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| author | Igor Mammedov <imammedo@redhat.com> | 2015-09-18 15:39:05 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2015-09-18 16:49:02 +0200 |
| commit | ebae871a509d3c24b32ff67af2671dadffc58770 (patch) | |
| tree | bf8c940f4338592156c7dad4c708d86db13a3561 /arch | |
| parent | 00cc1633816de8c95f337608a1ea64e228faf771 (diff) | |
| download | linux-ebae871a509d3c24b32ff67af2671dadffc58770.tar.bz2 | |
kvm: svm: reset mmu on VCPU reset
When INIT/SIPI sequence is sent to VCPU which before that
was in use by OS, VMRUN might fail with:
KVM: entry failed, hardware error 0xffffffff
EAX=00000000 EBX=00000000 ECX=00000000 EDX=000006d3
ESI=00000000 EDI=00000000 EBP=00000000 ESP=00000000
EIP=00000000 EFL=00000002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0000 00000000 0000ffff 00009300
CS =9a00 0009a000 0000ffff 00009a00
[...]
CR0=60000010 CR2=b6f3e000 CR3=01942000 CR4=000007e0
[...]
EFER=0000000000000000
with corresponding SVM error:
KVM: FAILED VMRUN WITH VMCB:
[...]
cpl: 0 efer: 0000000000001000
cr0: 0000000080010010 cr2: 00007fd7fe85bf90
cr3: 0000000187d0c000 cr4: 0000000000000020
[...]
What happens is that VCPU state right after offlinig:
CR0: 0x80050033 EFER: 0xd01 CR4: 0x7e0
-> long mode with CR3 pointing to longmode page tables
and when VCPU gets INIT/SIPI following transition happens
CR0: 0 -> 0x60000010 EFER: 0x0 CR4: 0x7e0
-> paging disabled with stale CR3
However SVM under the hood puts VCPU in Paged Real Mode*
which effectively translates CR0 0x60000010 -> 80010010 after
svm_vcpu_reset()
-> init_vmcb()
-> kvm_set_cr0()
-> svm_set_cr0()
but from kvm_set_cr0() perspective CR0: 0 -> 0x60000010
only caching bits are changed and
commit d81135a57aa6
("KVM: x86: do not reset mmu if CR0.CD and CR0.NW are changed")'
regressed svm_vcpu_reset() which relied on MMU being reset.
As result VMRUN after svm_vcpu_reset() tries to run
VCPU in Paged Real Mode with stale MMU context (longmode page tables),
which causes some AMD CPUs** to bail out with VMEXIT_INVALID.
Fix issue by unconditionally resetting MMU context
at init_vmcb() time.
* AMD64 Architecture Programmer’s Manual,
Volume 2: System Programming, rev: 3.25
15.19 Paged Real Mode
** Opteron 1216
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Fixes: d81135a57aa6
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/svm.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index fdb8cb63a6c0..89173af53c84 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -1264,6 +1264,7 @@ static void init_vmcb(struct vcpu_svm *svm, bool init_event) * It also updates the guest-visible cr0 value. */ (void)kvm_set_cr0(&svm->vcpu, X86_CR0_NW | X86_CR0_CD | X86_CR0_ET); + kvm_mmu_reset_context(&svm->vcpu); save->cr4 = X86_CR4_PAE; /* rdx = ?? */ |