From: Oliver Upton <oliver.upton@linux.dev>
To: kvmarm@lists.linux.dev
Cc: Marc Zyngier <maz@kernel.org>, Joey Gouly <joey.gouly@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Zenghui Yu <yuzenghui@huawei.com>,
Oliver Upton <oliver.upton@linux.dev>
Subject: [PATCH 4/5] KVM: arm64: vgic-v3: Don't require IRQs be disabled for LPI xarray lock
Date: Wed, 3 Sep 2025 23:23:47 -0700 [thread overview]
Message-ID: <20250904062348.223976-5-oliver.upton@linux.dev> (raw)
In-Reply-To: <20250904062348.223976-1-oliver.upton@linux.dev>
Now that the LPI xarray is only read with IRQs disabled, relax the
locking on the xarray to a non-IRQ disabling spinlock.
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---
arch/arm64/kvm/vgic/vgic-init.c | 2 +-
arch/arm64/kvm/vgic/vgic-its.c | 7 +++----
arch/arm64/kvm/vgic/vgic.c | 13 ++++++-------
3 files changed, 10 insertions(+), 12 deletions(-)
diff --git a/arch/arm64/kvm/vgic/vgic-init.c b/arch/arm64/kvm/vgic/vgic-init.c
index 4c777136ea5f..4c3c0d82e476 100644
--- a/arch/arm64/kvm/vgic/vgic-init.c
+++ b/arch/arm64/kvm/vgic/vgic-init.c
@@ -53,7 +53,7 @@ void kvm_vgic_early_init(struct kvm *kvm)
{
struct vgic_dist *dist = &kvm->arch.vgic;
- xa_init_flags(&dist->lpi_xa, XA_FLAGS_LOCK_IRQ);
+ xa_init(&dist->lpi_xa);
}
/* CREATION */
diff --git a/arch/arm64/kvm/vgic/vgic-its.c b/arch/arm64/kvm/vgic/vgic-its.c
index f162206adb48..ce3e3ed3f29f 100644
--- a/arch/arm64/kvm/vgic/vgic-its.c
+++ b/arch/arm64/kvm/vgic/vgic-its.c
@@ -78,7 +78,6 @@ static struct vgic_irq *vgic_add_lpi(struct kvm *kvm, u32 intid,
{
struct vgic_dist *dist = &kvm->arch.vgic;
struct vgic_irq *irq = vgic_get_irq(kvm, intid), *oldirq;
- unsigned long flags;
int ret;
/* In this case there is no put, since we keep the reference. */
@@ -89,7 +88,7 @@ static struct vgic_irq *vgic_add_lpi(struct kvm *kvm, u32 intid,
if (!irq)
return ERR_PTR(-ENOMEM);
- ret = xa_reserve_irq(&dist->lpi_xa, intid, GFP_KERNEL_ACCOUNT);
+ ret = xa_reserve(&dist->lpi_xa, intid, GFP_KERNEL_ACCOUNT);
if (ret) {
kfree(irq);
return ERR_PTR(ret);
@@ -104,7 +103,7 @@ static struct vgic_irq *vgic_add_lpi(struct kvm *kvm, u32 intid,
irq->target_vcpu = vcpu;
irq->group = 1;
- xa_lock_irqsave(&dist->lpi_xa, flags);
+ xa_lock(&dist->lpi_xa);
/*
* There could be a race with another vgic_add_lpi(), so we need to
@@ -126,7 +125,7 @@ static struct vgic_irq *vgic_add_lpi(struct kvm *kvm, u32 intid,
}
out_unlock:
- xa_unlock_irqrestore(&dist->lpi_xa, flags);
+ xa_unlock(&dist->lpi_xa);
if (ret)
return ERR_PTR(ret);
diff --git a/arch/arm64/kvm/vgic/vgic.c b/arch/arm64/kvm/vgic/vgic.c
index 480391a0dcad..a21b482844ce 100644
--- a/arch/arm64/kvm/vgic/vgic.c
+++ b/arch/arm64/kvm/vgic/vgic.c
@@ -28,7 +28,7 @@ struct vgic_global kvm_vgic_global_state __ro_after_init = {
* kvm->arch.config_lock (mutex)
* its->cmd_lock (mutex)
* its->its_lock (mutex)
- * vgic_dist->lpi_xa.xa_lock must be taken with IRQs disabled
+ * vgic_dist->lpi_xa.xa_lock
* vgic_cpu->ap_list_lock must be taken with IRQs disabled
* vgic_irq->irq_lock must be taken with IRQs disabled
*
@@ -141,30 +141,29 @@ static __must_check bool vgic_put_irq_norelease(struct kvm *kvm, struct vgic_irq
void vgic_put_irq(struct kvm *kvm, struct vgic_irq *irq)
{
struct vgic_dist *dist = &kvm->arch.vgic;
- unsigned long flags;
if (!__vgic_put_irq(kvm, irq))
return;
- xa_lock_irqsave(&dist->lpi_xa, flags);
+ xa_lock(&dist->lpi_xa);
vgic_release_lpi_locked(dist, irq);
- xa_unlock_irqrestore(&dist->lpi_xa, flags);
+ xa_unlock(&dist->lpi_xa);
}
static void vgic_release_deleted_lpis(struct kvm *kvm)
{
struct vgic_dist *dist = &kvm->arch.vgic;
- unsigned long flags, intid;
+ unsigned long intid;
struct vgic_irq *irq;
- xa_lock_irqsave(&dist->lpi_xa, flags);
+ xa_lock(&dist->lpi_xa);
xa_for_each(&dist->lpi_xa, intid, irq) {
if (irq->pending_release)
vgic_release_lpi_locked(dist, irq);
}
- xa_unlock_irqrestore(&dist->lpi_xa, flags);
+ xa_unlock(&dist->lpi_xa);
}
void vgic_flush_pending_lpis(struct kvm_vcpu *vcpu)
--
2.39.5
next prev parent reply other threads:[~2025-09-04 7:28 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-04 6:23 [PATCH 0/5] KVM: arm64: vgic-v3: Fix yet another lock ordering turd Oliver Upton
2025-09-04 6:23 ` [PATCH 1/5] KVM: arm64: vgic-v3: Use bare refcount for VGIC LPIs Oliver Upton
2025-09-04 6:23 ` [PATCH 2/5] KVM: arm64: Spin off release helper from vgic_put_irq() Oliver Upton
2025-09-04 6:23 ` [PATCH 3/5] KVM: arm64: vgic-v3: Erase LPIs from xarray outside of raw spinlocks Oliver Upton
2025-09-05 7:44 ` Marc Zyngier
2025-09-05 7:19 ` Oliver Upton
2025-09-04 6:23 ` Oliver Upton [this message]
2025-09-05 8:13 ` [PATCH 4/5] KVM: arm64: vgic-v3: Don't require IRQs be disabled for LPI xarray lock Marc Zyngier
2025-09-05 8:55 ` Oliver Upton
2025-09-04 6:23 ` [PATCH 5/5] KVM: arm64: vgic-v3: Indicate vgic_put_irq() may take " Oliver Upton
2025-09-04 10:25 ` Ben Horgan
2025-09-04 8:19 ` Oliver Upton
2025-09-05 8:29 ` [PATCH 0/5] KVM: arm64: vgic-v3: Fix yet another lock ordering turd Marc Zyngier
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