linux-kernel - [PATCH v3 2/6] KVM: SVM: Update "APICv in x2APIC without x2AVIC" in avic.c, not svm.c

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Message-ID: <20250919002136.1349663-3-seanjc@google.com>
Date: Thu, 18 Sep 2025 17:21:32 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Naveen N Rao <naveen@...nel.org>
Subject: [PATCH v3 2/6] KVM: SVM: Update "APICv in x2APIC without x2AVIC" in
 avic.c, not svm.c

Set the "allow_apicv_in_x2apic_without_x2apic_virtualization" flag as part
of avic_hardware_setup() instead of handling in svm_hardware_setup(), and
make x2avic_enabled local to avic.c (setting the flag was the only use in
svm.c).

Opportunistically tag avic_hardware_setup() with __init to make it clear
that nothing untoward is happening with svm_x86_ops.

No functional change intended (aside from the side effects of tagging
avic_hardware_setup() with __init).

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/svm/avic.c | 6 ++++--
 arch/x86/kvm/svm/svm.c  | 4 +---
 arch/x86/kvm/svm/svm.h  | 3 +--
 3 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
index 478a18208a76..683411442476 100644
--- a/arch/x86/kvm/svm/avic.c
+++ b/arch/x86/kvm/svm/avic.c
@@ -77,7 +77,7 @@ static DEFINE_HASHTABLE(svm_vm_data_hash, SVM_VM_DATA_HASH_BITS);
 static u32 next_vm_id = 0;
 static bool next_vm_id_wrapped = 0;
 static DEFINE_SPINLOCK(svm_vm_data_hash_lock);
-bool x2avic_enabled;
+static bool x2avic_enabled;
 
 
 static void avic_set_x2apic_msr_interception(struct vcpu_svm *svm,
@@ -1147,7 +1147,7 @@ void avic_vcpu_unblocking(struct kvm_vcpu *vcpu)
  * - Hypervisor can support both xAVIC and x2AVIC in the same guest.
  * - The mode can be switched at run-time.
  */
-bool avic_hardware_setup(void)
+bool __init avic_hardware_setup(struct kvm_x86_ops *svm_ops)
 {
 	if (!npt_enabled)
 		return false;
@@ -1182,6 +1182,8 @@ bool avic_hardware_setup(void)
 	x2avic_enabled = boot_cpu_has(X86_FEATURE_X2AVIC);
 	if (x2avic_enabled)
 		pr_info("x2AVIC enabled\n");
+	else
+		svm_ops->allow_apicv_in_x2apic_without_x2apic_virtualization = true;
 
 	/*
 	 * Disable IPI virtualization for AMD Family 17h CPUs (Zen1 and Zen2)
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 3bcb88b2e617..d4643dce7c91 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -5354,15 +5354,13 @@ static __init int svm_hardware_setup(void)
 			goto err;
 	}
 
-	enable_apicv = avic = avic && avic_hardware_setup();
+	enable_apicv = avic = avic && avic_hardware_setup(&svm_x86_ops);
 
 	if (!enable_apicv) {
 		enable_ipiv = false;
 		svm_x86_ops.vcpu_blocking = NULL;
 		svm_x86_ops.vcpu_unblocking = NULL;
 		svm_x86_ops.vcpu_get_apicv_inhibit_reasons = NULL;
-	} else if (!x2avic_enabled) {
-		svm_x86_ops.allow_apicv_in_x2apic_without_x2apic_virtualization = true;
 	}
 
 	if (vls) {
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 1e612bbfd36d..811513c8b566 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -48,7 +48,6 @@ extern bool npt_enabled;
 extern int nrips;
 extern int vgif;
 extern bool intercept_smi;
-extern bool x2avic_enabled;
 extern bool vnmi;
 extern int lbrv;
 
@@ -800,7 +799,7 @@ extern struct kvm_x86_nested_ops svm_nested_ops;
 	BIT(APICV_INHIBIT_REASON_PHYSICAL_ID_TOO_BIG)	\
 )
 
-bool avic_hardware_setup(void);
+bool __init avic_hardware_setup(struct kvm_x86_ops *svm_ops);
 int avic_ga_log_notifier(u32 ga_tag);
 void avic_vm_destroy(struct kvm *kvm);
 int avic_vm_init(struct kvm *kvm);
-- 
2.51.0.470.ga7dc726c21-goog