[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20240216184153.2714504-7-oliver.upton@linux.dev>
Date: Fri, 16 Feb 2024 18:41:49 +0000
From: Oliver Upton <oliver.upton@...ux.dev>
To: kvmarm@...ts.linux.dev
Cc: kvm@...r.kernel.org,
Marc Zyngier <maz@...nel.org>,
James Morse <james.morse@....com>,
Suzuki K Poulose <suzuki.poulose@....com>,
Zenghui Yu <yuzenghui@...wei.com>,
linux-kernel@...r.kernel.org,
Oliver Upton <oliver.upton@...ux.dev>
Subject: [PATCH v3 06/10] KVM: arm64: vgic: Use atomics to count LPIs
Switch to using atomics for LPI accounting, allowing vgic_irq references
to be dropped in parallel.
Signed-off-by: Oliver Upton <oliver.upton@...ux.dev>
---
arch/arm64/kvm/vgic/vgic-debug.c | 2 +-
arch/arm64/kvm/vgic/vgic-its.c | 4 ++--
arch/arm64/kvm/vgic/vgic.c | 2 +-
include/kvm/arm_vgic.h | 4 ++--
4 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/arch/arm64/kvm/vgic/vgic-debug.c b/arch/arm64/kvm/vgic/vgic-debug.c
index 85606a531dc3..389025ce7749 100644
--- a/arch/arm64/kvm/vgic/vgic-debug.c
+++ b/arch/arm64/kvm/vgic/vgic-debug.c
@@ -149,7 +149,7 @@ static void print_dist_state(struct seq_file *s, struct vgic_dist *dist)
seq_printf(s, "vgic_model:\t%s\n", v3 ? "GICv3" : "GICv2");
seq_printf(s, "nr_spis:\t%d\n", dist->nr_spis);
if (v3)
- seq_printf(s, "nr_lpis:\t%d\n", dist->lpi_list_count);
+ seq_printf(s, "nr_lpis:\t%d\n", atomic_read(&dist->lpi_count));
seq_printf(s, "enabled:\t%d\n", dist->enabled);
seq_printf(s, "\n");
diff --git a/arch/arm64/kvm/vgic/vgic-its.c b/arch/arm64/kvm/vgic/vgic-its.c
index 0d1cfc776f47..27a7451ad8b9 100644
--- a/arch/arm64/kvm/vgic/vgic-its.c
+++ b/arch/arm64/kvm/vgic/vgic-its.c
@@ -96,7 +96,7 @@ static struct vgic_irq *vgic_add_lpi(struct kvm *kvm, u32 intid,
goto out_unlock;
}
- dist->lpi_list_count++;
+ atomic_inc(&dist->lpi_count);
out_unlock:
raw_spin_unlock_irqrestore(&dist->lpi_list_lock, flags);
@@ -344,7 +344,7 @@ int vgic_copy_lpi_list(struct kvm *kvm, struct kvm_vcpu *vcpu, u32 **intid_ptr)
* command). If coming from another path (such as enabling LPIs),
* we must be careful not to overrun the array.
*/
- irq_count = READ_ONCE(dist->lpi_list_count);
+ irq_count = atomic_read(&dist->lpi_count);
intids = kmalloc_array(irq_count, sizeof(intids[0]), GFP_KERNEL_ACCOUNT);
if (!intids)
return -ENOMEM;
diff --git a/arch/arm64/kvm/vgic/vgic.c b/arch/arm64/kvm/vgic/vgic.c
index e58ce68e325c..5988d162b765 100644
--- a/arch/arm64/kvm/vgic/vgic.c
+++ b/arch/arm64/kvm/vgic/vgic.c
@@ -122,7 +122,7 @@ void __vgic_put_lpi_locked(struct kvm *kvm, struct vgic_irq *irq)
return;
xa_erase(&dist->lpi_xa, irq->intid);
- dist->lpi_list_count--;
+ atomic_dec(&dist->lpi_count);
kfree(irq);
}
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index aeff363e3ba6..71e9d719533b 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -273,10 +273,10 @@ struct vgic_dist {
*/
u64 propbaser;
- /* Protects the lpi_list and the count value below. */
+ /* Protects the lpi_list. */
raw_spinlock_t lpi_list_lock;
struct xarray lpi_xa;
- int lpi_list_count;
+ atomic_t lpi_count;
/* LPI translation cache */
struct list_head lpi_translation_cache;
--
2.44.0.rc0.258.g7320e95886-goog
Powered by blists - more mailing lists