KVM: x86 emulator: commit rflags as part of registers commit

Make sure that rflags is committed only after successful instruction
emulation.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/x86/include/asm/kvm_emulate.h

@@ -136,6 +136,7 @@ struct x86_emulate_ops {
 	ulong (*get_cr)(int cr, struct kvm_vcpu *vcpu);
 	void (*set_cr)(int cr, ulong val, struct kvm_vcpu *vcpu);
 	int (*cpl)(struct kvm_vcpu *vcpu);
+	void (*set_rflags)(struct kvm_vcpu *vcpu, unsigned long rflags);
 };
 
 /* Type, address-of, and value of an instruction's operand. */

arch/x86/kvm/emulate.c

@@ -2972,6 +2972,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 	/* Commit shadow register state. */
 	memcpy(ctxt->vcpu->arch.regs, c->regs, sizeof c->regs);
 	kvm_rip_write(ctxt->vcpu, c->eip);
+	ops->set_rflags(ctxt->vcpu, ctxt->eflags);
 
 done:
 	return (rc == X86EMUL_UNHANDLEABLE) ? -1 : 0;

arch/x86/kvm/x86.c

@@ -3649,6 +3649,11 @@ static void emulator_set_segment_selector(u16 sel, int seg,
 	kvm_set_segment(vcpu, &kvm_seg, seg);
 }
 
+static void emulator_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags)
+{
+	kvm_x86_ops->set_rflags(vcpu, rflags);
+}
+
 static struct x86_emulate_ops emulate_ops = {
 	.read_std            = kvm_read_guest_virt_system,
 	.write_std           = kvm_write_guest_virt_system,
@@ -3666,6 +3671,7 @@ static struct x86_emulate_ops emulate_ops = {
 	.get_cr              = emulator_get_cr,
 	.set_cr              = emulator_set_cr,
 	.cpl                 = emulator_get_cpl,
+	.set_rflags          = emulator_set_rflags,
 };
 
 static void cache_all_regs(struct kvm_vcpu *vcpu)
@@ -3786,8 +3792,6 @@ int emulate_instruction(struct kvm_vcpu *vcpu,
 		return EMULATE_DO_MMIO;
 	}
 
-	kvm_x86_ops->set_rflags(vcpu, vcpu->arch.emulate_ctxt.eflags);
-
 	if (vcpu->mmio_is_write) {
 		vcpu->mmio_needed = 0;
 		return EMULATE_DO_MMIO;