KVM: Return EFAULT from kvm ioctl when guest accesses bad area
Currently if guest access address that belongs to memory slot but is not
backed up by page or page is read only KVM treats it like MMIO access.
Remove that capability. It was never part of the interface and should
not be relied upon.
Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Avi Kivity [Sun, 6 Jun 2010 12:46:44 +0000 (15:46 +0300)]
KVM: MMU: Don't drop accessed bit while updating an spte
__set_spte() will happily replace an spte with the accessed bit set with
one that has the accessed bit clear. Add a helper update_spte() which checks
for this condition and updates the page flag if needed.
Avi Kivity [Sun, 6 Jun 2010 11:48:06 +0000 (14:48 +0300)]
KVM: MMU: Atomically check for accessed bit when dropping an spte
Currently, in the window between the check for the accessed bit, and actually
dropping the spte, a vcpu can access the page through the spte and set the bit,
which will be ignored by the mmu.
Fix by using an exchange operation to atmoically fetch the spte and drop it.
Avi Kivity [Sun, 6 Jun 2010 11:31:27 +0000 (14:31 +0300)]
KVM: MMU: Introduce drop_spte()
When we call rmap_remove(), we (almost) always immediately follow it by
an __set_spte() to a nonpresent pte. Since we need to perform the two
operations atomically, to avoid losing the dirty and accessed bits, introduce
a helper drop_spte() and convert all call sites.
Commit 341d9b535b6c simplify reload logic while entry guest mode, it
can avoid unnecessary sync-root if KVM_REQ_MMU_RELOAD and
KVM_REQ_MMU_SYNC both set.
But, it cause a issue that when we handle 'KVM_REQ_TLB_FLUSH', the
root is invalid, it is triggered during my test:
Kernel BUG at ffffffffa00212b8 [verbose debug info unavailable]
......
Fixed by directly return if the root is not ready.
For 32bit machines where the physical address width is
larger than the virtual address width the frame number types
in KVM may overflow. Fix this by changing them to u64.
This patch converts unnecessary divide and modulo operations
in the KVM large page related code into logical operations.
This allows to convert gfn_t to u64 while not breaking 32
bit builds.
Alexander Graf [Wed, 30 Jun 2010 13:18:46 +0000 (15:18 +0200)]
KVM: PPC: Make use of hash based Shadow MMU
We just introduced generic functions to handle shadow pages on PPC.
This patch makes the respective backends make use of them, getting
rid of a lot of duplicate code along the way.
Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Alexander Graf [Wed, 30 Jun 2010 13:18:45 +0000 (15:18 +0200)]
KVM: PPC: Add generic hpte management functions
Currently the shadow paging code keeps an array of entries it knows about.
Whenever the guest invalidates an entry, we loop through that entry,
trying to invalidate matching parts.
While this is a really simple implementation, it is probably the most
ineffective one possible. So instead, let's keep an array of lists around
that are indexed by a hash. This way each PTE can be added by 4 list_add,
removed by 4 list_del invocations and the search only needs to loop through
entries that share the same hash.
This patch implements said lookup and exports generic functions that both
the 32-bit and 64-bit backend can use.
Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Xiao Guangrong [Wed, 30 Jun 2010 08:03:28 +0000 (16:03 +0800)]
KVM: MMU: fix direct sp's access corrupted
If the mapping is writable but the dirty flag is not set, we will find
the read-only direct sp and setup the mapping, then if the write #PF
occur, we will mark this mapping writable in the read-only direct sp,
now, other real read-only mapping will happily write it without #PF.
It may hurt guest's COW
Fixed by re-install the mapping when write #PF occur.
Xiao Guangrong [Wed, 30 Jun 2010 08:02:45 +0000 (16:02 +0800)]
KVM: MMU: fix conflict access permissions in direct sp
In no-direct mapping, we mark sp is 'direct' when we mapping the
guest's larger page, but its access is encoded form upper page-struct
entire not include the last mapping, it will cause access conflict.
For example, have this mapping:
[W]
/ PDE1 -> |---|
P[W] | | LPA
\ PDE2 -> |---|
[R]
P have two children, PDE1 and PDE2, both PDE1 and PDE2 mapping the
same lage page(LPA). The P's access is WR, PDE1's access is WR,
PDE2's access is RO(just consider read-write permissions here)
When guest access PDE1, we will create a direct sp for LPA, the sp's
access is from P, is W, then we will mark the ptes is W in this sp.
Then, guest access PDE2, we will find LPA's shadow page, is the same as
PDE's, and mark the ptes is RO.
So, if guest access PDE1, the incorrect #PF is occured.
Fixed by encode the last mapping access into direct shadow page
Xiao Guangrong [Wed, 30 Jun 2010 08:02:02 +0000 (16:02 +0800)]
KVM: MMU: fix writable sync sp mapping
While we sync many unsync sp at one time(in mmu_sync_children()),
we may mapping the spte writable, it's dangerous, if one unsync
sp's mapping gfn is another unsync page's gfn.
For example:
SP1.pte[0] = P
SP2.gfn's pfn = P
[SP1.pte[0] = SP2.gfn's pfn]
First, we write protected SP1 and SP2, but SP1 and SP2 are still the
unsync sp.
Then, sync SP1 first, it will detect SP1.pte[0].gfn only has one unsync-sp,
that is SP2, so it will mapping it writable, but we plan to sync SP2 soon,
at this point, the SP2->unsync is not reliable since later we sync SP2 but
SP2->gfn is already writable.
So the final result is: SP2 is the sync page but SP2.gfn is writable.
This bug will corrupt guest's page table, fixed by mark read-only mapping
if the mapped gfn has shadow pages.
Sheng Yang [Wed, 30 Jun 2010 04:25:15 +0000 (12:25 +0800)]
KVM: VMX: Execute WBINVD to keep data consistency with assigned devices
Some guest device driver may leverage the "Non-Snoop" I/O, and explicitly
WBINVD or CLFLUSH to a RAM space. Since migration may occur before WBINVD or
CLFLUSH, we need to maintain data consistency either by:
1: flushing cache (wbinvd) when the guest is scheduled out if there is no
wbinvd exit, or
2: execute wbinvd on all dirty physical CPUs when guest wbinvd exits.
Chris Lalancette [Mon, 21 Jun 2010 15:29:40 +0000 (11:29 -0400)]
KVM: Search the LAPIC's for one that will accept a PIC interrupt
Older versions of 32-bit linux have a "Checking 'hlt' instruction"
test where they repeatedly call the 'hlt' instruction, and then
expect a timer interrupt to kick the CPU out of halt. This happens
before any LAPIC or IOAPIC setup happens, which means that all of
the APIC's are in virtual wire mode at this point. Unfortunately,
the current implementation of virtual wire mode is hardcoded to
only kick the BSP, so if a crash+kexec occurs on a different
vcpu, it will never get kicked.
This patch makes pic_unlock() do the equivalent of
kvm_irq_delivery_to_apic() for the IOAPIC code. That is, it runs
through all of the vcpus looking for one that is in virtual wire
mode. In the normal case where LAPICs and IOAPICs are configured,
this won't be used at all. In the bootstrap phase of a modern
OS, before the LAPICs and IOAPICs are configured, this will have
exactly the same behavior as today; VCPU0 is always looked at
first, so it will always get out of the loop after the first
iteration. This will only go through the loop more than once
during a kexec/kdump, in which case it will only do it a few times
until the kexec'ed kernel programs the LAPIC and IOAPIC.
Signed-off-by: Chris Lalancette <clalance@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Takuya Yoshikawa [Wed, 23 Jun 2010 06:00:29 +0000 (15:00 +0900)]
KVM: ia64: cleanup kvm_ia64_sync_dirty_log()
kvm_ia64_sync_dirty_log() is a helper function for kvm_vm_ioctl_get_dirty_log()
which copies ia64's arch specific dirty bitmap to general one in memslot.
So doing sanity checks in this function is unnatural. We move these checks
outside of this and change the prototype appropriately.
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Signed-off-by: Avi Kivity <avi@redhat.com>
Alexander Graf [Mon, 21 Jun 2010 13:24:55 +0000 (15:24 +0200)]
KVM: PPC: Make BAT only guest segments work
When a guest sets its SR entry to invalid, we may still find a
corresponding entry in a BAT. So we need to make sure we're not
faulting on invalid SR entries, but instead just claim them to be
BAT resolved.
This resolves breakage experienced when using libogc based guests.
Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
Huang Ying [Tue, 22 Jun 2010 06:23:11 +0000 (14:23 +0800)]
KVM: Fix a race condition for usage of is_hwpoison_address()
is_hwpoison_address accesses the page table, so the caller must hold
current->mm->mmap_sem in read mode. So fix its usage in hva_to_pfn of
kvm accordingly.
Comment is_hwpoison_address to remind other users.
Reported-by: Avi Kivity <avi@redhat.com> Signed-off-by: Huang Ying <ying.huang@intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Sheng Yang [Tue, 22 Jun 2010 05:49:21 +0000 (13:49 +0800)]
KVM: x86: Enable AVX for guest
Enable Intel(R) Advanced Vector Extension(AVX) for guest.
The detection of AVX feature includes OSXSAVE bit testing. When OSXSAVE bit is
not set, even if AVX is supported, the AVX instruction would result in UD as
well. So we're safe to expose AVX bits to guest directly.
Signed-off-by: Sheng Yang <sheng@linux.intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Avi Kivity [Mon, 21 Jun 2010 07:57:45 +0000 (10:57 +0300)]
KVM: Prevent internal slots from being COWed
If a process with a memory slot is COWed, the page will change its address
(despite having an elevated reference count). This breaks internal memory
slots which have their physical addresses loaded into vmcs registers (see
the APIC access memory slot).
Newer (guest) kernels use sigp sense running in their spinlock
implementation to check if the other cpu is running before yielding
the processor. This revealed some wrong guest settings, causing
unnecessary exits for every sigp sense running.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Wei Yongjun [Thu, 17 Jun 2010 09:33:55 +0000 (17:33 +0800)]
KVM: x86 emulator: fix group3 instruction decoding
Group 3 instruction with ModRM reg field as 001 is
defined as test instruction under AMD arch, and
emulate_grp3() is ready for emulate it, so fix the
decoding.
static inline int emulate_grp3(...)
{
...
switch (c->modrm_reg) {
case 0 ... 1: /* test */
emulate_2op_SrcV("test", c->src, c->dst, ctxt->eflags);
...
}
Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Asias He [Sat, 19 Jun 2010 08:52:12 +0000 (16:52 +0800)]
KVM: PPC: fix uninitialized variable warning in kvm_ppc_core_deliver_interrupts
Fixes:
arch/powerpc/kvm/booke.c: In function 'kvmppc_core_deliver_interrupts':
arch/powerpc/kvm/booke.c:147: warning: 'msr_mask' may be used uninitialized in this function
Signed-off-by: Asias He <asias.hejun@gmail.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Chris Lalancette [Wed, 16 Jun 2010 21:11:11 +0000 (17:11 -0400)]
KVM: x86: Introduce a workqueue to deliver PIT timer interrupts
We really want to "kvm_set_irq" during the hrtimer callback,
but that is risky because that is during interrupt context.
Instead, offload the work to a workqueue, which is a bit safer
and should provide most of the same functionality.
Signed-off-by: Chris Lalancette <clalance@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Xiao Guangrong [Fri, 11 Jun 2010 13:35:15 +0000 (21:35 +0800)]
KVM: MMU: don't walk every parent pages while mark unsync
While we mark the parent's unsync_child_bitmap, if the parent is already
unsynced, it no need walk it's parent, it can reduce some unnecessary
workload
Xiao Guangrong [Fri, 11 Jun 2010 13:34:04 +0000 (21:34 +0800)]
KVM: MMU: clear unsync_child_bitmap completely
In current code, some page's unsync_child_bitmap is not cleared completely
in mmu_sync_children(), for example, if two PDPEs shard one PDT, one of
PDPE's unsync_child_bitmap is not cleared.
Currently, it not harm anything just little overload, but it's the prepare
work for the later patch
Denis Kirjanov [Fri, 11 Jun 2010 11:23:26 +0000 (11:23 +0000)]
KVM: PPC: fix build warning in kvm_arch_vcpu_ioctl_run
Fix compile warning:
CC [M] arch/powerpc/kvm/powerpc.o
arch/powerpc/kvm/powerpc.c: In function 'kvm_arch_vcpu_ioctl_run':
arch/powerpc/kvm/powerpc.c:290: warning: 'gpr' may be used uninitialized in this function
arch/powerpc/kvm/powerpc.c:290: note: 'gpr' was declared here
Xiao Guangrong [Tue, 8 Jun 2010 12:07:01 +0000 (20:07 +0800)]
KVM: MMU: delay local tlb flush
delay local tlb flush until enter guest moden, it can reduce vpid flush
frequency and reduce remote tlb flush IPI(if KVM_REQ_TLB_FLUSH bit is
already set, IPI is not sent)
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Xiao Guangrong [Fri, 4 Jun 2010 13:54:38 +0000 (21:54 +0800)]
KVM: MMU: don't get free page number in the loop
In the later patch, we will modify sp's zapping way like below:
kvm_mmu_prepare_zap_page A
kvm_mmu_prepare_zap_page B
kvm_mmu_prepare_zap_page C
....
kvm_mmu_commit_zap_page
[ zaped multiple sps only need to call kvm_mmu_commit_zap_page once ]
In __kvm_mmu_free_some_pages() function, the free page number is
getted form 'vcpu->kvm->arch.n_free_mmu_pages' in loop, it will
hinders us to apply kvm_mmu_prepare_zap_page() and kvm_mmu_commit_zap_page()
since kvm_mmu_prepare_zap_page() not free sp.
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Mohammed Gamal [Mon, 31 May 2010 19:40:54 +0000 (22:40 +0300)]
KVM: VMX: Properly return error to userspace on vmentry failure
The vmexit handler returns KVM_EXIT_UNKNOWN since there is no handler
for vmentry failures. This intercepts vmentry failures and returns
KVM_FAIL_ENTRY to userspace instead.
Signed-off-by: Mohammed Gamal <m.gamal005@gmail.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Zachary Amsden [Thu, 27 May 2010 01:09:43 +0000 (15:09 -1000)]
KVM: SVM: Fix EFER.LME being stripped
Must set VCPU register to be the guest notion of EFER even if that
setting is not valid on hardware. This was masked by the set in
set_efer until 7657fd5ace88e8092f5f3a84117e093d7b893f26 broke that.
Fix is simply to set the VCPU register before stripping bits.
Signed-off-by: Zachary Amsden <zamsden@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Lai Jiangshan [Wed, 26 May 2010 08:48:19 +0000 (16:48 +0800)]
KVM: MMU: calculate correct gfn for small host pages backing large guest pages
In Documentation/kvm/mmu.txt:
gfn:
Either the guest page table containing the translations shadowed by this
page, or the base page frame for linear translations. See role.direct.
But in function FNAME(fetch)(), sp->gfn is incorrect when one of following
situations occurred:
1) guest is 32bit paging and the guest PDE maps a 4-MByte page
(backed by 4k host pages), FNAME(fetch)() miss handling the quadrant.
And if guest use pse-36, "table_gfn = gpte_to_gfn(gw->ptes[level - delta]);"
is incorrect.
2) guest is long mode paging and the guest PDPTE maps a 1-GByte page
(backed by 4k or 2M host pages).
So we fix it to suit to the document and suit to the code which
requires sp->gfn correct when sp->role.direct=1.
We use the goal mapping gfn(gw->gfn) to calculate the base page frame
for linear translations, it is simple and easy to be understood.
Reported-by: Marcelo Tosatti <mtosatti@redhat.com> Reported-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com> Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Avi Kivity <avi@redhat.com>
projects / linux-beck.git / log