From nobody Wed Dec 17 12:05:27 2025 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 B490513A27E for ; Mon, 11 Nov 2024 02:55:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731293753; cv=none; b=YMHRcM2F/BTcmAGFwCE+W3cirlh9w6mv1awdto0DV7kDOFkcmYdFMCo4HgUj6xUocG9Eho8r2v8U2Tiku+PXhrP7q6RHY3nTA+dQ9u12+xizivfNB/c5zPZtuNFZT0InODpElBH2Qz+sk2Q5gZ2AA+PAd/Wf641QybkEG/63EJY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731293753; c=relaxed/simple; bh=1ZvxRezxJXANBRFOTe55Jek5Kex2eZTOtcEtydvGZOM=; h=From:To:Subject:Date:Message-ID:MIME-Version; b=Jno98k/W8vMV/7d5NKFd2WmaisUlaD9eZGgX/UvWMjZyhIOlKnj2L6LfUudAsglKqcutQ64+0ovsz0SNLWrOVh2lP5qNhxQ+UACkzkcPvFS/6nM3DjjVGdATLv+XYNWKCycSYmL0OO6qXBS3q/2U/dAgdAo1BddNKevjpHyO6v8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=ZbY3mOPY; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ZbY3mOPY" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1731293750; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=+y3vCNcj9tlE1RFyrQIwWNkyVgS7ApkQcRy6pVYNX4E=; b=ZbY3mOPYjS/nTh3nmA9F9Kua3OAe42NiQGvds3WFCv1snG0M0gmUw65NYq4I7PreqPMbY9 CzoUjaHJXZj0+QUZYNglfxTZLz7zLqtKxWZmwJ8dGXiQtNc+Z4IKuLEj94fTOfr96kaaRW U+0QMR6WLH1ZuMXi8iMexXMIPtmXs1I= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-433-35vZMN0xO-u4pwZIi-lSWw-1; Sun, 10 Nov 2024 21:55:47 -0500 X-MC-Unique: 35vZMN0xO-u4pwZIi-lSWw-1 X-Mimecast-MFC-AGG-ID: 35vZMN0xO-u4pwZIi-lSWw Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 3C31E195608C; Mon, 11 Nov 2024 02:55:46 +0000 (UTC) Received: from localhost.localdomain (unknown [10.72.112.237]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 970DA300019E; Mon, 11 Nov 2024 02:55:40 +0000 (UTC) From: Jason Wang To: mst@redhat.com, jasowang@redhat.com, xuanzhuo@linux.alibaba.com, eperezma@redhat.com, virtualization@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH] virtio_ring: skip cpu sync when mapping fails Date: Mon, 11 Nov 2024 10:55:38 +0800 Message-ID: <20241111025538.2837-1-jasowang@redhat.com> 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-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Content-Type: text/plain; charset="utf-8" There's no need to sync DMA for CPU on mapping errors. So this patch skips the CPU sync in the error handling path of DMA mapping. Signed-off-by: Jason Wang Reviewed-by: Xuan Zhuo --- drivers/virtio/virtio_ring.c | 98 +++++++++++++++++++++--------------- 1 file changed, 57 insertions(+), 41 deletions(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index be7309b1e860..b422b5fb22db 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -441,8 +441,10 @@ static void virtqueue_init(struct vring_virtqueue *vq,= u32 num) */ =20 static void vring_unmap_one_split_indirect(const struct vring_virtqueue *v= q, - const struct vring_desc *desc) + const struct vring_desc *desc, + bool skip_sync) { + unsigned long attrs =3D skip_sync ? DMA_ATTR_SKIP_CPU_SYNC : 0; u16 flags; =20 if (!vq->do_unmap) @@ -450,16 +452,18 @@ static void vring_unmap_one_split_indirect(const stru= ct vring_virtqueue *vq, =20 flags =3D virtio16_to_cpu(vq->vq.vdev, desc->flags); =20 - dma_unmap_page(vring_dma_dev(vq), - virtio64_to_cpu(vq->vq.vdev, desc->addr), - virtio32_to_cpu(vq->vq.vdev, desc->len), - (flags & VRING_DESC_F_WRITE) ? - DMA_FROM_DEVICE : DMA_TO_DEVICE); + dma_unmap_page_attrs(vring_dma_dev(vq), + virtio64_to_cpu(vq->vq.vdev, desc->addr), + virtio32_to_cpu(vq->vq.vdev, desc->len), + (flags & VRING_DESC_F_WRITE) ? + DMA_FROM_DEVICE : DMA_TO_DEVICE, + attrs); } =20 static unsigned int vring_unmap_one_split(const struct vring_virtqueue *vq, - unsigned int i) + unsigned int i, bool skip_sync) { + unsigned long attrs =3D skip_sync ? DMA_ATTR_SKIP_CPU_SYNC : 0; struct vring_desc_extra *extra =3D vq->split.desc_extra; u16 flags; =20 @@ -469,20 +473,22 @@ static unsigned int vring_unmap_one_split(const struc= t vring_virtqueue *vq, if (!vq->use_dma_api) goto out; =20 - dma_unmap_single(vring_dma_dev(vq), - extra[i].addr, - extra[i].len, - (flags & VRING_DESC_F_WRITE) ? - DMA_FROM_DEVICE : DMA_TO_DEVICE); + dma_unmap_single_attrs(vring_dma_dev(vq), + extra[i].addr, + extra[i].len, + (flags & VRING_DESC_F_WRITE) ? + DMA_FROM_DEVICE : DMA_TO_DEVICE, + attrs); } else { if (!vq->do_unmap) goto out; =20 - dma_unmap_page(vring_dma_dev(vq), - extra[i].addr, - extra[i].len, - (flags & VRING_DESC_F_WRITE) ? - DMA_FROM_DEVICE : DMA_TO_DEVICE); + dma_unmap_page_attrs(vring_dma_dev(vq), + extra[i].addr, + extra[i].len, + (flags & VRING_DESC_F_WRITE) ? + DMA_FROM_DEVICE : DMA_TO_DEVICE, + attrs); } =20 out: @@ -717,10 +723,10 @@ static inline int virtqueue_add_split(struct virtqueu= e *_vq, if (i =3D=3D err_idx) break; if (indirect) { - vring_unmap_one_split_indirect(vq, &desc[i]); + vring_unmap_one_split_indirect(vq, &desc[i], true); i =3D virtio16_to_cpu(_vq->vdev, desc[i].next); } else - i =3D vring_unmap_one_split(vq, i); + i =3D vring_unmap_one_split(vq, i, true); } =20 free_indirect: @@ -775,12 +781,12 @@ static void detach_buf_split(struct vring_virtqueue *= vq, unsigned int head, i =3D head; =20 while (vq->split.vring.desc[i].flags & nextflag) { - vring_unmap_one_split(vq, i); + vring_unmap_one_split(vq, i, false); i =3D vq->split.desc_extra[i].next; vq->vq.num_free++; } =20 - vring_unmap_one_split(vq, i); + vring_unmap_one_split(vq, i, false); vq->split.desc_extra[i].next =3D vq->free_head; vq->free_head =3D head; =20 @@ -804,7 +810,8 @@ static void detach_buf_split(struct vring_virtqueue *vq= , unsigned int head, =20 if (vq->do_unmap) { for (j =3D 0; j < len / sizeof(struct vring_desc); j++) - vring_unmap_one_split_indirect(vq, &indir_desc[j]); + vring_unmap_one_split_indirect(vq, + &indir_desc[j], false); } =20 kfree(indir_desc); @@ -1221,8 +1228,10 @@ static u16 packed_last_used(u16 last_used_idx) } =20 static void vring_unmap_extra_packed(const struct vring_virtqueue *vq, - const struct vring_desc_extra *extra) + const struct vring_desc_extra *extra, + bool skip_sync) { + unsigned long attrs =3D skip_sync ? DMA_ATTR_SKIP_CPU_SYNC : 0; u16 flags; =20 flags =3D extra->flags; @@ -1231,24 +1240,28 @@ static void vring_unmap_extra_packed(const struct v= ring_virtqueue *vq, if (!vq->use_dma_api) return; =20 - dma_unmap_single(vring_dma_dev(vq), - extra->addr, extra->len, - (flags & VRING_DESC_F_WRITE) ? - DMA_FROM_DEVICE : DMA_TO_DEVICE); + dma_unmap_single_attrs(vring_dma_dev(vq), + extra->addr, extra->len, + (flags & VRING_DESC_F_WRITE) ? + DMA_FROM_DEVICE : DMA_TO_DEVICE, + attrs); } else { if (!vq->do_unmap) return; =20 - dma_unmap_page(vring_dma_dev(vq), - extra->addr, extra->len, - (flags & VRING_DESC_F_WRITE) ? - DMA_FROM_DEVICE : DMA_TO_DEVICE); + dma_unmap_page_attrs(vring_dma_dev(vq), + extra->addr, extra->len, + (flags & VRING_DESC_F_WRITE) ? + DMA_FROM_DEVICE : DMA_TO_DEVICE, + attrs); } } =20 static void vring_unmap_desc_packed(const struct vring_virtqueue *vq, - const struct vring_packed_desc *desc) + const struct vring_packed_desc *desc, + bool skip_sync) { + unsigned long attrs =3D skip_sync ? DMA_ATTR_SKIP_CPU_SYNC : 0; u16 flags; =20 if (!vq->do_unmap) @@ -1256,11 +1269,12 @@ static void vring_unmap_desc_packed(const struct vr= ing_virtqueue *vq, =20 flags =3D le16_to_cpu(desc->flags); =20 - dma_unmap_page(vring_dma_dev(vq), - le64_to_cpu(desc->addr), - le32_to_cpu(desc->len), - (flags & VRING_DESC_F_WRITE) ? - DMA_FROM_DEVICE : DMA_TO_DEVICE); + dma_unmap_page_attrs(vring_dma_dev(vq), + le64_to_cpu(desc->addr), + le32_to_cpu(desc->len), + (flags & VRING_DESC_F_WRITE) ? + DMA_FROM_DEVICE : DMA_TO_DEVICE, + attrs); } =20 static struct vring_packed_desc *alloc_indirect_packed(unsigned int total_= sg, @@ -1389,7 +1403,7 @@ static int virtqueue_add_indirect_packed(struct vring= _virtqueue *vq, err_idx =3D i; =20 for (i =3D 0; i < err_idx; i++) - vring_unmap_desc_packed(vq, &desc[i]); + vring_unmap_desc_packed(vq, &desc[i], true); =20 free_desc: kfree(desc); @@ -1539,7 +1553,8 @@ static inline int virtqueue_add_packed(struct virtque= ue *_vq, for (n =3D 0; n < total_sg; n++) { if (i =3D=3D err_idx) break; - vring_unmap_extra_packed(vq, &vq->packed.desc_extra[curr]); + vring_unmap_extra_packed(vq, + &vq->packed.desc_extra[curr], true); curr =3D vq->packed.desc_extra[curr].next; i++; if (i >=3D vq->packed.vring.num) @@ -1619,7 +1634,8 @@ static void detach_buf_packed(struct vring_virtqueue = *vq, curr =3D id; for (i =3D 0; i < state->num; i++) { vring_unmap_extra_packed(vq, - &vq->packed.desc_extra[curr]); + &vq->packed.desc_extra[curr], + false); curr =3D vq->packed.desc_extra[curr].next; } } @@ -1636,7 +1652,7 @@ static void detach_buf_packed(struct vring_virtqueue = *vq, len =3D vq->packed.desc_extra[id].len; for (i =3D 0; i < len / sizeof(struct vring_packed_desc); i++) - vring_unmap_desc_packed(vq, &desc[i]); + vring_unmap_desc_packed(vq, &desc[i], false); } kfree(desc); state->indir_desc =3D NULL; --=20 2.31.1