[RFC PATCH 3/5] KVM: nSVM: Move updating NextRIP and soft IRQ RIPs into a helper

[Yosry Ahmed <yosry.ahmed@linux.dev>]

Move the logic for updating NextRIP and soft interrupt tracking fields
out of nested_vmcb02_prepare_control() into a helper, in preparation for
re-using the same logic to fixup the RIPs during save/restore.

No functional change intended.

CC: stable@vger.kernel.org
Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
---
 arch/x86/kvm/svm/nested.c | 64 +++++++++++++++++++++++----------------
 arch/x86/kvm/svm/svm.h    |  2 ++
 2 files changed, 40 insertions(+), 26 deletions(-)

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index aec17c80ed73..af7a0113f269 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -741,6 +741,43 @@ static bool is_evtinj_nmi(u32 evtinj)
 	return type == SVM_EVTINJ_TYPE_NMI;
 }
 
+void nested_vmcb02_prepare_rips(struct kvm_vcpu *vcpu, unsigned long csbase,
+				unsigned long rip)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+
+	if (WARN_ON_ONCE(svm->vmcb != svm->nested.vmcb02.ptr))
+		return;
+
+	/*
+	 * NextRIP is consumed on VMRUN as the return address pushed on the
+	 * stack for injected soft exceptions/interrupts.  If nrips is exposed
+	 * to L1, take it verbatim.
+	 *
+	 * If nrips is supported in hardware but not exposed to L1, stuff the
+	 * actual L2 RIP to emulate what a nrips=0 CPU would do (L1 is
+	 * responsible for advancing RIP prior to injecting the event). This is
+	 * only the case for the first L2 run after VMRUN. After that (e.g.
+	 * during save/restore), NextRIP is updated by the CPU and/or KVM, and
+	 * the value of the L2 RIP should not be used.
+	 */
+	if (guest_cpu_cap_has(vcpu, X86_FEATURE_NRIPS) || !svm->nested.nested_run_pending)
+		svm->vmcb->control.next_rip    = svm->nested.ctl.next_rip;
+	else if (boot_cpu_has(X86_FEATURE_NRIPS))
+		svm->vmcb->control.next_rip    = rip;
+
+	if (!is_evtinj_soft(svm->nested.ctl.event_inj))
+		return;
+
+	svm->soft_int_injected = true;
+	svm->soft_int_csbase = csbase;
+	svm->soft_int_old_rip = rip;
+	if (guest_cpu_cap_has(vcpu, X86_FEATURE_NRIPS))
+		svm->soft_int_next_rip = svm->nested.ctl.next_rip;
+	else
+		svm->soft_int_next_rip = rip;
+}
+
 static void nested_vmcb02_prepare_control(struct vcpu_svm *svm,
 					  unsigned long vmcb12_rip,
 					  unsigned long vmcb12_csbase)
@@ -843,33 +880,8 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm,
 	vmcb02->control.event_inj           = svm->nested.ctl.event_inj;
 	vmcb02->control.event_inj_err       = svm->nested.ctl.event_inj_err;
 
-	/*
-	 * NextRIP is consumed on VMRUN as the return address pushed on the
-	 * stack for injected soft exceptions/interrupts.  If nrips is exposed
-	 * to L1, take it verbatim from vmcb12.
-	 *
-	 * If nrips is supported in hardware but not exposed to L1, stuff the
-	 * actual L2 RIP to emulate what a nrips=0 CPU would do (L1 is
-	 * responsible for advancing RIP prior to injecting the event). This is
-	 * only the case for the first L2 run after VMRUN. After that (e.g.
-	 * during save/restore), NextRIP is updated by the CPU and/or KVM, and
-	 * the value of the L2 RIP from vmcb12 should not be used.
-	 */
-	if (guest_cpu_cap_has(vcpu, X86_FEATURE_NRIPS) || !svm->nested.nested_run_pending)
-		vmcb02->control.next_rip    = svm->nested.ctl.next_rip;
-	else if (boot_cpu_has(X86_FEATURE_NRIPS))
-		vmcb02->control.next_rip    = vmcb12_rip;
-
 	svm->nmi_l1_to_l2 = is_evtinj_nmi(vmcb02->control.event_inj);
-	if (is_evtinj_soft(vmcb02->control.event_inj)) {
-		svm->soft_int_injected = true;
-		svm->soft_int_csbase = vmcb12_csbase;
-		svm->soft_int_old_rip = vmcb12_rip;
-		if (guest_cpu_cap_has(vcpu, X86_FEATURE_NRIPS))
-			svm->soft_int_next_rip = svm->nested.ctl.next_rip;
-		else
-			svm->soft_int_next_rip = vmcb12_rip;
-	}
+	nested_vmcb02_prepare_rips(vcpu, vmcb12_csbase, vmcb12_rip);
 
 	/* LBR_CTL_ENABLE_MASK is controlled by svm_update_lbrv() */
 
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index ebd7b36b1ceb..057281dda487 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -809,6 +809,8 @@ void nested_copy_vmcb_save_to_cache(struct vcpu_svm *svm,
 void nested_sync_control_from_vmcb02(struct vcpu_svm *svm);
 void nested_vmcb02_compute_g_pat(struct vcpu_svm *svm);
 void svm_switch_vmcb(struct vcpu_svm *svm, struct kvm_vmcb_info *target_vmcb);
+void nested_vmcb02_prepare_rips(struct kvm_vcpu *vcpu, unsigned long csbase,
+				unsigned long rip);
 
 extern struct kvm_x86_nested_ops svm_nested_ops;
 
-- 
2.53.0.273.g2a3d683680-goog