Commit Graph

15892 Commits

Author SHA1 Message Date
Michael S. Tsirkin 9fc77441e5 KVM: make processes waiting on vcpu mutex killable
vcpu mutex can be held for unlimited time so
taking it with mutex_lock on an ioctl is wrong:
one process could be passed a vcpu fd and
call this ioctl on the vcpu used by another process,
it will then be unkillable until the owner exits.

Call mutex_lock_killable instead and return status.
Note: mutex_lock_interruptible would be even nicer,
but I am not sure all users are prepared to handle EINTR
from these ioctls. They might misinterpret it as an error.

Cleanup paths expect a vcpu that can't be used by
any userspace so this will always succeed - catch bugs
by calling BUG_ON.

Catch callers that don't check return state by adding
__must_check.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-09-17 13:46:32 -03:00
Avi Kivity 7454766f7b KVM: SVM: Make use of asm.h
Use macros for bitness-insensitive register names, instead of
rolling our own.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-09-17 10:38:05 -03:00
Avi Kivity b188c81f2e KVM: VMX: Make use of asm.h
Use macros for bitness-insensitive register names, instead of
rolling our own.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-09-17 10:38:04 -03:00
Avi Kivity 83287ea420 KVM: VMX: Make lto-friendly
LTO (link-time optimization) doesn't like local labels to be referred to
from a different function, since the two functions may be built in separate
compilation units.  Use an external variable instead.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-09-17 10:38:03 -03:00
Takuya Yoshikawa ecba9a52ac KVM: x86: lapic: Clean up find_highest_vector() and count_vectors()
find_highest_vector() and count_vectors():
 - Instead of using magic values, define and use proper macros.

find_highest_vector():
 - Remove likely() which is there only for historical reasons and not
   doing correct branch predictions anymore.  Using such heuristics
   to optimize this function is not worth it now.  Let CPUs predict
   things instead.

 - Stop checking word[0] separately.  This was only needed for doing
   likely() optimization.

 - Use for loop, not while, to iterate over the register array to make
   the code clearer.

Note that we actually confirmed that the likely() did wrong predictions
by inserting debug code.

Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-09-12 13:38:23 -03:00
Xiao Guangrong 7de5bdc96c KVM: MMU: remove unnecessary check
Checking the return of kvm_mmu_get_page is unnecessary since it is
guaranteed by memory cache

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-09-10 11:26:16 +03:00
Liu, Jinsong 92b5265d38 KVM: Depend on HIGH_RES_TIMERS
KVM lapic timer and tsc deadline timer based on hrtimer,
setting a leftmost node to rb tree and then do hrtimer reprogram.
If hrtimer not configured as high resolution, hrtimer_enqueue_reprogram
do nothing and then make kvm lapic timer and tsc deadline timer fail.

Signed-off-by: Liu, Jinsong <jinsong.liu@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-09-10 11:10:03 +03:00
Michael S. Tsirkin a50abc3b2b KVM: use symbolic constant for nr interrupts
interrupt_bitmap is KVM_NR_INTERRUPTS bits in size,
so just use that instead of hard-coded constants
and math.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-09-06 18:37:44 +03:00
Gleb Natapov b3356bf0db KVM: emulator: optimize "rep ins" handling
Optimize "rep ins" by allowing emulator to write back more than one
datum at a time. Introduce new operand type OP_MEM_STR which tells
writeback() that dst contains pointer to an array that should be written
back as opposite to just one data element.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-09-06 18:07:38 +03:00
Gleb Natapov f3bd64c68a KVM: emulator: string_addr_inc() cleanup
Remove unneeded segment argument. Address structure already has correct
segment which was put there during decode.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-09-06 18:07:01 +03:00
Gleb Natapov 9d1b39a967 KVM: emulator: make x86 emulation modes enum instead of defines
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-09-06 18:07:01 +03:00
Gleb Natapov 716d51abff KVM: Provide userspace IO exit completion callback
Current code assumes that IO exit was due to instruction emulation
and handles execution back to emulator directly. This patch adds new
userspace IO exit completion callback that can be set by any other code
that caused IO exit to userspace.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-09-06 18:06:37 +03:00
Marcelo Tosatti 3b4dc3a031 KVM: move postcommit flush to x86, as mmio sptes are x86 specific
Other arches do not need this.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

v2: fix incorrect deletion of mmio sptes on gpa move (noticed by Takuya)
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-09-06 16:37:30 +03:00
Marcelo Tosatti 2df72e9bc4 KVM: split kvm_arch_flush_shadow
Introducing kvm_arch_flush_shadow_memslot, to invalidate the
translations of a single memory slot.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-09-06 16:37:25 +03:00
Mathias Krause 09941fbb71 KVM: SVM: constify lookup tables
We never modify direct_access_msrs[], msrpm_ranges[],
svm_exit_handlers[] or x86_intercept_map[] at runtime.
Mark them r/o.

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-09-05 12:42:14 +03:00
Mathias Krause 772e031899 KVM: VMX: constify lookup tables
We use vmcs_field_to_offset_table[], kvm_vmx_segment_fields[] and
kvm_vmx_exit_handlers[] as lookup tables only -- make them r/o.

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-09-05 12:42:09 +03:00
Mathias Krause f1d248315a KVM: x86: more constification
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-09-05 12:42:02 +03:00
Mathias Krause 0fbe9b0b19 KVM: x86: constify read_write_emulator_ops
We never change those, make them r/o.

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-09-05 12:41:54 +03:00
Mathias Krause 0225fb509d KVM: x86 emulator: constify emulate_ops
We never change emulate_ops[] at runtime so it should be r/o.

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-09-05 12:41:48 +03:00
Mathias Krause fd0a0d8208 KVM: x86 emulator: mark opcode tables const
The opcode tables never change at runtime, therefor mark them const.

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-09-05 12:41:28 +03:00
Mathias Krause 89a87c6779 KVM: x86 emulator: use aligned variants of SSE register ops
As the the compiler ensures that the memory operand is always aligned
to a 16 byte memory location, use the aligned variant of MOVDQ for
read_sse_reg() and write_sse_reg().

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-09-05 12:41:11 +03:00
Mathias Krause 326d07cb30 KVM: x86: minor size optimization
Some fields can be constified and/or made static to reduce code and data
size.

Numbers for a 32 bit build:

        text    data     bss     dec     hex filename
before: 3351      80       0    3431     d67 cpuid.o
 after: 3391       0       0    3391     d3f cpuid.o

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-09-05 12:41:09 +03:00
Gleb Natapov ec798660cf KVM: cleanup pic reset
kvm_pic_reset() is not used anywhere. Move reset logic from
pic_ioport_write() there.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-09-04 14:53:51 +03:00
Marcelo Tosatti 9a7819774e KVM: x86: remove unused variable from kvm_task_switch()
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-08-30 17:45:54 -03:00
Avi Kivity a81aba14dc KVM: VMX: Ignore segment G and D bits when considering whether we can virtualize
We will enter the guest with G and D cleared; as real hardware ignores D in
real mode, and G is taken care of by the limit test, we allow more code to
run in vm86 mode.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-08-27 20:02:21 -03:00
Avi Kivity ce56680347 KVM: VMX: Save all segment data in real mode
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-08-27 20:02:21 -03:00
Avi Kivity 1390a28b27 KVM: VMX: Preserve segment limit and access rights in real mode
While this is undocumented, real processors do not reload the segment
limit and access rights when loading a segment register in real mode.
Real programs rely on it so we need to comply with this behaviour.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-08-27 20:02:21 -03:00
Avi Kivity 7263642028 KVM: VMX: Return real real-mode segment data even if emulate_invalid_guest_state=1
emulate_invalid_guest_state=1 doesn't mean we don't munge the segments in the
vmcs; we do.  So we need to return the real ones (maintained by vmx_set_segment).

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-08-27 20:02:21 -03:00
Avi Kivity 0afbe2f878 KVM: x86 emulator: Fix #GP error code during linearization
We want the segment selector, nor segment number.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-08-27 20:02:20 -03:00
Avi Kivity a5625189f6 KVM: x86 emulator: Check segment limits in real mode too
Segment limits are verified in real mode, not just protected mode.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-08-27 20:02:20 -03:00
Avi Kivity 03ebebeb1f KVM: x86 emulator: Leave segment limit and attributs alone in real mode
When loading a segment in real mode, only the base and selector must
be modified.  The limit needs to be left alone, otherwise big real mode
users will hit a #GP due to limit checking (currently this is suppressed
because we don't check limits in real mode).

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-08-27 20:02:20 -03:00
Avi Kivity e2a610d7fc KVM: VMX: Allow vm86 virtualization of big real mode
Usually, big real mode uses large (4GB) segments.  Currently we don't
virtualize this; if any segment has a limit other than 0xffff, we emulate.
But if we set the vmx-visible limit to 0xffff, we can use vm86 to virtualize
real mode; if an access overruns the segment limit, the guest will #GP, which
we will trap and forward to the emulator.  This results in significantly
faster execution, and less risk of hitting an unemulated instruction.

If the limit is less than 0xffff, we retain the existing behaviour.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-08-27 20:02:20 -03:00
Avi Kivity 495e116684 KVM: VMX: Allow real mode emulation using vm86 with dpl=0
Real mode is always entered from protected mode with dpl=0.  Since
the dpl doesn't affect execution, and we already override it to 3
in the vmcs (as vmx requires), we can allow execution in that state.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-08-27 20:02:20 -03:00
Avi Kivity c865c43de6 KVM: VMX: Retain limit and attributes when entering protected mode
Real processors don't change segment limits and attributes while in
real mode.  Mimic that behaviour.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-08-27 20:02:20 -03:00
Avi Kivity f5f7b2fe3b KVM: VMX: Use kvm_segment to save protected-mode segments when entering realmode
Instead of using struct kvm_save_segment, use struct kvm_segment, which is what
the other APIs use.  This leads to some simplification.

We replace save_rmode_seg() with a call to vmx_save_segment().  Since this depends
on rmode.vm86_active, we move the call to before setting the flag.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-08-27 20:02:19 -03:00
Avi Kivity 72fbefec26 KVM: VMX: Fix incorrect lookup of segment S flag in fix_pmode_dataseg()
fix_pmode_dataseg() looks up S in ->base instead of ->ar_bytes.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-08-27 20:02:19 -03:00
Avi Kivity baa7e81e32 KVM: VMX: Separate saving pre-realmode state from setting segments
Commit b246dd5df1 ("KVM: VMX: Fix KVM_SET_SREGS with big real mode
segments") moved fix_rmode_seg() to vmx_set_segment(), so that it is
applied not just on transitions to real mode, but also on KVM_SET_SREGS
(migration).  However fix_rmode_seg() not only munges the vmcs segments,
it also sets up the save area for us to restore when returning to
protected mode or to return in vmx_get_segment().

Move saving the segment into a new function, save_rmode_seg(), and
call it just during the transition.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-08-27 20:02:19 -03:00
Avi Kivity dd856efafe KVM: x86 emulator: access GPRs on demand
Instead of populating the entire register file, read in registers
as they are accessed, and write back only the modified ones.  This
saves a VMREAD and VMWRITE on Intel (for rsp, since it is not usually
used during emulation), and a two 128-byte copies for the registers.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-08-27 18:38:55 -03:00
Marcelo Tosatti c78aa4c4b9 Merge remote-tracking branch 'upstream/master' into queue
Merging critical fixes from upstream required for development.

* upstream/master: (809 commits)
  libata: Add a space to " 2GB ATA Flash Disk" DMA blacklist entry
  Revert "powerpc: Update g5_defconfig"
  powerpc/perf: Use pmc_overflow() to detect rolled back events
  powerpc: Fix VMX in interrupt check in POWER7 copy loops
  powerpc: POWER7 copy_to_user/copy_from_user patch applied twice
  powerpc: Fix personality handling in ppc64_personality()
  powerpc/dma-iommu: Fix IOMMU window check
  powerpc: Remove unnecessary ifdefs
  powerpc/kgdb: Restore current_thread_info properly
  powerpc/kgdb: Bail out of KGDB when we've been triggered
  powerpc/kgdb: Do not set kgdb_single_step on ppc
  powerpc/mpic_msgr: Add missing includes
  powerpc: Fix null pointer deref in perf hardware breakpoints
  powerpc: Fixup whitespace in xmon
  powerpc: Fix xmon dl command for new printk implementation
  xfs: check for possible overflow in xfs_ioc_trim
  xfs: unlock the AGI buffer when looping in xfs_dialloc
  xfs: fix uninitialised variable in xfs_rtbuf_get()
  powerpc/fsl: fix "Failed to mount /dev: No such device" errors
  powerpc/fsl: update defconfigs
  ...

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-08-26 13:58:41 -03:00
Linus Torvalds 267560874c Three bug-fixes:
- Revert the kexec fix which caused on non-kexec shutdowns a race.
  - Reuse existing P2M leafs - instead of requiring to allocate a large
    area of bootup virtual address estate.
  - Fix a one-off error when adding PFNs for balloon pages.
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1.4.12 (GNU/Linux)
 
 iQEcBAABAgAGBQJQNppKAAoJEFjIrFwIi8fJU/oH/jdWdRqJgC5mCnu9LwrIemEj
 gPTAcKw01A/2vbOY5rfXx7rCpgeU5ZM/XSt0byz/J5q0bmjjKVM106Smq1s7EaQx
 OjsdLglWoZYzKJjXH/FEKRPD39f/hd+KNJu3aGEJM8UZ0htvxlg6ACGzVPJa83Pf
 yrRXSycxvEevbGbuwWdNubxD5WKMMmbzi/HGGfdtL4256d0xIgxMrYgskLek96cR
 cg11llC5QLzH8mX+M5iX0lchASvMITyERXyEKK2opFN8a/766yi16agP75RKZdkP
 kWXp0vyOMrpy9UnOs2V1XLc/ufqNwHLcPVfecScXhz8xZWrZYOBdJQf7HAWxvLE=
 =MgvT
 -----END PGP SIGNATURE-----

Merge tag 'stable/for-linus-3.6-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen

Pull three xen bug-fixes from Konrad Rzeszutek Wilk:
 - Revert the kexec fix which caused on non-kexec shutdowns a race.
 - Reuse existing P2M leafs - instead of requiring to allocate a large
   area of bootup virtual address estate.
 - Fix a one-off error when adding PFNs for balloon pages.

* tag 'stable/for-linus-3.6-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen/setup: Fix one-off error when adding for-balloon PFNs to the P2M.
  xen/p2m: Reuse existing P2M leafs if they are filled with 1:1 PFNs or INVALID.
  Revert "xen PVonHVM: move shared_info to MMIO before kexec"
2012-08-25 17:31:59 -07:00
Linus Torvalds 6ec9776c28 Merge git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm fixes from Marcelo Tosatti.

* git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: x86 emulator: use stack size attribute to mask rsp in stack ops
  KVM: MMU: Fix mmu_shrink() so that it can free mmu pages as intended
  ppc: e500_tlb memset clears nothing
  KVM: PPC: Add cache flush on page map
  KVM: PPC: Book3S HV: Fix incorrect branch in H_CEDE code
  KVM: x86: update KVM_SAVE_MSRS_BEGIN to correct value
2012-08-25 17:27:17 -07:00
Konrad Rzeszutek Wilk c96aae1f7f xen/setup: Fix one-off error when adding for-balloon PFNs to the P2M.
When we are finished with return PFNs to the hypervisor, then
populate it back, and also mark the E820 MMIO and E820 gaps
as IDENTITY_FRAMEs, we then call P2M to set areas that can
be used for ballooning. We were off by one, and ended up
over-writting a P2M entry that most likely was an IDENTITY_FRAME.
For example:

1-1 mapping on 40000->40200
1-1 mapping on bc558->bc5ac
1-1 mapping on bc5b4->bc8c5
1-1 mapping on bc8c6->bcb7c
1-1 mapping on bcd00->100000
Released 614 pages of unused memory
Set 277889 page(s) to 1-1 mapping
Populating 40200-40466 pfn range: 614 pages added

=> here we set from 40466 up to bc559 P2M tree to be
INVALID_P2M_ENTRY. We should have done it up to bc558.

The end result is that if anybody is trying to construct
a PTE for PFN bc558 they end up with ~PAGE_PRESENT.

CC: stable@vger.kernel.org
Reported-by-and-Tested-by: Andre Przywara <andre.przywara@amd.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-08-23 10:14:52 -04:00
Marcelo Tosatti 90993cdd18 x86: KVM guest: merge CONFIG_KVM_CLOCK into CONFIG_KVM_GUEST
The distinction between CONFIG_KVM_CLOCK and CONFIG_KVM_GUEST is
not so clear anymore, as demonstrated by recent bugs caused by poor
handling of on/off combinations of these options.

Merge CONFIG_KVM_CLOCK into CONFIG_KVM_GUEST.

Reported-By: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-08-23 04:57:54 -03:00
Andreas Herrmann 36bf50d769 x86, microcode, AMD: Fix broken ucode patch size check
This issue was recently observed on an AMD C-50 CPU where a patch of
maximum size was applied.

Commit be62adb492 ("x86, microcode, AMD: Simplify ucode verification")
added current_size in get_matching_microcode(). This is calculated as
size of the ucode patch + 8 (ie. size of the header). Later this is
compared against the maximum possible ucode patch size for a CPU family.
And of course this fails if the patch has already maximum size.

Cc: <stable@vger.kernel.org> [3.3+]
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Link: http://lkml.kernel.org/r/1344361461-10076-1-git-send-email-bp@amd64.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2012-08-22 16:10:41 -07:00
Avi Kivity 5ad105e569 KVM: x86 emulator: use stack size attribute to mask rsp in stack ops
The sub-register used to access the stack (sp, esp, or rsp) is not
determined by the address size attribute like other memory references,
but by the stack segment's B bit (if not in x86_64 mode).

Fix by using the existing stack_mask() to figure out the correct mask.

This long-existing bug was exposed by a combination of a27685c33a
(emulate invalid guest state by default), which causes many more
instructions to be emulated, and a seabios change (possibly a bug) which
causes the high 16 bits of esp to become polluted across calls to real
mode software interrupts.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-08-22 18:54:26 -03:00
Takuya Yoshikawa 35f2d16bb9 KVM: MMU: Fix mmu_shrink() so that it can free mmu pages as intended
Although the possible race described in

  commit 85b7059169
  KVM: MMU: fix shrinking page from the empty mmu

was correct, the real cause of that issue was a more trivial bug of
mmu_shrink() introduced by

  commit 1952639665
  KVM: MMU: do not iterate over all VMs in mmu_shrink()

Here is the bug:

	if (kvm->arch.n_used_mmu_pages > 0) {
		if (!nr_to_scan--)
			break;
		continue;
	}

We skip VMs whose n_used_mmu_pages is not zero and try to shrink others:
in other words we try to shrink empty ones by mistake.

This patch reverses the logic so that mmu_shrink() can free pages from
the first VM whose n_used_mmu_pages is not zero.  Note that we also add
comments explaining the role of nr_to_scan which is not practically
important now, hoping this will be improved in the future.

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Cc: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-08-22 15:27:13 +03:00
Xiao Guangrong 4d8b81abc4 KVM: introduce readonly memslot
In current code, if we map a readonly memory space from host to guest
and the page is not currently mapped in the host, we will get a fault
pfn and async is not allowed, then the vm will crash

We introduce readonly memory region to map ROM/ROMD to the guest, read access
is happy for readonly memslot, write access on readonly memslot will cause
KVM_EXIT_MMIO exit

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-08-22 15:09:03 +03:00
Xiao Guangrong 037d92dc5d KVM: introduce gfn_to_pfn_memslot_atomic
It can instead of hva_to_pfn_atomic

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-08-22 15:08:52 +03:00
Xiao Guangrong 8e3d9d061b KVM: x86: fix possible infinite loop caused by reexecute_instruction
Currently, we reexecute all unhandleable instructions if they do not
access on the mmio, however, it can not work if host map the readonly
memory to guest. If the instruction try to write this kind of memory,
it will fault again when guest retry it, then we will goto a infinite
loop: retry instruction -> write #PF -> emulation fail ->
retry instruction -> ...

Fix it by retrying the instruction only when it faults on the writable
memory

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-08-22 15:08:49 +03:00
Avi Kivity cb09cad44f x86/alternatives: Fix p6 nops on non-modular kernels
Probably a leftover from the early days of self-patching, p6nops
are marked __initconst_or_module, which causes them to be
discarded in a non-modular kernel.  If something later triggers
patching, it will overwrite kernel code with garbage.

Reported-by: Tomas Racek <tracek@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Cc: Michael Tokarev <mjt@tls.msk.ru>
Cc: Borislav Petkov <borislav.petkov@amd.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: qemu-devel@nongnu.org
Cc: Anthony Liguori <anthony@codemonkey.ws>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Alan Cox <alan@linux.intel.com>
Link: http://lkml.kernel.org/r/5034AE84.90708@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-08-22 12:09:49 +02:00