KVM: Skip pio instruction when it is emulated, not executed

patch 0967b7bf in mainline.

If we defer updating rip until pio instructions are executed, we have a
problem with reset:  a pio reset updates rip, and when the instruction
completes we skip the emulated instruction, pointing rip somewhere completely
unrelated.

Fix by updating rip when we see decode the instruction, not after emulation.
Signed-off-by: Avi Kivity <avi@qumranet.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/kvm/kvm_main.c

@@ -1757,8 +1757,6 @@ static int complete_pio(struct kvm_vcpu *vcpu)
 	io->count -= io->cur_count;
 	io->cur_count = 0;
 
-	if (!io->count)
-		kvm_arch_ops->skip_emulated_instruction(vcpu);
 	return 0;
 }
 
@@ -1804,6 +1802,7 @@ int kvm_setup_pio(struct kvm_vcpu *vcpu, struct kvm_run *run, int in,
 
 	pio_dev = vcpu_find_pio_dev(vcpu, port);
 	if (!string) {
+		kvm_arch_ops->skip_emulated_instruction(vcpu);
 		kvm_arch_ops->cache_regs(vcpu);
 		memcpy(vcpu->pio_data, &vcpu->regs[VCPU_REGS_RAX], 4);
 		kvm_arch_ops->decache_regs(vcpu);
@@ -1850,6 +1849,9 @@ int kvm_setup_pio(struct kvm_vcpu *vcpu, struct kvm_run *run, int in,
 	vcpu->run->io.count = now;
 	vcpu->pio.cur_count = now;
 
+	if (now == count)
+		kvm_arch_ops->skip_emulated_instruction(vcpu);
+
 	for (i = 0; i < nr_pages; ++i) {
 		spin_lock(&vcpu->kvm->lock);
 		page = gva_to_page(vcpu, address + i * PAGE_SIZE);