Re: [PATCH 6/9] KVM: SVM: WARN if KVM attempts emulation on #UD or #GP for SEV guests

[Paolo Bonzini]

On 1/20/22 18:04, Sean Christopherson wrote:
> > > +	WARN_ON_ONCE(emul_type & (EMULTYPE_TRAP_UD | EMULTYPE_VMWARE_GP));
> > What about EMULTYPE_TRAP_UD_FORCED?
> Hmm, yeah, it's worth adding, there's no additional cost.  I was thinking it was
> a modifier to EMULTYPE_TRAP_UD, but it's a replacement specifically to bypass
> the EmulateOnUD check (which I should have remembered since I added the type...).

Added on top:

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index d5fe71862bcb..85bbfba1fa07 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4269,7 +4269,9 @@ static bool svm_can_emulate_instruction(struct kvm_vcpu *vcpu, int emul_type,
 		return true;
 
 	/* #UD and #GP should never be intercepted for SEV guests. */
-	WARN_ON_ONCE(emul_type & (EMULTYPE_TRAP_UD | EMULTYPE_VMWARE_GP));
+	WARN_ON_ONCE(emul_type & (EMULTYPE_TRAP_UD |
+				  EMULTYPE_TRAP_UD_FORCED |
+				  EMULTYPE_VMWARE_GP));
 
 	/*
 	 * Emulation is impossible for SEV-ES guests as KVM doesn't have access


Paolo