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Message-ID: <20251030194130.307900-1-mlevitsk@redhat.com>
Date: Thu, 30 Oct 2025 15:41:30 -0400
From: Maxim Levitsky <mlevitsk@...hat.com>
To: kvm@...r.kernel.org
Cc: Dave Hansen <dave.hansen@...ux.intel.com>,
Ingo Molnar <mingo@...hat.com>,
Borislav Petkov <bp@...en8.de>,
Thomas Gleixner <tglx@...utronix.de>,
Paolo Bonzini <pbonzini@...hat.com>,
Sean Christopherson <seanjc@...gle.com>,
linux-kernel@...r.kernel.org,
"H. Peter Anvin" <hpa@...or.com>,
x86@...nel.org,
Maxim Levitsky <mlevitsk@...hat.com>
Subject: [PATCH] KVM: SVM: switch to raw spinlock for svm->ir_list_lock
svm->ir_list_lock can be taken during __avic_vcpu_put which can be called
from schedule() via kvm_sched_out.
Therefore use a raw spinlock instead.
This fixes the following lockdep warning:
[ 728.022965] =============================
[ 728.027438] [ BUG: Invalid wait context ]
[ 728.031911] 6.12.0-146.1640_2124176644.el10.x86_64+debug #1 Not tainted
[ 728.039294] -----------------------------
[ 728.043765] qemu-kvm/38299 is trying to lock:
[ 728.048624] ff11000239725600 (&svm->ir_list_lock){....}-{3:3}, at: __avic_vcpu_put+0xfd/0x300 [kvm_amd]
[ 728.059135] other info that might help us debug this:
[ 728.064768] context-{5:5}
[ 728.067688] 2 locks held by qemu-kvm/38299:
[ 728.072352] #0: ff11000239723ba8 (&vcpu->mutex){+.+.}-{4:4}, at: kvm_vcpu_ioctl+0x240/0xe00 [kvm]
[ 728.082425] #1: ff11000b906056d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2e/0x130
[ 728.092540] stack backtrace:
[ 728.095758] CPU: 1 UID: 0 PID: 38299 Comm: qemu-kvm Kdump: loaded Not tainted 6.12.0-146.1640_2124176644.el10.x86_64+debug #1 PREEMPT(voluntary)
[ 728.095763] Hardware name: AMD Corporation QUARTZ/QUARTZ, BIOS RQZ100AB 09/14/2023
[ 728.095766] Call Trace:
[ 728.095769] <TASK>
[ 728.095775] dump_stack_lvl+0x6f/0xb0
[ 728.095782] __lock_acquire+0x921/0xb80
[ 728.095787] ? mark_held_locks+0x40/0x70
[ 728.095793] lock_acquire.part.0+0xbe/0x270
[ 728.095797] ? __avic_vcpu_put+0xfd/0x300 [kvm_amd]
[ 728.095811] ? srso_alias_return_thunk+0x5/0xfbef5
[ 728.095815] ? rcu_is_watching+0x15/0xb0
[ 728.095818] ? srso_alias_return_thunk+0x5/0xfbef5
[ 728.095821] ? lock_acquire+0x120/0x170
[ 728.095824] ? __avic_vcpu_put+0xfd/0x300 [kvm_amd]
[ 728.095836] _raw_spin_lock_irqsave+0x46/0x90
[ 728.095840] ? __avic_vcpu_put+0xfd/0x300 [kvm_amd]
[ 728.095850] __avic_vcpu_put+0xfd/0x300 [kvm_amd]
[ 728.095866] svm_vcpu_put+0xfa/0x130 [kvm_amd]
[ 728.095877] kvm_arch_vcpu_put+0x48c/0x790 [kvm]
[ 728.095944] kvm_sched_out+0x161/0x1c0 [kvm]
[ 728.095994] prepare_task_switch+0x36b/0xf60
[ 728.095998] ? rcu_is_watching+0x15/0xb0
[ 728.096004] __schedule+0x4f7/0x1890
[ 728.096010] ? __pfx___schedule+0x10/0x10
[ 728.096012] ? srso_alias_return_thunk+0x5/0xfbef5
[ 728.096019] ? __pfx_vcpu_enter_guest.constprop.0+0x10/0x10 [kvm]
[ 728.096067] ? srso_alias_return_thunk+0x5/0xfbef5
[ 728.096069] ? find_held_lock+0x32/0x90
[ 728.096072] ? local_clock_noinstr+0xd/0xe0
[ 728.096080] schedule+0xd4/0x260
[ 728.096083] xfer_to_guest_mode_handle_work+0x54/0xc0
[ 728.096089] vcpu_run+0x69a/0xa70 [kvm]
[ 728.096136] kvm_arch_vcpu_ioctl_run+0xdc0/0x17e0 [kvm]
[ 728.096185] kvm_vcpu_ioctl+0x39f/0xe00 [kvm]
Signed-off-by: Maxim Levitsky <mlevitsk@...hat.com>
---
arch/x86/kvm/svm/avic.c | 16 ++++++++--------
arch/x86/kvm/svm/svm.h | 2 +-
2 files changed, 9 insertions(+), 9 deletions(-)
diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
index f286b5706d7c..2814e7e24e89 100644
--- a/arch/x86/kvm/svm/avic.c
+++ b/arch/x86/kvm/svm/avic.c
@@ -788,7 +788,7 @@ int avic_init_vcpu(struct vcpu_svm *svm)
struct kvm_vcpu *vcpu = &svm->vcpu;
INIT_LIST_HEAD(&svm->ir_list);
- spin_lock_init(&svm->ir_list_lock);
+ raw_spin_lock_init(&svm->ir_list_lock);
if (!enable_apicv || !irqchip_in_kernel(vcpu->kvm))
return 0;
@@ -816,9 +816,9 @@ static void svm_ir_list_del(struct kvm_kernel_irqfd *irqfd)
if (!vcpu)
return;
- spin_lock_irqsave(&to_svm(vcpu)->ir_list_lock, flags);
+ raw_spin_lock_irqsave(&to_svm(vcpu)->ir_list_lock, flags);
list_del(&irqfd->vcpu_list);
- spin_unlock_irqrestore(&to_svm(vcpu)->ir_list_lock, flags);
+ raw_spin_unlock_irqrestore(&to_svm(vcpu)->ir_list_lock, flags);
}
int avic_pi_update_irte(struct kvm_kernel_irqfd *irqfd, struct kvm *kvm,
@@ -855,7 +855,7 @@ int avic_pi_update_irte(struct kvm_kernel_irqfd *irqfd, struct kvm *kvm,
* list of IRQs being posted to the vCPU, to ensure the IRTE
* isn't programmed with stale pCPU/IsRunning information.
*/
- guard(spinlock_irqsave)(&svm->ir_list_lock);
+ guard(raw_spinlock_irqsave)(&svm->ir_list_lock);
/*
* Update the target pCPU for IOMMU doorbells if the vCPU is
@@ -972,7 +972,7 @@ static void __avic_vcpu_load(struct kvm_vcpu *vcpu, int cpu,
* up-to-date entry information, or that this task will wait until
* svm_ir_list_add() completes to set the new target pCPU.
*/
- spin_lock_irqsave(&svm->ir_list_lock, flags);
+ raw_spin_lock_irqsave(&svm->ir_list_lock, flags);
entry = svm->avic_physical_id_entry;
WARN_ON_ONCE(entry & AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK);
@@ -997,7 +997,7 @@ static void __avic_vcpu_load(struct kvm_vcpu *vcpu, int cpu,
avic_update_iommu_vcpu_affinity(vcpu, h_physical_id, action);
- spin_unlock_irqrestore(&svm->ir_list_lock, flags);
+ raw_spin_unlock_irqrestore(&svm->ir_list_lock, flags);
}
void avic_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
@@ -1035,7 +1035,7 @@ static void __avic_vcpu_put(struct kvm_vcpu *vcpu, enum avic_vcpu_action action)
* or that this task will wait until svm_ir_list_add() completes to
* mark the vCPU as not running.
*/
- spin_lock_irqsave(&svm->ir_list_lock, flags);
+ raw_spin_lock_irqsave(&svm->ir_list_lock, flags);
avic_update_iommu_vcpu_affinity(vcpu, -1, action);
@@ -1059,7 +1059,7 @@ static void __avic_vcpu_put(struct kvm_vcpu *vcpu, enum avic_vcpu_action action)
svm->avic_physical_id_entry = entry;
- spin_unlock_irqrestore(&svm->ir_list_lock, flags);
+ raw_spin_unlock_irqrestore(&svm->ir_list_lock, flags);
}
void avic_vcpu_put(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index e4b04f435b3d..dbd87a87046a 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -329,7 +329,7 @@ struct vcpu_svm {
* back into remapped mode).
*/
struct list_head ir_list;
- spinlock_t ir_list_lock;
+ raw_spinlock_t ir_list_lock;
struct vcpu_sev_es_state sev_es;
--
2.49.0
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