KVM: x86 emulator: advance RIP outside x86 emulator code

Return new RIP as part of instruction emulation result instead of
updating KVM's RIP from x86 emulator code.

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

2 files changed, 6 insertions, 3 deletions

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index d7a18a0f80a2..437f31bcffea 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2496,8 +2496,9 @@ int emulator_task_switch(struct x86_emulate_ctxt *ctxt,
 
         if (rc == X86EMUL_CONTINUE) {
                 memcpy(ctxt->vcpu->arch.regs, c->regs, sizeof c->regs);
-                kvm_rip_write(ctxt->vcpu, c->eip);
                 rc = writeback(ctxt, ops);
+                if (rc == X86EMUL_CONTINUE)
+                        ctxt->eip = c->eip;
         }
 
         return (rc == X86EMUL_UNHANDLEABLE) ? -1 : 0;
@@ -2554,7 +2555,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
                 if (address_mask(c, c->regs[VCPU_REGS_RCX]) == 0) {
                 string_done:
                         ctxt->restart = false;
-                        kvm_rip_write(ctxt->vcpu, c->eip);
+                        ctxt->eip = c->eip;
                         goto done;
                 }
                 /* The second termination condition only applies for REPE
@@ -3032,7 +3033,7 @@ writeback:
         ctxt->decode.mem_read.end = 0;
         /* Commit shadow register state. */
         memcpy(ctxt->vcpu->arch.regs, c->regs, sizeof c->regs);
-        kvm_rip_write(ctxt->vcpu, c->eip);
+        ctxt->eip = c->eip;
         ops->set_rflags(ctxt->vcpu, ctxt->eflags);
 
 done:
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9e5a833f3392..8f45cc712dda 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3941,6 +3941,7 @@ restart:
 
         shadow_mask = vcpu->arch.emulate_ctxt.interruptibility;
         kvm_x86_ops->set_interrupt_shadow(vcpu, shadow_mask);
+        kvm_rip_write(vcpu, vcpu->arch.emulate_ctxt.eip);
 
         if (vcpu->arch.pio.count) {
                 if (!vcpu->arch.pio.in)
@@ -4945,6 +4946,7 @@ int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int reason,
         if (ret)
                 return EMULATE_FAIL;
 
+        kvm_rip_write(vcpu, vcpu->arch.emulate_ctxt.eip);
         kvm_x86_ops->set_rflags(vcpu, vcpu->arch.emulate_ctxt.eflags);
         return EMULATE_DONE;
 }