KVM: nSVM: Unify RIP and PMU handling calls when emulating VMRUN

The code paths for advancing RIP and retiring the instruction for RIP
are very similar whether or not caching vmcb12 succeeds. The only
difference is handling mapping failures (i.e. EFAULT).

Pull the mapping failure handling out and unify the calls to
svm_skip_emulated_instruction() and kvm_pmu_instruction_retired(), but
return immediately after if copying and caching vmcb12 failed. A nice
side effect of this is that the FIXME comment is now above the only code
path calling svm_skip_emulated_instruction().

Signed-off-by: Yosry Ahmed <yosry@kernel.org>
Link: https://patch.msgid.link/20260527234711.4175166-4-yosry@kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 6e26c8e1b7717ca1298453e9707b117f53d40779..2ef31efd4c9d106618add5a68a592a783fa8f892 100644 (file)
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -1136,20 +1136,13 @@ int nested_svm_vmrun(struct kvm_vcpu *vcpu)
        }
 
        ret = nested_svm_copy_vmcb12_to_cache(vcpu, vmcb12_gpa);
-       if (ret) {
-               if (ret == -EFAULT)
-                       return kvm_handle_memory_failure(vcpu, X86EMUL_IO_NEEDED, NULL);
-
-               /* Advance RIP past VMRUN as part of the nested #VMEXIT. */
-               if (!svm_skip_emulated_instruction(vcpu))
-                       return 0;
-
-               kvm_pmu_instruction_retired(vcpu);
-               return 1;
-       }
+       if (ret == -EFAULT)
+               return kvm_handle_memory_failure(vcpu, X86EMUL_IO_NEEDED, NULL);
 
        /*
-        * At this point, VMRUN is guaranteed to not fault; advance RIP.
+        * At this point, VMRUN is guaranteed to not fault; advance RIP. If
+        * caching vmcb12 failed for other reasons, return immediately afterward
+        * as a nested #VMEXIT was already set up.
         *
         * FIXME: If TF is set on VMRUN should inject a #DB (or handle guest
         * debugging) right after #VMEXIT, right now it's just ignored.
@@ -1159,6 +1152,9 @@ int nested_svm_vmrun(struct kvm_vcpu *vcpu)
 
        kvm_pmu_instruction_retired(vcpu);
 
+       if (ret)
+               return 1;
+
        /*
         * Since vmcb01 is not in use, we can use it to store some of the L1
         * state.