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From: Sean Christopherson <seanjc@google.com>
To: Vitaly Kuznetsov <vkuznets@redhat.com>,
	Sean Christopherson <seanjc@google.com>,
	 Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	 Stefan Teodorescu <fane@google.com>
Subject: [PATCH 1/2] KVM: x86: Convert WARN_ON(preemptible()) to lockdep assertion
Date: Thu, 22 Oct 2026 14:55:40 -0700	[thread overview]
Message-ID: <20261022215541.631694-2-seanjc@google.com> (raw)
In-Reply-To: <20261022215541.631694-1-seanjc@google.com>

Use lockdep_assert_preemption_disabled() in the local APIC code instead of
open-coding a rough equivalent that would likely do more harm than good if
it were to ever fire (the non-ONCE WARN_ON() would likely spam the kernel
log and hang the host).

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/kvm/lapic.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index ecf611845fb1..61bf09badb5a 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -2270,7 +2270,8 @@ bool kvm_lapic_hv_timer_in_use(struct kvm_vcpu *vcpu)
 
 static void cancel_hv_timer(struct kvm_lapic *apic)
 {
-	WARN_ON(preemptible());
+	lockdep_assert_preemption_disabled();
+
 	WARN_ON(!apic->lapic_timer.hv_timer_in_use);
 	kvm_x86_call(cancel_hv_timer)(apic->vcpu);
 	apic->lapic_timer.hv_timer_in_use = false;
@@ -2282,7 +2283,8 @@ static bool start_hv_timer(struct kvm_lapic *apic)
 	struct kvm_vcpu *vcpu = apic->vcpu;
 	bool expired;
 
-	WARN_ON(preemptible());
+	lockdep_assert_preemption_disabled();
+
 	if (!kvm_can_use_hv_timer(vcpu))
 		return false;
 
@@ -2322,7 +2324,8 @@ static void start_sw_timer(struct kvm_lapic *apic)
 {
 	struct kvm_timer *ktimer = &apic->lapic_timer;
 
-	WARN_ON(preemptible());
+	lockdep_assert_preemption_disabled();
+
 	if (apic->lapic_timer.hv_timer_in_use)
 		cancel_hv_timer(apic);
 	if (!apic_lvtt_period(apic) && atomic_read(&ktimer->pending))
-- 
2.56.0.257.gf7497c7d27-goog


  reply	other threads:[~2026-10-22 21:55 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-22 21:55 [PATCH 0/2] KVM: x86: Convert all runtime WARNs to ONCE Sean Christopherson
2026-10-22 21:55 ` Sean Christopherson [this message]
2026-10-22 21:55 ` [PATCH 2/2] KVM: x86: Convert all runtime WARNs to ONCE variants Sean Christopherson

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