linux-kernel - [PATCH 16/29] KVM: x86: split "if" in __kvm_set_or_clear_apicv

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Message-ID: <20250401161106.790710-17-pbonzini@redhat.com>
Date: Tue,  1 Apr 2025 18:10:53 +0200
From: Paolo Bonzini <pbonzini@...hat.com>
To: linux-kernel@...r.kernel.org,
	kvm@...r.kernel.org
Cc: roy.hopkins@...e.com,
	seanjc@...gle.com,
	thomas.lendacky@....com,
	ashish.kalra@....com,
	michael.roth@....com,
	jroedel@...e.de,
	nsaenz@...zon.com,
	anelkz@...zon.de,
	James.Bottomley@...senPartnership.com
Subject: [PATCH 16/29] KVM: x86: split "if" in __kvm_set_or_clear_apicv_inhibit

Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/kvm/x86.c | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a527a425c55d..f70d9a572455 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10637,6 +10637,7 @@ void __kvm_set_or_clear_apicv_inhibit(struct kvm *kvm,
 				      enum kvm_apicv_inhibit reason, bool set)
 {
 	unsigned long old, new;
+	bool changed;
 
 	lockdep_assert_held_write(&kvm->arch.apicv_update_lock);
 
@@ -10644,10 +10645,10 @@ void __kvm_set_or_clear_apicv_inhibit(struct kvm *kvm,
 		return;
 
 	old = new = kvm->arch.apicv_inhibit_reasons;
-
 	set_or_clear_apicv_inhibit(&new, reason, set);
+	changed = (!!old != !!new);
 
-	if (!!old != !!new) {
+	if (changed) {
 		/*
 		 * Kick all vCPUs before setting apicv_inhibit_reasons to avoid
 		 * false positives in the sanity check WARN in vcpu_enter_guest().
@@ -10661,16 +10662,16 @@ void __kvm_set_or_clear_apicv_inhibit(struct kvm *kvm,
 		 * servicing the request with a stale apicv_inhibit_reasons.
 		 */
 		kvm_make_all_cpus_request(kvm, KVM_REQ_APICV_UPDATE);
-		kvm->arch.apicv_inhibit_reasons = new;
-		if (new) {
-			unsigned long gfn = gpa_to_gfn(APIC_DEFAULT_PHYS_BASE);
-			int idx = srcu_read_lock(&kvm->srcu);
+	}
 
-			kvm_zap_gfn_range(kvm, gfn, gfn+1);
-			srcu_read_unlock(&kvm->srcu, idx);
-		}
-	} else {
-		kvm->arch.apicv_inhibit_reasons = new;
+	kvm->arch.apicv_inhibit_reasons = new;
+
+	if (changed && set) {
+		unsigned long gfn = gpa_to_gfn(APIC_DEFAULT_PHYS_BASE);
+		int idx = srcu_read_lock(&kvm->srcu);
+
+		kvm_zap_gfn_range(kvm, gfn, gfn+1);
+		srcu_read_unlock(&kvm->srcu, idx);
 	}
 }
 
-- 
2.49.0