries
during the boot process until some more basic memory management
functions are callable. This removes the need to create new p2m
entries until virtual memory management is available.
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Reviewed-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
      5b8e7d80
    • Juergen Gross's avatar
      xen: Delay remapping memory of pv-domain · 1f3ac86b
      Juergen Gross authored 
      Early in the boot process the memory layout of a pv-domain is changed
to match the E820 map (either the host one for Dom0 or the Xen one)
regarding placement of RAM and PCI holes. This requires removing memory
pages initially located at positions not suitable for RAM and adding
them later at higher addresses where no restrictions apply.

To be able to operate on the hypervisor supported p2m list until a
virtual mapped linear p2m list can be constructed, remapping must
be delayed until virtual memory management is initialized, as the
initial p2m list can't be extended unlimited at physical memory
initialization time due to it's fixed structure.

A further advantage is the reduction in complexity and code volume as
we don't have to be careful regarding memory restrictions during p2m
updates.
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Reviewed-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
      1f3ac86b
  25. 16 Nov, 2014 1 commit
  27. 18 Jul, 2014 1 commit
    • Daniel Kiper's avatar
      arch/x86/xen: Silence compiler warnings · c7341d6a
      Daniel Kiper authored 
      Compiler complains in the following way when x86 32-bit kernel
with Xen support is build:

  CC      arch/x86/xen/enlighten.o
arch/x86/xen/enlighten.c: In function ‘xen_start_kernel’:
arch/x86/xen/enlighten.c:1726:3: warning: right shift count >= width of type [enabled by default]

Such line contains following EFI initialization code:

boot_params.efi_info.efi_systab_hi = (__u32)(__pa(efi_systab_xen) >> 32);

There is no issue if x86 64-bit kernel is build. However, 32-bit case
generate warning (even if that code will not be executed because Xen
does not work on 32-bit EFI platforms) due to __pa() returning unsigned long
type which has 32-bits width. So move whole EFI initialization stuff
to separate function and build it conditionally to avoid above mentioned
warning on x86 32-bit architecture.
Signed-off-by: default avatarDaniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: default avatarKonrad Rzeszutek Wilk <Konrad.wilk@oracle.com>
Signed-off-by: default avatarMatt Fleming <matt.fleming@intel.com>
      c7341d6a
  29. 05 Jun, 2014 1 commit
  31. 12 May, 2014 1 commit
  33. 21 Jan, 2014 1 commit
    • Roger Pau Monne's avatar
      xen/pvh: Set X86_CR0_WP and others in CR0 (v2) · c9f6e997
      Roger Pau Monne authored 
      otherwise we will get for some user-space applications
that use 'clone' with CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID
end up hitting an assert in glibc manifested by:

general protection ip:7f80720d364c sp:7fff98fd8a80 error:0 in
libc-2.13.so[7f807209e000+180000]

This is due to the nature of said operations which sets and clears
the PID.  "In the successful one I can see that the page table of
the parent process has been updated successfully to use a
different physical page, so the write of the tid on
that page only affects the child...

On the other hand, in the failed case, the write seems to happen before
the copy of the original page is done, so both the parent and the child
end up with the same value (because the parent copies the page after
the write of the child tid has already happened)."
(Roger's analysis). The nature of this is due to the Xen's commit
of 51e2cac257ec8b4080d89f0855c498cbbd76a5e5
"x86/pvh: set only minimal cr0 and cr4 flags in order to use paging"
the CR0_WP was removed so COW features of the Linux kernel were not
operating properly.

While doing that also update the rest of the CR0 flags to be inline
with what a baremetal Linux kernel would set them to.

In 'secondary_startup_64' (baremetal Linux) sets:

X86_CR0_PE | X86_CR0_MP | X86_CR0_ET | X86_CR0_NE | X86_CR0_WP |
X86_CR0_AM | X86_CR0_PG

The hypervisor for HVM type guests (which PVH is a bit) sets:
X86_CR0_PE | X86_CR0_ET | X86_CR0_TS
For PVH it specifically sets:
X86_CR0_PG

Which means we need to set the rest: X86_CR0_MP | X86_CR0_NE  |
X86_CR0_WP | X86_CR0_AM to have full parity.
Signed-off-by: default avatarRoger Pau Monne <roger.pau@citrix.com>
Signed-off-by: default avatarMukesh Rathor <mukesh.rathor@oracle.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
[v1: Took out the cr4 writes to be a seperate patch]
[v2: 0-DAY kernel found xen_setup_gdt to be missing a static]
      c9f6e997
  35. 06 Jan, 2014 1 commit
    • Mukesh Rathor's avatar
      xen/pvh: Secondary VCPU bringup (non-bootup CPUs) · 5840c84b
      Mukesh Rathor authored 
      The VCPU bringup protocol follows the PV with certain twists.
From xen/include/public/arch-x86/xen.h:

Also note that when calling DOMCTL_setvcpucontext and VCPU_initialise
for HVM and PVH guests, not all information in this structure is updated:

 - For HVM guests, the structures read include: fpu_ctxt (if
 VGCT_I387_VALID is set), flags, user_regs, debugreg[*]

 - PVH guests are the same as HVM guests, but additionally use ctrlreg[3] to
 set cr3. All other fields not used should be set to 0.

This is what we do. We piggyback on the 'xen_setup_gdt' - but modify
a bit - we need to call 'load_percpu_segment' so that 'switch_to_new_gdt'
can load per-cpu data-structures. It has no effect on the VCPU0.

We also piggyback on the %rdi register to pass in the CPU number - so
that when we bootup a new CPU, the cpu_bringup_and_idle will have
passed as the first parameter the CPU number (via %rdi for 64-bit).
Signed-off-by: default avatarMukesh Rathor <mukesh.rathor@oracle.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      5840c84b
  37. 22 Aug, 2013 1 commit
  39. 06 Aug, 2013 1 commit
  41. 14 Jul, 2013 1 commit
    • Paul Gortmaker's avatar
      x86: delete __cpuinit usage from all x86 files · 148f9bb8
      Paul Gortmaker authored 
      The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications.  For example, the fix in
commit 5e427ec2 ("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.

After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out.  Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.

Note that some harmless section mismatch warnings may result, since
notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c)
are flagged as __cpuinit  -- so if we remove the __cpuinit from
arch specific callers, we will also get section mismatch warnings.
As an intermediate step, we intend to turn the linux/init.h cpuinit
content into no-ops as early as possible, since that will get rid
of these warnings.  In any case, they are temporary and harmless.

This removes all the arch/x86 uses of the __cpuinit macros from
all C files.  x86 only had the one __CPUINIT used in assembly files,
and it wasn't paired off with a .previous or a __FINIT, so we can
delete it directly w/o any corresponding additional change there.

[1] https://lkml.org/lkml/2013/5/20/589

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Acked-by: default avatarIngo Molnar <mingo@kernel.org>
Acked-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: default avatarPaul Gortmaker <paul.gortmaker@windriver.com>
      148f9bb8
  43. 15 Feb, 2013 1 commit
  45. 02 Nov, 2012 1 commit
    • Olaf Hering's avatar
      xen PVonHVM: use E820_Reserved area for shared_info · 9d02b43d
      Olaf Hering authored 
      This is a respin of 00e37bdb
("xen PVonHVM: move shared_info to MMIO before kexec").

Currently kexec in a PVonHVM guest fails with a triple fault because the
new kernel overwrites the shared info page. The exact failure depends on
the size of the kernel image. This patch moves the pfn from RAM into an
E820 reserved memory area.

The pfn containing the shared_info is located somewhere in RAM. This will
cause trouble if the current kernel is doing a kexec boot into a new
kernel. The new kernel (and its startup code) can not know where the pfn
is, so it can not reserve the page. The hypervisor will continue to update
the pfn, and as a result memory corruption occours in the new kernel.

The toolstack marks the memory area FC000000-FFFFFFFF as reserved in the
E820 map. Within that range newer toolstacks (4.3+) will keep 1MB
starting from FE700000 as reserved for guest use. Older Xen4 toolstacks
will usually not allocate areas up to FE700000, so FE700000 is expected
to work also with older toolstacks.

In Xen3 there is no reserved area at a fixed location. If the guest is
started on such old hosts the shared_info page will be placed in RAM. As
a result kexec can not be used.
Signed-off-by: default avatarOlaf Hering <olaf@aepfle.de>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      9d02b43d
  47. 23 Aug, 2012 2 commits
    • Konrad Rzeszutek Wilk's avatar
      xen/p2m: Add logic to revector a P2M tree to use __va leafs. · 357a3cfb
      Konrad Rzeszutek Wilk authored 
      During bootup Xen supplies us with a P2M array. It sticks
it right after the ramdisk, as can be seen with a 128GB PV guest:

(certain parts removed for clarity):
xc_dom_build_image: called
xc_dom_alloc_segment:   kernel       : 0xffffffff81000000 -> 0xffffffff81e43000  (pfn 0x1000 + 0xe43 pages)
xc_dom_pfn_to_ptr: domU mapping: pfn 0x1000+0xe43 at 0x7f097d8bf000
xc_dom_alloc_segment:   ramdisk      : 0xffffffff81e43000 -> 0xffffffff925c7000  (pfn 0x1e43 + 0x10784 pages)
xc_dom_pfn_to_ptr: domU mapping: pfn 0x1e43+0x10784 at 0x7f0952dd2000
xc_dom_alloc_segment:   phys2mach    : 0xffffffff925c7000 -> 0xffffffffa25c7000  (pfn 0x125c7 + 0x10000 pages)
xc_dom_pfn_to_ptr: domU mapping: pfn 0x125c7+0x10000 at 0x7f0942dd2000
xc_dom_alloc_page   :   start info   : 0xffffffffa25c7000 (pfn 0x225c7)
xc_dom_alloc_page   :   xenstore     : 0xffffffffa25c8000 (pfn 0x225c8)
xc_dom_alloc_page   :   console      : 0xffffffffa25c9000 (pfn 0x225c9)
nr_page_tables: 0x0000ffffffffffff/48: 0xffff000000000000 -> 0xffffffffffffffff, 1 table(s)
nr_page_tables: 0x0000007fffffffff/39: 0xffffff8000000000 -> 0xffffffffffffffff, 1 table(s)
nr_page_tables: 0x000000003fffffff/30: 0xffffffff80000000 -> 0xffffffffbfffffff, 1 table(s)
nr_page_tables: 0x00000000001fffff/21: 0xffffffff80000000 -> 0xffffffffa27fffff, 276 table(s)
xc_dom_alloc_segment:   page tables  : 0xffffffffa25ca000 -> 0xffffffffa26e1000  (pfn 0x225ca + 0x117 pages)
xc_dom_pfn_to_ptr: domU mapping: pfn 0x225ca+0x117 at 0x7f097d7a8000
xc_dom_alloc_page   :   boot stack   : 0xffffffffa26e1000 (pfn 0x226e1)
xc_dom_build_image  : virt_alloc_end : 0xffffffffa26e2000
xc_dom_build_image  : virt_pgtab_end : 0xffffffffa2800000

So the physical memory and virtual (using __START_KERNEL_map addresses)
layout looks as so:

  phys                             __ka
/------------\                   /-------------------\
| 0          | empty             | 0xffffffff80000000|
| ..         |                   | ..                |
| 16MB       | <= kernel starts  | 0xffffffff81000000|
| ..         |                   |                   |
| 30MB       | <= kernel ends => | 0xffffffff81e43000|
| ..         |  & ramdisk starts | ..                |
| 293MB      | <= ramdisk ends=> | 0xffffffff925c7000|
| ..         |  & P2M starts     | ..                |
| ..         |                   | ..                |
| 549MB      | <= P2M ends    => | 0xffffffffa25c7000|
| ..         | start_info        | 0xffffffffa25c7000|
| ..         | xenstore          | 0xffffffffa25c8000|
| ..         | cosole            | 0xffffffffa25c9000|
| 549MB      | <= page tables => | 0xffffffffa25ca000|
| ..         |                   |                   |
| 550MB      | <= PGT end     => | 0xffffffffa26e1000|
| ..         | boot stack        |                   |
\------------/                   \-------------------/

As can be seen, the ramdisk, P2M and pagetables are taking
a bit of __ka addresses space. Which is a problem since the
MODULES_VADDR starts at 0xffffffffa0000000 - and P2M sits
right in there! This results during bootup with the inability to
load modules, with this error:

------------[ cut here ]------------
WARNING: at /home/konrad/ssd/linux/mm/vmalloc.c:106 vmap_page_range_noflush+0x2d9/0x370()
Call Trace:
 [<ffffffff810719fa>] warn_slowpath_common+0x7a/0xb0
 [<ffffffff81030279>] ? __raw_callee_save_xen_pmd_val+0x11/0x1e
 [<ffffffff81071a45>] warn_slowpath_null+0x15/0x20
 [<ffffffff81130b89>] vmap_page_range_noflush+0x2d9/0x370
 [<ffffffff81130c4d>] map_vm_area+0x2d/0x50
 [<ffffffff811326d0>] __vmalloc_node_range+0x160/0x250
 [<ffffffff810c5369>] ? module_alloc_update_bounds+0x19/0x80
 [<ffffffff810c6186>] ? load_module+0x66/0x19c0
 [<ffffffff8105cadc>] module_alloc+0x5c/0x60
 [<ffffffff810c5369>] ? module_alloc_update_bounds+0x19/0x80
 [<ffffffff810c5369>] module_alloc_update_bounds+0x19/0x80
 [<ffffffff810c70c3>] load_module+0xfa3/0x19c0
 [<ffffffff812491f6>] ? security_file_permission+0x86/0x90
 [<ffffffff810c7b3a>] sys_init_module+0x5a/0x220
 [<ffffffff815ce339>] system_call_fastpath+0x16/0x1b
---[ end trace fd8f7704fdea0291 ]---
vmalloc: allocation failure, allocated 16384 of 20480 bytes
modprobe: page allocation failure: order:0, mode:0xd2

Since the __va and __ka are 1:1 up to MODULES_VADDR and
cleanup_highmap rids __ka of the ramdisk mapping, what
we want to do is similar - get rid of the P2M in the __ka
address space. There are two ways of fixing this:

 1) All P2M lookups instead of using the __ka address would
    use the __va address. This means we can safely erase from
    __ka space the PMD pointers that point to the PFNs for
    P2M array and be OK.
 2). Allocate a new array, copy the existing P2M into it,
    revector the P2M tree to use that, and return the old
    P2M to the memory allocate. This has the advantage that
    it sets the stage for using XEN_ELF_NOTE_INIT_P2M
    feature. That feature allows us to set the exact virtual
    address space we want for the P2M - and allows us to
    boot as initial domain on large machines.

So we pick option 2).

This patch only lays the groundwork in the P2M code. The patch
that modifies the MMU is called "xen/mmu: Copy and revector the P2M tree."
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      357a3cfb
    • Konrad Rzeszutek Wilk's avatar
      xen/mmu: The xen_setup_kernel_pagetable doesn't need to return anything. · 3699aad0
      Konrad Rzeszutek Wilk authored 
      We don't need to return the new PGD - as we do not use it.
Acked-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      3699aad0
  49. 16 Aug, 2012 1 commit
  51. 14 Sep, 2012 1 commit
  53. 19 Jul, 2012 1 commit
    • Olaf Hering's avatar
      xen PVonHVM: move shared_info to MMIO before kexec · 00e37bdb
      Olaf Hering authored 
      Currently kexec in a PVonHVM guest fails with a triple fault because the
new kernel overwrites the shared info page. The exact failure depends on
the size of the kernel image. This patch moves the pfn from RAM into
MMIO space before the kexec boot.

The pfn containing the shared_info is located somewhere in RAM. This
will cause trouble if the current kernel is doing a kexec boot into a
new kernel. The new kernel (and its startup code) can not know where the
pfn is, so it can not reserve the page. The hypervisor will continue to
update the pfn, and as a result memory corruption occours in the new
kernel.

One way to work around this issue is to allocate a page in the
xen-platform pci device's BAR memory range. But pci init is done very
late and the shared_info page is already in use very early to read the
pvclock. So moving the pfn from RAM to MMIO is racy because some code
paths on other vcpus could access the pfn during the small   window when
the old pfn is moved to the new pfn. There is even a  small window were
the old pfn is not backed by a mfn, and during that time all reads
return -1.

Because it is not known upfront where the MMIO region is located it can
not be used right from the start in xen_hvm_init_shared_info.

To minimise trouble the move of the pfn is done shortly before kexec.
This does not eliminate the race because all vcpus are still online when
the syscore_ops will be called. But hopefully there is no work pending
at this point in time. Also the syscore_op is run last which reduces the
risk further.
Signed-off-by: default avatarOlaf Hering <olaf@aepfle.de>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      00e37bdb
  55. 07 May, 2012 1 commit
    • David Vrabel's avatar
      xen/setup: update VA mapping when releasing memory during setup · 83d51ab4
      David Vrabel authored 
      In xen_memory_setup(), if a page that is being released has a VA
mapping this must also be updated.  Otherwise, the page will be not
released completely -- it will still be referenced in Xen and won't be
freed util the mapping is removed and this prevents it from being
reallocated at a different PFN.

This was already being done for the ISA memory region in
xen_ident_map_ISA() but on many systems this was omitting a few pages
as many systems marked a few pages below the ISA memory region as
reserved in the e820 map.

This fixes errors such as:

(XEN) page_alloc.c:1148:d0 Over-allocation for domain 0: 2097153 > 2097152
(XEN) memory.c:133:d0 Could not allocate order=0 extent: id=0 memflags=0 (0 of 17)
Signed-off-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      83d51ab4
  57. 01 May, 2012 1 commit
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