[PATCH AUTOSEL for 4.4 01/35] KVM: x86: emulator: Return to user-mode on L1 CPL=0 emulation failure

Sasha Levin
2018-01-24T04:32:08Z

From: Liran Alon <liran.alon@oracle.com>

[ Upstream commit 1f4dcb3b213235e642088709a1c54964d23365e9 ]

On this case, handle_emulation_failure() fills kvm_run with
internal-error information which it expects to be delivered
to user-mode for further processing.
However, the code reports a wrong return-value which makes KVM to never
return to user-mode on this scenario.

Fixes: 6d77dbfc88e3 ("KVM: inject #UD if instruction emulation fails and exit to
userspace")

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@microsoft.com>
---
arch/x86/kvm/x86.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index f973cfa8ff4f..3900d34980de 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5153,7 +5153,7 @@ static int handle_emulation_failure(struct kvm_vcpu *vcpu)
vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;
vcpu->run->internal.ndata = 0;
- r = EMULATE_FAIL;
+ r = EMULATE_USER_EXIT;
}
kvm_queue_exception(vcpu, UD_VECTOR);

--
2.11.0