KVM: fix push of wrong eip when doing softint

When doing a soft int, we need to bump eip before pushing it to
the stack.  Otherwise we'll do the int a second time.

[apw@canonical.com: merged eip update as per Jan's recommendation.]
Signed-off-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/x86/kvm/vmx.c

@@ -1063,7 +1063,10 @@ static void vmx_queue_exception(struct kvm_vcpu *vcpu, unsigned nr,
 	}
 
 	if (vmx->rmode.vm86_active) {
-		if (kvm_inject_realmode_interrupt(vcpu, nr) != EMULATE_DONE)
+		int inc_eip = 0;
+		if (kvm_exception_is_soft(nr))
+			inc_eip = vcpu->arch.event_exit_inst_len;
+		if (kvm_inject_realmode_interrupt(vcpu, nr, inc_eip) != EMULATE_DONE)
 			kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
 		return;
 	}
@@ -2942,7 +2945,10 @@ static void vmx_inject_irq(struct kvm_vcpu *vcpu)
 
 	++vcpu->stat.irq_injections;
 	if (vmx->rmode.vm86_active) {
-		if (kvm_inject_realmode_interrupt(vcpu, irq) != EMULATE_DONE)
+		int inc_eip = 0;
+		if (vcpu->arch.interrupt.soft)
+			inc_eip = vcpu->arch.event_exit_inst_len;
+		if (kvm_inject_realmode_interrupt(vcpu, irq, inc_eip) != EMULATE_DONE)
 			kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
 		return;
 	}
@@ -2977,7 +2983,7 @@ static void vmx_inject_nmi(struct kvm_vcpu *vcpu)
 	++vcpu->stat.nmi_injections;
 	vmx->nmi_known_unmasked = false;
 	if (vmx->rmode.vm86_active) {
-		if (kvm_inject_realmode_interrupt(vcpu, NMI_VECTOR) != EMULATE_DONE)
+		if (kvm_inject_realmode_interrupt(vcpu, NMI_VECTOR, 0) != EMULATE_DONE)
 			kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
 		return;
 	}

arch/x86/kvm/x86.c

@@ -4423,7 +4423,7 @@ static void init_emulate_ctxt(struct kvm_vcpu *vcpu)
 	vcpu->arch.emulate_regs_need_sync_from_vcpu = false;
 }
 
-int kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq)
+int kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq, int inc_eip)
 {
 	struct decode_cache *c = &vcpu->arch.emulate_ctxt.decode;
 	int ret;
@@ -4432,7 +4432,8 @@ int kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq)
 
 	vcpu->arch.emulate_ctxt.decode.op_bytes = 2;
 	vcpu->arch.emulate_ctxt.decode.ad_bytes = 2;
-	vcpu->arch.emulate_ctxt.decode.eip = vcpu->arch.emulate_ctxt.eip;
+	vcpu->arch.emulate_ctxt.decode.eip = vcpu->arch.emulate_ctxt.eip +
+								 inc_eip;
 	ret = emulate_int_real(&vcpu->arch.emulate_ctxt, &emulate_ops, irq);
 
 	if (ret != X86EMUL_CONTINUE)

arch/x86/kvm/x86.h

@@ -77,7 +77,7 @@ static inline u32 bit(int bitno)
 
 void kvm_before_handle_nmi(struct kvm_vcpu *vcpu);
 void kvm_after_handle_nmi(struct kvm_vcpu *vcpu);
-int kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq);
+int kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq, int inc_eip);
 
 void kvm_write_tsc(struct kvm_vcpu *vcpu, u64 data);