From nobody Sat Feb 7 11:39:10 2026 Received: from out-170.mta0.migadu.com (out-170.mta0.migadu.com [91.218.175.170]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8C6953A268 for ; Wed, 21 Feb 2024 05:43:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.170 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708494222; cv=none; b=rkxGO46GGPCPs0qzZGOiNODYZZx22qMabdPc4HwP0dOQ/hbrBWLzelgJAT5vrwUwnV5vEZfUsyRCkNnG7c9iesz3Ortpl1BfpEIatNrco/koE9xibaMFi8FmrvNjoZGGxrfv1nnPtkoFJM3PdI7fQTx6A+1iLrS3OZtjbG8OYJ8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708494222; c=relaxed/simple; bh=huN1PqJtmqytpL0vyqUMZqGEJFXVuxAo91FZdlEJvZw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ANrTd1w0r8MGB6wJu2cg3bWDC+q9JOtrD3YWHLUpRLR0z3pFx2XNV1lsOrqeUIvX1kAFTC/W1pHOmTvCu18afoZXnj+y5ToRTlGN9sDxP+ImaX8uGcgLSNaMfrPlmtrtHWntasxslp7zkZ1QUbiZoNxgGUDar+H67Rj9F2GYWmg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=RK/jSFpK; arc=none smtp.client-ip=91.218.175.170 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="RK/jSFpK" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1708494218; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=7uZnxcLXKLqyPCNevo5l7NpGLhMeejXcsQuYRK9QxO0=; b=RK/jSFpKYJqpDZ2ouKFiZ2I/rdOcsLx5lKza9bI7O/DEvmkWAWOwRt7MBFuz/AgkDXmv1z 1DsW4AldOgmJ72zxrmxbd18hjzeuCR1L2nPxHUhyTOjfZ4E7Nnk5ArYF9wBFEWr2ZBsot/ q64aIxAUJxhWVqMsKVznWHHqpDmDvVA= From: Oliver Upton To: kvmarm@lists.linux.dev Cc: kvm@vger.kernel.org, Marc Zyngier , James Morse , Suzuki K Poulose , Zenghui Yu , linux-kernel@vger.kernel.org, Eric Auger , Oliver Upton Subject: [PATCH v4 10/10] KVM: arm64: vgic: Don't acquire the lpi_list_lock in vgic_put_irq() Date: Wed, 21 Feb 2024 05:42:53 +0000 Message-ID: <20240221054253.3848076-11-oliver.upton@linux.dev> In-Reply-To: <20240221054253.3848076-1-oliver.upton@linux.dev> References: <20240221054253.3848076-1-oliver.upton@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Migadu-Flow: FLOW_OUT Content-Type: text/plain; charset="utf-8" The LPI xarray's xa_lock is sufficient for synchronizing writers when freeing a given LPI. Furthermore, readers can only take a new reference on an IRQ if it was already nonzero. Stop taking the lpi_list_lock unnecessarily and get rid of __vgic_put_lpi_locked(). Signed-off-by: Oliver Upton --- arch/arm64/kvm/vgic/vgic-its.c | 4 ++-- arch/arm64/kvm/vgic/vgic.c | 28 +++++++++------------------- arch/arm64/kvm/vgic/vgic.h | 1 - 3 files changed, 11 insertions(+), 22 deletions(-) diff --git a/arch/arm64/kvm/vgic/vgic-its.c b/arch/arm64/kvm/vgic/vgic-its.c index dad6f0ee7c49..f6025886071c 100644 --- a/arch/arm64/kvm/vgic/vgic-its.c +++ b/arch/arm64/kvm/vgic/vgic-its.c @@ -649,7 +649,7 @@ static void vgic_its_cache_translation(struct kvm *kvm,= struct vgic_its *its, * was in the cache, and increment it on the new interrupt. */ if (cte->irq) - __vgic_put_lpi_locked(kvm, cte->irq); + vgic_put_irq(kvm, cte->irq); =20 /* * The irq refcount is guaranteed to be nonzero while holding the @@ -686,7 +686,7 @@ void vgic_its_invalidate_cache(struct kvm *kvm) if (!cte->irq) break; =20 - __vgic_put_lpi_locked(kvm, cte->irq); + vgic_put_irq(kvm, cte->irq); cte->irq =3D NULL; } =20 diff --git a/arch/arm64/kvm/vgic/vgic.c b/arch/arm64/kvm/vgic/vgic.c index df9e1aa1956c..f963f410788a 100644 --- a/arch/arm64/kvm/vgic/vgic.c +++ b/arch/arm64/kvm/vgic/vgic.c @@ -111,22 +111,6 @@ static void vgic_irq_release(struct kref *ref) { } =20 -/* - * Drop the refcount on the LPI. Must be called with lpi_list_lock held. - */ -void __vgic_put_lpi_locked(struct kvm *kvm, struct vgic_irq *irq) -{ - struct vgic_dist *dist =3D &kvm->arch.vgic; - - if (!kref_put(&irq->refcount, vgic_irq_release)) - return; - - xa_erase(&dist->lpi_xa, irq->intid); - atomic_dec(&dist->lpi_count); - - kfree_rcu(irq, rcu); -} - void vgic_put_irq(struct kvm *kvm, struct vgic_irq *irq) { struct vgic_dist *dist =3D &kvm->arch.vgic; @@ -135,9 +119,15 @@ void vgic_put_irq(struct kvm *kvm, struct vgic_irq *ir= q) if (irq->intid < VGIC_MIN_LPI) return; =20 - raw_spin_lock_irqsave(&dist->lpi_list_lock, flags); - __vgic_put_lpi_locked(kvm, irq); - raw_spin_unlock_irqrestore(&dist->lpi_list_lock, flags); + if (!kref_put(&irq->refcount, vgic_irq_release)) + return; + + xa_lock_irqsave(&dist->lpi_xa, flags); + __xa_erase(&dist->lpi_xa, irq->intid); + xa_unlock_irqrestore(&dist->lpi_xa, flags); + + atomic_dec(&dist->lpi_count); + kfree_rcu(irq, rcu); } =20 void vgic_flush_pending_lpis(struct kvm_vcpu *vcpu) diff --git a/arch/arm64/kvm/vgic/vgic.h b/arch/arm64/kvm/vgic/vgic.h index f874b9932c5a..0c2b82de8fa3 100644 --- a/arch/arm64/kvm/vgic/vgic.h +++ b/arch/arm64/kvm/vgic/vgic.h @@ -180,7 +180,6 @@ vgic_get_mmio_region(struct kvm_vcpu *vcpu, struct vgic= _io_device *iodev, gpa_t addr, int len); struct vgic_irq *vgic_get_irq(struct kvm *kvm, struct kvm_vcpu *vcpu, u32 intid); -void __vgic_put_lpi_locked(struct kvm *kvm, struct vgic_irq *irq); void vgic_put_irq(struct kvm *kvm, struct vgic_irq *irq); bool vgic_get_phys_line_level(struct vgic_irq *irq); void vgic_irq_set_phys_pending(struct vgic_irq *irq, bool pending); --=20 2.44.0.rc0.258.g7320e95886-goog