[PATCH v6 07/31] KVM: nSVM: Refactor writing vmcb12 on nested #VMEXIT as a helper

From: Yosry Ahmed

Date: Tue Feb 24 2026 - 17:36:25 EST


Move mapping vmcb12 and updating it out of nested_svm_vmexit() into a
helper, no functional change intended.

CC: stable@xxxxxxxxxxxxxxx
Co-developed-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Signed-off-by: Yosry Ahmed <yosry@xxxxxxxxxx>
---
arch/x86/kvm/svm/nested.c | 77 ++++++++++++++++++++++-----------------
1 file changed, 44 insertions(+), 33 deletions(-)

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index d11cf4968adbe..6364c52e6e0a8 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -1123,36 +1123,20 @@ void svm_copy_vmloadsave_state(struct vmcb *to_vmcb, struct vmcb *from_vmcb)
to_vmcb->save.sysenter_eip = from_vmcb->save.sysenter_eip;
}

-int nested_svm_vmexit(struct vcpu_svm *svm)
+static int nested_svm_vmexit_update_vmcb12(struct kvm_vcpu *vcpu)
{
- struct kvm_vcpu *vcpu = &svm->vcpu;
- struct vmcb *vmcb01 = svm->vmcb01.ptr;
+ struct vcpu_svm *svm = to_svm(vcpu);
struct vmcb *vmcb02 = svm->nested.vmcb02.ptr;
- struct vmcb *vmcb12;
struct kvm_host_map map;
+ struct vmcb *vmcb12;
int rc;

rc = kvm_vcpu_map(vcpu, gpa_to_gfn(svm->nested.vmcb12_gpa), &map);
- if (rc) {
- if (rc == -EINVAL)
- kvm_inject_gp(vcpu, 0);
- return 1;
- }
+ if (rc)
+ return rc;

vmcb12 = map.hva;

- /* Exit Guest-Mode */
- leave_guest_mode(vcpu);
- svm->nested.vmcb12_gpa = 0;
- WARN_ON_ONCE(svm->nested.nested_run_pending);
-
- kvm_clear_request(KVM_REQ_GET_NESTED_STATE_PAGES, vcpu);
-
- /* in case we halted in L2 */
- kvm_set_mp_state(vcpu, KVM_MP_STATE_RUNNABLE);
-
- /* Give the current vmcb to the guest */
-
vmcb12->save.es = vmcb02->save.es;
vmcb12->save.cs = vmcb02->save.cs;
vmcb12->save.ss = vmcb02->save.ss;
@@ -1189,10 +1173,48 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
if (guest_cpu_cap_has(vcpu, X86_FEATURE_NRIPS))
vmcb12->control.next_rip = vmcb02->control.next_rip;

+ if (nested_vmcb12_has_lbrv(vcpu))
+ svm_copy_lbrs(&vmcb12->save, &vmcb02->save);
+
vmcb12->control.int_ctl = svm->nested.ctl.int_ctl;
vmcb12->control.event_inj = svm->nested.ctl.event_inj;
vmcb12->control.event_inj_err = svm->nested.ctl.event_inj_err;

+ trace_kvm_nested_vmexit_inject(vmcb12->control.exit_code,
+ vmcb12->control.exit_info_1,
+ vmcb12->control.exit_info_2,
+ vmcb12->control.exit_int_info,
+ vmcb12->control.exit_int_info_err,
+ KVM_ISA_SVM);
+
+ kvm_vcpu_unmap(vcpu, &map);
+ return 0;
+}
+
+int nested_svm_vmexit(struct vcpu_svm *svm)
+{
+ struct kvm_vcpu *vcpu = &svm->vcpu;
+ struct vmcb *vmcb01 = svm->vmcb01.ptr;
+ struct vmcb *vmcb02 = svm->nested.vmcb02.ptr;
+ int rc;
+
+ rc = nested_svm_vmexit_update_vmcb12(vcpu);
+ if (rc) {
+ if (rc == -EINVAL)
+ kvm_inject_gp(vcpu, 0);
+ return 1;
+ }
+
+ /* Exit Guest-Mode */
+ leave_guest_mode(vcpu);
+ svm->nested.vmcb12_gpa = 0;
+ WARN_ON_ONCE(svm->nested.nested_run_pending);
+
+ kvm_clear_request(KVM_REQ_GET_NESTED_STATE_PAGES, vcpu);
+
+ /* in case we halted in L2 */
+ kvm_set_mp_state(vcpu, KVM_MP_STATE_RUNNABLE);
+
if (!kvm_pause_in_guest(vcpu->kvm)) {
vmcb01->control.pause_filter_count = vmcb02->control.pause_filter_count;
vmcb_mark_dirty(vmcb01, VMCB_INTERCEPTS);
@@ -1237,9 +1259,7 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
if (!nested_exit_on_intr(svm))
kvm_make_request(KVM_REQ_EVENT, &svm->vcpu);

- if (nested_vmcb12_has_lbrv(vcpu)) {
- svm_copy_lbrs(&vmcb12->save, &vmcb02->save);
- } else {
+ if (!nested_vmcb12_has_lbrv(vcpu)) {
svm_copy_lbrs(&vmcb01->save, &vmcb02->save);
vmcb_mark_dirty(vmcb01, VMCB_LBR);
}
@@ -1295,15 +1315,6 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
svm->vcpu.arch.dr7 = DR7_FIXED_1;
kvm_update_dr7(&svm->vcpu);

- trace_kvm_nested_vmexit_inject(vmcb12->control.exit_code,
- vmcb12->control.exit_info_1,
- vmcb12->control.exit_info_2,
- vmcb12->control.exit_int_info,
- vmcb12->control.exit_int_info_err,
- KVM_ISA_SVM);
-
- kvm_vcpu_unmap(vcpu, &map);
-
nested_svm_transition_tlb_flush(vcpu);

nested_svm_uninit_mmu_context(vcpu);
--
2.53.0.414.gf7e9f6c205-goog