[PATCH 1/2] KVM: x86 emulator: don't update vcpu state if instruction is restarted.

Gleb Natapov
2010-07-29T12:11:54Z

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

Signed-off-by: Gleb Natapov <gleb@redhat.com>
---
arch/x86/kvm/x86.c | 31 +++++++++++++------------------
1 files changed, 13 insertions(+), 18 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 76fbc32..7e5f075 100644
--- 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);

--
1.7.1