From patchwork Thu Aug 10 12:30:51 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xuan Zhuo X-Patchwork-Id: 13349373 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 D4A5521D2C; Thu, 10 Aug 2023 12:31:12 +0000 (UTC) Received: from out30-111.freemail.mail.aliyun.com (out30-111.freemail.mail.aliyun.com [115.124.30.111]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 959252127; Thu, 10 Aug 2023 05:31:10 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R111e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045168;MF=xuanzhuo@linux.alibaba.com;NM=1;PH=DS;RN=15;SR=0;TI=SMTPD_---0VpTqSC5_1691670665; Received: from localhost(mailfrom:xuanzhuo@linux.alibaba.com fp:SMTPD_---0VpTqSC5_1691670665) by smtp.aliyun-inc.com; Thu, 10 Aug 2023 20:31:06 +0800 From: Xuan Zhuo To: virtualization@lists.linux-foundation.org Cc: "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , netdev@vger.kernel.org, bpf@vger.kernel.org, Christoph Hellwig Subject: [PATCH vhost v13 06/12] virtio_ring: skip unmap for premapped Date: Thu, 10 Aug 2023 20:30:51 +0800 Message-Id: <20230810123057.43407-7-xuanzhuo@linux.alibaba.com> X-Mailer: git-send-email 2.32.0.3.g01195cf9f In-Reply-To: <20230810123057.43407-1-xuanzhuo@linux.alibaba.com> References: <20230810123057.43407-1-xuanzhuo@linux.alibaba.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Git-Hash: 6ea114ee5d47 X-Spam-Status: No, score=-9.9 required=5.0 tests=BAYES_00, ENV_AND_HDR_SPF_MATCH,RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,USER_IN_DEF_SPF_WL autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Now we add a case where we skip dma unmap, the vq->premapped is true. We can't just rely on use_dma_api to determine whether to skip the dma operation. For convenience, I introduced the "do_unmap". By default, it is the same as use_dma_api. If the driver is configured with premapped, then do_unmap is false. So as long as do_unmap is false, for addr of desc, we should skip dma unmap operation. Signed-off-by: Xuan Zhuo --- drivers/virtio/virtio_ring.c | 42 ++++++++++++++++++++++++------------ 1 file changed, 28 insertions(+), 14 deletions(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index bb3d73d221cd..7973814b6e31 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -175,6 +175,11 @@ struct vring_virtqueue { /* Do DMA mapping by driver */ bool premapped; + /* Do unmap or not for desc. Just when premapped is False and + * use_dma_api is true, this is true. + */ + bool do_unmap; + /* Head of free buffer list. */ unsigned int free_head; /* Number we've added since last sync. */ @@ -440,7 +445,7 @@ static void vring_unmap_one_split_indirect(const struct vring_virtqueue *vq, { u16 flags; - if (!vq->use_dma_api) + if (!vq->do_unmap) return; flags = virtio16_to_cpu(vq->vq.vdev, desc->flags); @@ -458,18 +463,21 @@ static unsigned int vring_unmap_one_split(const struct vring_virtqueue *vq, struct vring_desc_extra *extra = vq->split.desc_extra; u16 flags; - if (!vq->use_dma_api) - goto out; - flags = extra[i].flags; if (flags & VRING_DESC_F_INDIRECT) { + if (!vq->use_dma_api) + goto out; + dma_unmap_single(vring_dma_dev(vq), extra[i].addr, extra[i].len, (flags & VRING_DESC_F_WRITE) ? DMA_FROM_DEVICE : DMA_TO_DEVICE); } else { + if (!vq->do_unmap) + goto out; + dma_unmap_page(vring_dma_dev(vq), extra[i].addr, extra[i].len, @@ -635,7 +643,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, } /* Last one doesn't continue. */ desc[prev].flags &= cpu_to_virtio16(_vq->vdev, ~VRING_DESC_F_NEXT); - if (!indirect && vq->use_dma_api) + if (!indirect && vq->do_unmap) vq->split.desc_extra[prev & (vq->split.vring.num - 1)].flags &= ~VRING_DESC_F_NEXT; @@ -794,7 +802,7 @@ static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head, VRING_DESC_F_INDIRECT)); BUG_ON(len == 0 || len % sizeof(struct vring_desc)); - if (vq->use_dma_api) { + if (vq->do_unmap) { for (j = 0; j < len / sizeof(struct vring_desc); j++) vring_unmap_one_split_indirect(vq, &indir_desc[j]); } @@ -1217,17 +1225,20 @@ static void vring_unmap_extra_packed(const struct vring_virtqueue *vq, { u16 flags; - if (!vq->use_dma_api) - return; - flags = extra->flags; if (flags & VRING_DESC_F_INDIRECT) { + if (!vq->use_dma_api) + return; + dma_unmap_single(vring_dma_dev(vq), extra->addr, extra->len, (flags & VRING_DESC_F_WRITE) ? DMA_FROM_DEVICE : DMA_TO_DEVICE); } else { + if (!vq->do_unmap) + return; + dma_unmap_page(vring_dma_dev(vq), extra->addr, extra->len, (flags & VRING_DESC_F_WRITE) ? @@ -1240,7 +1251,7 @@ static void vring_unmap_desc_packed(const struct vring_virtqueue *vq, { u16 flags; - if (!vq->use_dma_api) + if (!vq->do_unmap) return; flags = le16_to_cpu(desc->flags); @@ -1329,7 +1340,7 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq, sizeof(struct vring_packed_desc)); vq->packed.vring.desc[head].id = cpu_to_le16(id); - if (vq->use_dma_api) { + if (vq->do_unmap) { vq->packed.desc_extra[id].addr = addr; vq->packed.desc_extra[id].len = total_sg * sizeof(struct vring_packed_desc); @@ -1470,7 +1481,7 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq, desc[i].len = cpu_to_le32(sg->length); desc[i].id = cpu_to_le16(id); - if (unlikely(vq->use_dma_api)) { + if (unlikely(vq->do_unmap)) { vq->packed.desc_extra[curr].addr = addr; vq->packed.desc_extra[curr].len = sg->length; vq->packed.desc_extra[curr].flags = @@ -1604,7 +1615,7 @@ static void detach_buf_packed(struct vring_virtqueue *vq, vq->free_head = id; vq->vq.num_free += state->num; - if (unlikely(vq->use_dma_api)) { + if (unlikely(vq->do_unmap)) { curr = id; for (i = 0; i < state->num; i++) { vring_unmap_extra_packed(vq, @@ -1621,7 +1632,7 @@ static void detach_buf_packed(struct vring_virtqueue *vq, if (!desc) return; - if (vq->use_dma_api) { + if (vq->do_unmap) { len = vq->packed.desc_extra[id].len; for (i = 0; i < len / sizeof(struct vring_packed_desc); i++) @@ -2080,6 +2091,7 @@ static struct virtqueue *vring_create_virtqueue_packed( vq->dma_dev = dma_dev; vq->use_dma_api = vring_use_dma_api(vdev); vq->premapped = false; + vq->do_unmap = vq->use_dma_api; vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC) && !context; @@ -2587,6 +2599,7 @@ static struct virtqueue *__vring_new_virtqueue(unsigned int index, vq->dma_dev = dma_dev; vq->use_dma_api = vring_use_dma_api(vdev); vq->premapped = false; + vq->do_unmap = vq->use_dma_api; vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC) && !context; @@ -2771,6 +2784,7 @@ int virtqueue_set_dma_premapped(struct virtqueue *_vq) } vq->premapped = true; + vq->do_unmap = false; END_USE(vq);