Commit 775fde86 authored Apr 04, 2011 by Joerg Roedel Committed by Avi Kivity May 11, 2011

KVM: x86 emulator: Don't write-back cpu-state on X86EMUL_INTERCEPTED



This patch prevents the changed CPU state to be written back
when the emulator detected that the instruction was
intercepted by the guest.

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

parent 3c6e276f

arch/x86/include/asm/kvm_emulate.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -331,6 +331,7 @@ int x86_decode_insn(struct x86_emulate_ctxt ctxt, void insn, int insn_len);
		#define EMULATION_FAILED -1
		#define EMULATION_OK 0
		#define EMULATION_RESTART 1
		#define EMULATION_INTERCEPTED 2
		int x86_emulate_insn(struct x86_emulate_ctxt *ctxt);
		int emulator_task_switch(struct x86_emulate_ctxt *ctxt,
		u16 tss_selector, int reason,

arch/x86/kvm/emulate.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -3592,6 +3592,9 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
		done:
		if (rc == X86EMUL_PROPAGATE_FAULT)
		ctxt->have_exception = true;
		if (rc == X86EMUL_INTERCEPTED)
		return EMULATION_INTERCEPTED;

		return (rc == X86EMUL_UNHANDLEABLE) ? EMULATION_FAILED : EMULATION_OK;

		twobyte_insn:

arch/x86/kvm/x86.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -4516,6 +4516,9 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu,
		restart:
		r = x86_emulate_insn(&vcpu->arch.emulate_ctxt);

		if (r == EMULATION_INTERCEPTED)
		return EMULATE_DONE;

		if (r == EMULATION_FAILED) {
		if (reexecute_instruction(vcpu, cr2))
		return EMULATE_DONE;