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KVM: x86: Don't attempt VMWare emulation on #GP with non-zero error code

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The VMware backdoor hooks #GP faults on IN{S}, OUT{S}, and RDPMC, none
of which generate a non-zero error code for their #GP.  Re-injecting #GP
instead of attempting emulation on a non-zero error code will allow a
future patch to move #GP injection (for emulation failure) into
kvm_emulate_instruction() without having to plumb in the error code.

Reviewed-and-tested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson
2019-08-27 14:40:30 -07:00
committed by Paolo Bonzini
parent 120c2c4f99
commit a6c6ed1e81
2 changed files with 20 additions and 2 deletions
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12
arch/x86/kvm/vmx/vmx.c
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@@ -4539,12 +4539,22 @@ static int handle_exception_nmi(struct kvm_vcpu *vcpu)
if (!vmx->rmode.vm86_active && is_gp_fault(intr_info)) {
WARN_ON_ONCE(!enable_vmware_backdoor);
/*
* VMware backdoor emulation on #GP interception only handles
* IN{S}, OUT{S}, and RDPMC, none of which generate a non-zero
* error code on #GP.
*/
if (error_code) {
kvm_queue_exception_e(vcpu, GP_VECTOR, error_code);
return 1;
}
er = kvm_emulate_instruction(vcpu,
EMULTYPE_VMWARE | EMULTYPE_NO_UD_ON_FAIL);
if (er == EMULATE_USER_EXIT)
return 0;
else if (er != EMULATE_DONE)
kvm_queue_exception_e(vcpu, GP_VECTOR, error_code);
kvm_queue_exception_e(vcpu, GP_VECTOR, 0);
return 1;
}