From patchwork Fri Feb 16 18:41:53 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oliver Upton X-Patchwork-Id: 13560466 Received: from out-189.mta0.migadu.com (out-189.mta0.migadu.com [91.218.175.189]) (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 042E514830C for ; Fri, 16 Feb 2024 18:42:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.189 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708108948; cv=none; b=Pf1y1N74mQZ5iOMnDcDI1FZXYY1wLcIsvRlAxKuhy8aDOMMYPOFddBGU1xM7EtJbisaHmHKi2kVgL3259t5gOpP3cf1fjIgBmj5bq521YnW4CTE4qOIpGRVQ76hdH5NSgaAW5mMP64QBKbrkHculg47JWd7f6+9nFioOGULaQf0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708108948; c=relaxed/simple; bh=YOt99fgiOeGafpp1nEhSIUqA34CgCiK6op8GicPElws=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gqEmEcP0YzR9BYDhzsJFIA34Jd3Ry6nhRF0MspISQadu82KTlPwh5ZYeJp7vKGBQnvQRR6LQLCFwjBjXl4rs/jPfgyrnc+Q9rB64blZ52KadkaBvO7wf5lmmJXXdXZEjFVNjhb8O8xaHcfhv5FSBEQ4w9DCo6pqwBp3viDezd2U= 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=DLxdkdtb; arc=none smtp.client-ip=91.218.175.189 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="DLxdkdtb" 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=1708108944; 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=+6/2b6cdY93cfhwg+wgl1iJpv6T7icr8cPzff5WRiiM=; b=DLxdkdtbNwcuA4gLo4jd1yD05qIOD+omQNvakwfPpgTo6UMoTeIbl9XzhWZhJZwtRffA+j S6COGILK/oPKkNX85TmWz314nYUf1N7NFk3Rob9ONKeUXrHUuFrI9W4PpXWgZer+wkhrb/ NjTdniGek0pEoQhqcV0ARz6GeS0cHrQ= 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, Oliver Upton Subject: [PATCH v3 10/10] KVM: arm64: vgic: Don't acquire the lpi_list_lock in vgic_put_irq() Date: Fri, 16 Feb 2024 18:41:53 +0000 Message-ID: <20240216184153.2714504-11-oliver.upton@linux.dev> In-Reply-To: <20240216184153.2714504-1-oliver.upton@linux.dev> References: <20240216184153.2714504-1-oliver.upton@linux.dev> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT 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 | 21 ++++----------------- arch/arm64/kvm/vgic/vgic.h | 1 - 3 files changed, 6 insertions(+), 20 deletions(-) diff --git a/arch/arm64/kvm/vgic/vgic-its.c b/arch/arm64/kvm/vgic/vgic-its.c index c3d1bca0b458..d84cb7618c59 100644 --- a/arch/arm64/kvm/vgic/vgic-its.c +++ b/arch/arm64/kvm/vgic/vgic-its.c @@ -647,7 +647,7 @@ 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); /* * The irq refcount is guaranteed to be nonzero while holding the @@ -684,7 +684,7 @@ void vgic_its_invalidate_cache(struct kvm *kvm) if (!cte->irq) break; - __vgic_put_lpi_locked(kvm, cte->irq); + vgic_put_irq(kvm, cte->irq); cte->irq = NULL; } diff --git a/arch/arm64/kvm/vgic/vgic.c b/arch/arm64/kvm/vgic/vgic.c index 2a288d6c0be7..c8208f81fdc8 100644 --- a/arch/arm64/kvm/vgic/vgic.c +++ b/arch/arm64/kvm/vgic/vgic.c @@ -110,13 +110,13 @@ static void vgic_irq_release(struct kref *ref) { } -/* - * 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) +void vgic_put_irq(struct kvm *kvm, struct vgic_irq *irq) { struct vgic_dist *dist = &kvm->arch.vgic; + if (irq->intid < VGIC_MIN_LPI) + return; + if (!kref_put(&irq->refcount, vgic_irq_release)) return; @@ -126,19 +126,6 @@ void __vgic_put_lpi_locked(struct kvm *kvm, struct vgic_irq *irq) kfree_rcu(irq, rcu); } -void vgic_put_irq(struct kvm *kvm, struct vgic_irq *irq) -{ - struct vgic_dist *dist = &kvm->arch.vgic; - unsigned long flags; - - if (irq->intid < VGIC_MIN_LPI) - return; - - raw_spin_lock_irqsave(&dist->lpi_list_lock, flags); - __vgic_put_lpi_locked(kvm, irq); - raw_spin_unlock_irqrestore(&dist->lpi_list_lock, flags); -} - void vgic_flush_pending_lpis(struct kvm_vcpu *vcpu) { struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu; 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);