Commit b4000606 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
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KVM: x86: Add explicit flag for forced emulation on #UD 



Add an explicit emulation type for forced #UD emulation and use it to
detect that KVM should unconditionally inject a #UD instead of falling
into its standard emulation failure handling.

Signed-off-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 42cbf068

arch/x86/include/asm/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -1325,6 +1325,7 @@ enum emulation_result { 
#define EMULTYPE_TRAP_UD	    (1 << 1)

#define EMULTYPE_SKIP		    (1 << 2)

#define EMULTYPE_ALLOW_RETRY	    (1 << 3)

#define EMULTYPE_TRAP_UD_FORCED	    (1 << 4)

#define EMULTYPE_VMWARE_GP	    (1 << 5)

int kvm_emulate_instruction(struct kvm_vcpu *vcpu, int emulation_type);

int kvm_emulate_instruction_from_buffer(struct kvm_vcpu *vcpu,

arch/x86/kvm/x86.c

+3 −2
Original line number Diff line number Diff line
@@ -5449,7 +5449,7 @@ int handle_ud(struct kvm_vcpu *vcpu) 
				sig, sizeof(sig), &e) == 0 &&

	    memcmp(sig, "\xf\xbkvm", sizeof(sig)) == 0) {

		kvm_rip_write(vcpu, kvm_rip_read(vcpu) + sizeof(sig));

		emul_type = 0;

		emul_type = EMULTYPE_TRAP_UD_FORCED;

	}



	er = kvm_emulate_instruction(vcpu, emul_type);
@@ -6629,7 +6629,8 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, 
		trace_kvm_emulate_insn_start(vcpu);

		++vcpu->stat.insn_emulation;

		if (r != EMULATION_OK)  {

			if (emulation_type & EMULTYPE_TRAP_UD)

			if ((emulation_type & EMULTYPE_TRAP_UD) ||

			    (emulation_type & EMULTYPE_TRAP_UD_FORCED))

				return EMULATE_FAIL;

			if (reexecute_instruction(vcpu, cr2, write_fault_to_spt,

						emulation_type))