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KVM: x86: Don't re-execute instruction when not passing CR2 value

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[ Upstream commit 9b8ae63798cb97e785a667ff27e43fa6220cb734 ]

In case of instruction-decode failure or emulation failure,
x86_emulate_instruction() will call reexecute_instruction() which will
attempt to use the cr2 value passed to x86_emulate_instruction().
However, when x86_emulate_instruction() is called from
emulate_instruction(), cr2 is not passed (passed as 0) and therefore
it doesn't make sense to execute reexecute_instruction() logic at all.

Fixes: 51d8b66199e9 ("KVM: cleanup emulate_instruction")

Signed-off-by: Liran Alon <liran.alon@oracle.com>
Reviewed-by: Nikita Leshenko <nikita.leshchenko@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Liran Alon 2017-11-05 16:56:34 +02:00 committed by Greg Kroah-Hartman
parent fbd81f0979
commit df54fc5c28
2 changed files with 3 additions and 2 deletions
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3
arch/x86/include/asm/kvm_host.h
View File

@ -1156,7 +1156,8 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, unsigned long cr2,
static inline int emulate_instruction(struct kvm_vcpu *vcpu,
int emulation_type)
{
return x86_emulate_instruction(vcpu, 0, emulation_type, NULL, 0);
return x86_emulate_instruction(vcpu, 0,
emulation_type | EMULTYPE_NO_REEXECUTE, NULL, 0);
}
void kvm_enable_efer_bits(u64);

2
arch/x86/kvm/vmx.c
View File

@ -6607,7 +6607,7 @@ static int handle_invalid_guest_state(struct kvm_vcpu *vcpu)
if (kvm_test_request(KVM_REQ_EVENT, vcpu))
return 1;
err = emulate_instruction(vcpu, EMULTYPE_NO_REEXECUTE);
err = emulate_instruction(vcpu, 0);
if (err == EMULATE_USER_EXIT) {
++vcpu->stat.mmio_exits;