KVM: x86 emulator: don't update vcpu state if instruction is restarted

No need to update vcpu state since instruction is in the middle of the
emulation.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 33deb75..3cbe803 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4057,32 +4057,27 @@ restart:
                return handle_emulation_failure(vcpu);
        }
 
-       toggle_interruptibility(vcpu, vcpu->arch.emulate_ctxt.interruptibility);
-       kvm_x86_ops->set_rflags(vcpu, vcpu->arch.emulate_ctxt.eflags);
-       memcpy(vcpu->arch.regs, c->regs, sizeof c->regs);
-       kvm_rip_write(vcpu, vcpu->arch.emulate_ctxt.eip);
+       r = EMULATE_DONE;
 
-       if (vcpu->arch.emulate_ctxt.exception >= 0) {
+       if (vcpu->arch.emulate_ctxt.exception >= 0)
                inject_emulated_exception(vcpu);
-               return EMULATE_DONE;
-       }
-
-       if (vcpu->arch.pio.count) {
+       else if (vcpu->arch.pio.count) {
                if (!vcpu->arch.pio.in)
                        vcpu->arch.pio.count = 0;
-               return EMULATE_DO_MMIO;
-       }
-
-       if (vcpu->mmio_needed) {
+               r = EMULATE_DO_MMIO;
+       } else if (vcpu->mmio_needed) {
                if (vcpu->mmio_is_write)
                        vcpu->mmio_needed = 0;
-               return EMULATE_DO_MMIO;
-       }
-
-       if (vcpu->arch.emulate_ctxt.restart)
+               r = EMULATE_DO_MMIO;
+       } else if (vcpu->arch.emulate_ctxt.restart)
                goto restart;
 
-       return EMULATE_DONE;
+       toggle_interruptibility(vcpu, vcpu->arch.emulate_ctxt.interruptibility);
+       kvm_x86_ops->set_rflags(vcpu, vcpu->arch.emulate_ctxt.eflags);
+       memcpy(vcpu->arch.regs, c->regs, sizeof c->regs);
+       kvm_rip_write(vcpu, vcpu->arch.emulate_ctxt.eip);
+
+       return r;
 }
 EXPORT_SYMBOL_GPL(emulate_instruction);