KVM: X86: Propagate fetch faults

KVM currently ignores fetch faults in the instruction
emulator. With nested-npt we could have such faults. This
patch adds the code to handle these.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/x86/kvm/emulate.c

@@ -1198,6 +1198,9 @@ static int emulate_popf(struct x86_emulate_ctxt *ctxt,
 	*(unsigned long *)dest =
 		(ctxt->eflags & ~change_mask) | (val & change_mask);
 
+	if (rc == X86EMUL_PROPAGATE_FAULT)
+		emulate_pf(ctxt);
+
 	return rc;
 }
 

arch/x86/kvm/x86.c

@@ -4247,6 +4247,9 @@ int emulate_instruction(struct kvm_vcpu *vcpu,
 		vcpu->arch.emulate_ctxt.perm_ok = false;
 
 		r = x86_decode_insn(&vcpu->arch.emulate_ctxt);
+		if (r == X86EMUL_PROPAGATE_FAULT)
+			goto done;
+
 		trace_kvm_emulate_insn_start(vcpu);
 
 		/* Only allow emulation of specific instructions on #UD
@@ -4305,6 +4308,7 @@ restart:
 		return handle_emulation_failure(vcpu);
 	}
 
+done:
 	if (vcpu->arch.emulate_ctxt.exception >= 0) {
 		inject_emulated_exception(vcpu);
 		r = EMULATE_DONE;