[PATCH v4 7/7] x86: KVM: svm: eliminate hardcoded RIP advancement from vmrun_interception()

[Vitaly Kuznetsov]

Just like we do with other intercepts, in vmrun_interception() we should be
doing kvm_skip_emulated_instruction() and not just RIP += 3. Also, it is
wrong to increment RIP before nested_svm_vmrun() as it can result in
kvm_inject_gp().

We can't call kvm_skip_emulated_instruction() after nested_svm_vmrun() so
move it inside.

Suggested-by: Sean Christopherson <sean.j.christopher...@intel.com>
Signed-off-by: Vitaly Kuznetsov <vkuzn...@redhat.com>
---
 arch/x86/kvm/svm.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 51c39b608ef7..8473cbea7e8b 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -3588,7 +3588,7 @@ static void enter_svm_guest_mode(struct vcpu_svm *svm, 
u64 vmcb_gpa,
 
 static int nested_svm_vmrun(struct vcpu_svm *svm)
 {
-       int rc;
+       int ret;
        struct vmcb *nested_vmcb;
        struct vmcb *hsave = svm->nested.hsave;
        struct vmcb *vmcb = svm->vmcb;
@@ -3597,13 +3597,16 @@ static int nested_svm_vmrun(struct vcpu_svm *svm)
 
        vmcb_gpa = svm->vmcb->save.rax;
 
-       rc = kvm_vcpu_map(&svm->vcpu, gpa_to_gfn(vmcb_gpa), &map);
-       if (rc) {
-               if (rc == -EINVAL)
-                       kvm_inject_gp(&svm->vcpu, 0);
+       ret = kvm_vcpu_map(&svm->vcpu, gpa_to_gfn(vmcb_gpa), &map);
+       if (ret == EINVAL) {
+               kvm_inject_gp(&svm->vcpu, 0);
                return 1;
+       } else if (ret) {
+               return kvm_skip_emulated_instruction(&svm->vcpu);
        }
 
+       ret = kvm_skip_emulated_instruction(&svm->vcpu);
+
        nested_vmcb = map.hva;
 
        if (!nested_vmcb_checks(nested_vmcb)) {
@@ -3614,7 +3617,7 @@ static int nested_svm_vmrun(struct vcpu_svm *svm)
 
                kvm_vcpu_unmap(&svm->vcpu, &map, true);
 
-               return 1;
+               return ret;
        }
 
        trace_kvm_nested_vmrun(svm->vmcb->save.rip, vmcb_gpa,
@@ -3667,7 +3670,7 @@ static int nested_svm_vmrun(struct vcpu_svm *svm)
                nested_svm_vmexit(svm);
        }
 
-       return 1;
+       return ret;
 }
 
 static void nested_svm_vmloadsave(struct vmcb *from_vmcb, struct vmcb *to_vmcb)
@@ -3743,9 +3746,6 @@ static int vmrun_interception(struct vcpu_svm *svm)
        if (nested_svm_check_permissions(svm))
                return 1;
 
-       /* Save rip after vmrun instruction */
-       kvm_rip_write(&svm->vcpu, kvm_rip_read(&svm->vcpu) + 3);
-
        return nested_svm_vmrun(svm);
 }
 
-- 
2.20.1