From: Vitaly Kuznetsov <vkuznets@redhat.com>
Date: Tue, 13 Aug 2019 13:53:35 +0000 (+0200)
Subject: x86: KVM: svm: eliminate hardcoded RIP advancement from vmrun_interception()
X-Git-Tag: v5.4-rc1~138^2~31
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=c8e16b78c6142afea428dc316c900644951cf7f3;p=platform%2Fkernel%2Flinux-rpi.git

x86: KVM: svm: eliminate hardcoded RIP advancement from vmrun_interception()

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.christopherson@intel.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 248ea13..6708bb8 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -3585,7 +3585,7 @@ 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;
@@ -3594,13 +3594,16 @@ 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)) {
@@ -3611,7 +3614,7 @@ 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,
@@ -3664,7 +3667,7 @@ 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)
@@ -3740,9 +3743,6 @@ 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);
 }