From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 0780A1C5D6A for ; Tue, 1 Jul 2025 06:57:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751353025; cv=none; b=RHtj7BL4p5/z2AXnNUUS0GMi9LRvf4EdZtjArDs6e5v7J0159WObhSmtKC8shjIXZmqM9kidbA10W/Oq1ZXL3SW4H0tTXJN61pLp2EROa58HkcnkyFwY/1ZeHePhxiogAifD2WnAjoJxOtPXXGrdFIZblesec2zdxo1cMlPG9vU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751353025; c=relaxed/simple; bh=UEFN4KLiR+/IitdJC8eiehgjgqvaD2EoaUazsSyBHEA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=BIkbimo0GW01yVN+fyVI29U6z8YxNNIB398PSxUtFZz8XHIhYyVXwwetwHZZ45X6tYaTNq7DCGOzvCT7VQewxb99GeQqvSNoiwmxF/0zwp350lqP6Nn4ho0dZLGIHlh+mThDPkuVVOfieONiuIYf/tNxw448oonBV1ChZXG2O0s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine 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=jST/m83w; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine 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="jST/m83w" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1751353021; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ItnFVB/TlEsRcmFSPBspkFzgPaduotrpjyBjgLNisIs=; b=jST/m83w58um8/VIVCx4fE/vu5N5aDrIJCbvLKMXkkiefWWXqz6Xo9rmedI16/gnl39JV0 crJVdudlNFEGPO9rYk8r97q4PpHkPw4RUJQxVGgGQVfb3ZV/posvxmXYNu48FW1yt4xxBq MeSm8krCklMLA5Z6CBuqV7r56F5Ebmk= Received: from mail-wr1-f72.google.com (mail-wr1-f72.google.com [209.85.221.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-88-GOJrhymHMMSOTLXBFvip2Q-1; Tue, 01 Jul 2025 02:57:00 -0400 X-MC-Unique: GOJrhymHMMSOTLXBFvip2Q-1 X-Mimecast-MFC-AGG-ID: GOJrhymHMMSOTLXBFvip2Q_1751353019 Received: by mail-wr1-f72.google.com with SMTP id ffacd0b85a97d-3a579058758so1031709f8f.1 for ; Mon, 30 Jun 2025 23:57:00 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1751353019; x=1751957819; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=ItnFVB/TlEsRcmFSPBspkFzgPaduotrpjyBjgLNisIs=; b=X09716xxMKmMHTbWfuQCLgiTNTXK0wgHGmrDWTMdsPmSGwTo8KvKHwoJv1AxAlzs5N sTF5jBY8J1lfzMJ6d85Yrl6PwJb+o/s9Nvo/0qC4O9LOund7JDTEMOwCkn252Mp3UoVE NNNU5959o99wXJsGbtmOpRG2HQz2xXNb3dKSUrYqMEXNo5y2bzqdQ01zGltnX+KL/tbc hssei3LDUG5tYFvoc6wmWV25t4GfsV2EVoawMRUYcx0DK1iPZ1RwtOsUH7ff67kzfRZ2 bxKdKcalNfUGM5ktUKyxVRzTm+5ZQhJWDucUO9fF+Ebb9/kL7O9bje8tUNHF782ryA+W cg6A== X-Forwarded-Encrypted: i=1; AJvYcCX7AfJ4eOF+4FM3AwUOWDUQrBs9eP74zbqvdTDCdFNURaCWoAD0jqlmVnxC5FI/63qirNjj1gcvRc2uPXI=@vger.kernel.org X-Gm-Message-State: AOJu0YyLIRQHzPjVtMgzWzanEZwDuUXWy733OknU5DRZOd6fw/cIPemg aOL48AV/OX6jRJGGp/hjITRQUkYYIq5kTqh4/W7HhWaWQdS9CvOvax/pSRY0me6R8t+OCc8Xvy1 InQoORFUYAfC3lAApKwy6ijL6DDav4w8waac17DVip2y+Le0y9N5vqlWcFoh//UruJQ== X-Gm-Gg: ASbGncs3lBZGkI9+GJmYdJMM12q3tCA7VIZ9Nbc8UpkquDJay1sus096aXjeGGjM0W4 +9sZpxprSn+4rfp0QzqYF2DvPlUhIJGIkJv+7NZVx+mDaL4hEn7gYyoz8ITtAniVRuGyIvOn0Ix PqL+iWmFbx0fNYtYKxaIwcxb6ZbsE/LoGR9mY1+oGKND8p5KvGWgDWRL1F7wzehxuz1PQLl0oNJ uirzRFHk7xlV+XVraDnlR1RRTKn9bzonvR4y02n19WD16m3MrjZLm8rlIVKQoDFATiK01xhQHM1 rHI9o6Ebv2Re45tb X-Received: by 2002:a05:6000:2311:b0:3a4:dfc2:bb60 with SMTP id ffacd0b85a97d-3a8f54a07bcmr14405674f8f.26.1751353018843; Mon, 30 Jun 2025 23:56:58 -0700 (PDT) X-Google-Smtp-Source: AGHT+IFJR3YN2BCqTYfxDweVcpAN+nhsAXlycTv8ax/pHpHLAvm7RmaebUSW7I44E4H9trZStjWYcg== X-Received: by 2002:a05:6000:2311:b0:3a4:dfc2:bb60 with SMTP id ffacd0b85a97d-3a8f54a07bcmr14405649f8f.26.1751353018243; Mon, 30 Jun 2025 23:56:58 -0700 (PDT) Received: from redhat.com ([2a0d:6fc0:152e:1400:856d:9957:3ec3:1ddc]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4538a3a5fd2sm155150445e9.15.2025.06.30.23.56.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 30 Jun 2025 23:56:57 -0700 (PDT) Date: Tue, 1 Jul 2025 02:56:55 -0400 From: "Michael S. Tsirkin" To: Jason Wang Cc: xuanzhuo@linux.alibaba.com, eperezma@redhat.com, virtualization@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH V3 19/19] virtio_ring: add in order support Message-ID: <20250701024602-mutt-send-email-mst@kernel.org> References: <20250616082518.10411-1-jasowang@redhat.com> <20250616082518.10411-20-jasowang@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250616082518.10411-20-jasowang@redhat.com> On Mon, Jun 16, 2025 at 04:25:17PM +0800, Jason Wang wrote: > This patch implements in order support for both split virtqueue and > packed virtqueue. I'd like to see more motivation for this work, documented. It's not really performance, not as it stands, see below: > > Benchmark with KVM guest + testpmd on the host shows: > > For split virtqueue: no obvious differences were noticed > > For packed virtqueue: > > 1) RX gets 3.1% PPS improvements from 6.3 Mpps to 6.5 Mpps > 2) TX gets 4.6% PPS improvements from 8.6 Mpps to 9.0 Mpps > That's a very modest improvement for a lot of code. I also note you put in some batching just for in-order. Which could also explain the gains maybe? What if you just put in a simple implementation with no batching tricks? do you still see a gain? Does any hardware implement this? Maybe that can demonstrate bigger gains. > Signed-off-by: Jason Wang > --- > drivers/virtio/virtio_ring.c | 423 +++++++++++++++++++++++++++++++++-- > 1 file changed, 402 insertions(+), 21 deletions(-) > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > index 27a9459a0555..21d456392ba0 100644 > --- a/drivers/virtio/virtio_ring.c > +++ b/drivers/virtio/virtio_ring.c > @@ -70,11 +70,14 @@ > enum vq_layout { > SPLIT = 0, > PACKED, > + SPLIT_IN_ORDER, > + PACKED_IN_ORDER, > VQ_TYPE_MAX, > }; > > struct vring_desc_state_split { > void *data; /* Data for callback. */ > + u32 total_len; /* Buffer Length */ > > /* Indirect desc table and extra table, if any. These two will be > * allocated together. So we won't stress more to the memory allocator. > @@ -84,6 +87,7 @@ struct vring_desc_state_split { > > struct vring_desc_state_packed { > void *data; /* Data for callback. */ > + u32 total_len; /* Buffer Length */ > > /* Indirect desc table and extra table, if any. These two will be > * allocated together. So we won't stress more to the memory allocator. We are bloating up the cache footprint for everyone, so there's a chance of regressions. Pls include benchmark for in order off, to make sure we are not regressing. How big was the ring? Worth trying with a biggish one, where there is more cache pressure. Why not have a separate state for in-order? > @@ -206,6 +210,12 @@ struct vring_virtqueue { > > /* Head of free buffer list. */ > unsigned int free_head; > + > + /* Head of the batched used buffers, vq->num means no batching */ > + unsigned int batch_head; > + > + unsigned int batch_len; > + Are these two only used for in-order? Please document that. I also want some documentation about the batching trickery used please. What is batched, when, how is batching flushed, why are we only batching in-order ... > /* Number we've added since last sync. */ > unsigned int num_added; > > @@ -256,10 +266,14 @@ static void vring_free(struct virtqueue *_vq); > > #define to_vvq(_vq) container_of_const(_vq, struct vring_virtqueue, vq) > > - > static inline bool virtqueue_is_packed(const struct vring_virtqueue *vq) > { > - return vq->layout == PACKED; > + return vq->layout == PACKED || vq->layout == PACKED_IN_ORDER; > +} > + > +static inline bool virtqueue_is_in_order(const struct vring_virtqueue *vq) > +{ > + return vq->layout == SPLIT_IN_ORDER || vq->layout == PACKED_IN_ORDER; > } > > static bool virtqueue_use_indirect(const struct vring_virtqueue *vq, > @@ -570,7 +584,7 @@ static inline int virtqueue_add_split(struct vring_virtqueue *vq, > struct vring_desc_extra *extra; > struct scatterlist *sg; > struct vring_desc *desc; > - unsigned int i, n, c, avail, descs_used, err_idx; > + unsigned int i, n, c, avail, descs_used, err_idx, total_len = 0; I would add a comment here: /* Total length for in-order */ unsigned int total_len = 0; > int head; > bool indirect; > > @@ -646,6 +660,7 @@ static inline int virtqueue_add_split(struct vring_virtqueue *vq, > i = virtqueue_add_desc_split(vq, desc, extra, i, addr, len, > flags, > premapped); > + total_len += len; > } > } > for (; n < (out_sgs + in_sgs); n++) { > @@ -665,6 +680,7 @@ static inline int virtqueue_add_split(struct vring_virtqueue *vq, > */ > i = virtqueue_add_desc_split(vq, desc, extra, i, addr, len, > flags, premapped); > + total_len += len; > } > } > > @@ -687,7 +703,12 @@ static inline int virtqueue_add_split(struct vring_virtqueue *vq, > vq->vq.num_free -= descs_used; > > /* Update free pointer */ > - if (indirect) > + if (virtqueue_is_in_order(vq)) { > + vq->free_head += descs_used; > + if (vq->free_head >= vq->split.vring.num) > + vq->free_head -= vq->split.vring.num; > + vq->split.desc_state[head].total_len = total_len;; > + } else if (indirect) > vq->free_head = vq->split.desc_extra[head].next; > else > vq->free_head = i; > @@ -860,6 +881,14 @@ static bool more_used_split(const struct vring_virtqueue *vq) > return virtqueue_poll_split(vq, vq->last_used_idx); > } > > +static bool more_used_split_in_order(const struct vring_virtqueue *vq) > +{ > + if (vq->batch_head != vq->packed.vring.num) > + return true; > + > + return virtqueue_poll_split(vq, vq->last_used_idx); > +} > + > static void *virtqueue_get_buf_ctx_split(struct vring_virtqueue *vq, > unsigned int *len, > void **ctx) > @@ -917,6 +946,73 @@ static void *virtqueue_get_buf_ctx_split(struct vring_virtqueue *vq, > return ret; > } > > +static void *virtqueue_get_buf_ctx_split_in_order(struct vring_virtqueue *vq, > + unsigned int *len, > + void **ctx) > +{ > + void *ret; > + unsigned int num = vq->split.vring.num; > + u16 last_used; > + > + START_USE(vq); > + > + if (unlikely(vq->broken)) { > + END_USE(vq); > + return NULL; > + } > + > + last_used = (vq->last_used_idx & (vq->split.vring.num - 1)); > + > + if (vq->batch_head == num) { > + if (!more_used_split(vq)) { > + pr_debug("No more buffers in queue\n"); > + END_USE(vq); > + return NULL; > + } > + > + /* Only get used array entries after they have been > + * exposed by host. */ > + virtio_rmb(vq->weak_barriers); > + vq->batch_head = virtio32_to_cpu(vq->vq.vdev, > + vq->split.vring.used->ring[last_used].id); > + vq->batch_len = virtio32_to_cpu(vq->vq.vdev, > + vq->split.vring.used->ring[last_used].len); > + } > + > + if (vq->batch_head == last_used) { > + vq->batch_head = num; > + *len = vq->batch_len; > + } else > + *len = vq->split.desc_state[last_used].total_len; > + > + if (unlikely(last_used >= num)) { > + BAD_RING(vq, "id %u out of range\n", last_used); > + return NULL; > + } > + if (unlikely(!vq->split.desc_state[last_used].data)) { > + BAD_RING(vq, "id %u is not a head!\n", last_used); > + return NULL; > + } > + > + /* detach_buf_split clears data, so grab it now. */ > + ret = vq->split.desc_state[last_used].data; > + detach_buf_split_in_order(vq, last_used, ctx); > + > + vq->last_used_idx++; > + /* If we expect an interrupt for the next entry, tell host > + * by writing event index and flush out the write before > + * the read in the next get_buf call. */ > + if (!(vq->split.avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT)) > + virtio_store_mb(vq->weak_barriers, > + &vring_used_event(&vq->split.vring), > + cpu_to_virtio16(vq->vq.vdev, vq->last_used_idx)); > + > + LAST_ADD_TIME_INVALID(vq); > + > + END_USE(vq); > + return ret; > +} > + > static void virtqueue_disable_cb_split(struct vring_virtqueue *vq) > { > if (!(vq->split.avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT)) { > @@ -1010,7 +1106,10 @@ static void *virtqueue_detach_unused_buf_split(struct vring_virtqueue *vq) > continue; > /* detach_buf_split clears data, so grab it now. */ > buf = vq->split.desc_state[i].data; > - detach_buf_split(vq, i, NULL); > + if (virtqueue_is_in_order(vq)) > + detach_buf_split_in_order(vq, i, NULL); > + else > + detach_buf_split(vq, i, NULL); > vq->split.avail_idx_shadow--; > vq->split.vring.avail->idx = cpu_to_virtio16(vq->vq.vdev, > vq->split.avail_idx_shadow); > @@ -1073,6 +1172,7 @@ static void virtqueue_vring_attach_split(struct vring_virtqueue *vq, > > /* Put everything in free lists. */ > vq->free_head = 0; > + vq->batch_head = vq->split.vring.num; > } > > static int vring_alloc_state_extra_split(struct vring_virtqueue_split *vring_split) > @@ -1183,7 +1283,6 @@ static struct virtqueue *__vring_new_virtqueue_split(unsigned int index, > if (!vq) > return NULL; > > - vq->layout = SPLIT; > vq->vq.callback = callback; > vq->vq.vdev = vdev; > vq->vq.name = name; > @@ -1203,6 +1302,8 @@ static struct virtqueue *__vring_new_virtqueue_split(unsigned int index, > vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC) && > !context; > vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX); > + vq->layout = virtio_has_feature(vdev, VIRTIO_F_IN_ORDER) ? > + SPLIT_IN_ORDER : SPLIT; > > if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM)) > vq->weak_barriers = false; > @@ -1366,13 +1467,14 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq, > unsigned int in_sgs, > void *data, > bool premapped, > - gfp_t gfp) > + gfp_t gfp, > + u16 id) > { > struct vring_desc_extra *extra; > struct vring_packed_desc *desc; > struct scatterlist *sg; > - unsigned int i, n, err_idx, len; > - u16 head, id; > + unsigned int i, n, err_idx, len, total_len = 0; > + u16 head; > dma_addr_t addr; > > head = vq->packed.next_avail_idx; > @@ -1390,8 +1492,6 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq, > } > > i = 0; > - id = vq->free_head; > - BUG_ON(id == vq->packed.vring.num); > > for (n = 0; n < out_sgs + in_sgs; n++) { > for (sg = sgs[n]; sg; sg = sg_next(sg)) { > @@ -1411,6 +1511,7 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq, > extra[i].flags = n < out_sgs ? 0 : VRING_DESC_F_WRITE; > } > > + total_len += len; > i++; > } > } > @@ -1464,6 +1565,7 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq, > vq->packed.desc_state[id].data = data; > vq->packed.desc_state[id].indir_desc = desc; > vq->packed.desc_state[id].last = id; > + vq->packed.desc_state[id].total_len = total_len; > > vq->num_added += 1; > > @@ -1516,8 +1618,11 @@ static inline int virtqueue_add_packed(struct vring_virtqueue *vq, > BUG_ON(total_sg == 0); > > if (virtqueue_use_indirect(vq, total_sg)) { > + id = vq->free_head; > + BUG_ON(id == vq->packed.vring.num); > err = virtqueue_add_indirect_packed(vq, sgs, total_sg, out_sgs, > - in_sgs, data, premapped, gfp); > + in_sgs, data, premapped, > + gfp, id); > if (err != -ENOMEM) { > END_USE(vq); > return err; > @@ -1638,6 +1743,152 @@ static inline int virtqueue_add_packed(struct vring_virtqueue *vq, > return -EIO; > } > > +static inline int virtqueue_add_packed_in_order(struct vring_virtqueue *vq, > + struct scatterlist *sgs[], > + unsigned int total_sg, > + unsigned int out_sgs, > + unsigned int in_sgs, > + void *data, > + void *ctx, > + bool premapped, > + gfp_t gfp) > +{ > + struct vring_packed_desc *desc; > + struct scatterlist *sg; > + unsigned int i, n, c, err_idx, total_len = 0; > + __le16 head_flags, flags; > + u16 head, avail_used_flags; > + int err; > + > + START_USE(vq); > + > + BUG_ON(data == NULL); > + BUG_ON(ctx && vq->indirect); > + > + if (unlikely(vq->broken)) { > + END_USE(vq); > + return -EIO; > + } > + > + LAST_ADD_TIME_UPDATE(vq); > + > + BUG_ON(total_sg == 0); > + > + if (virtqueue_use_indirect(vq, total_sg)) { > + err = virtqueue_add_indirect_packed(vq, sgs, total_sg, out_sgs, > + in_sgs, data, premapped, gfp, > + vq->packed.next_avail_idx); > + if (err != -ENOMEM) { > + END_USE(vq); > + return err; > + } > + > + /* fall back on direct */ > + } > + > + head = vq->packed.next_avail_idx; > + avail_used_flags = vq->packed.avail_used_flags; > + > + WARN_ON_ONCE(total_sg > vq->packed.vring.num && !vq->indirect); > + > + desc = vq->packed.vring.desc; > + i = head; > + > + if (unlikely(vq->vq.num_free < total_sg)) { > + pr_debug("Can't add buf len %i - avail = %i\n", > + total_sg, vq->vq.num_free); > + END_USE(vq); > + return -ENOSPC; > + } > + > + c = 0; > + for (n = 0; n < out_sgs + in_sgs; n++) { > + for (sg = sgs[n]; sg; sg = sg_next(sg)) { > + dma_addr_t addr; > + u32 len; > + > + if (vring_map_one_sg(vq, sg, n < out_sgs ? > + DMA_TO_DEVICE : DMA_FROM_DEVICE, > + &addr, &len, premapped)) > + goto unmap_release; > + > + flags = cpu_to_le16(vq->packed.avail_used_flags | > + (++c == total_sg ? 0 : VRING_DESC_F_NEXT) | > + (n < out_sgs ? 0 : VRING_DESC_F_WRITE)); > + if (i == head) > + head_flags = flags; > + else > + desc[i].flags = flags; > + > + > + desc[i].addr = cpu_to_le64(addr); > + desc[i].len = cpu_to_le32(len); > + desc[i].id = cpu_to_le16(head); > + > + if (unlikely(vq->use_dma_api)) { > + vq->packed.desc_extra[i].addr = premapped ? > + DMA_MAPPING_ERROR: addr; > + vq->packed.desc_extra[i].len = len; > + vq->packed.desc_extra[i].flags = > + le16_to_cpu(flags); > + } > + > + if ((unlikely(++i >= vq->packed.vring.num))) { > + i = 0; > + vq->packed.avail_used_flags ^= > + 1 << VRING_PACKED_DESC_F_AVAIL | > + 1 << VRING_PACKED_DESC_F_USED; > + vq->packed.avail_wrap_counter ^= 1; > + } > + > + total_len += len; > + } > + } > + > + /* We're using some buffers from the free list. */ > + vq->vq.num_free -= total_sg; > + > + /* Update free pointer */ > + vq->packed.next_avail_idx = i; > + > + /* Store token. */ > + vq->packed.desc_state[head].num = total_sg; > + vq->packed.desc_state[head].data = data; > + vq->packed.desc_state[head].indir_desc = ctx; > + vq->packed.desc_state[head].total_len = total_len; > + > + /* > + * A driver MUST NOT make the first descriptor in the list > + * available before all subsequent descriptors comprising > + * the list are made available. > + */ > + virtio_wmb(vq->weak_barriers); > + vq->packed.vring.desc[head].flags = head_flags; > + vq->num_added += total_sg; > + > + pr_debug("Added buffer head %i to %p\n", head, vq); > + END_USE(vq); > + > + return 0; > + > +unmap_release: > + err_idx = i; > + i = head; > + vq->packed.avail_used_flags = avail_used_flags; > + > + for (n = 0; n < total_sg; n++) { > + if (i == err_idx) > + break; > + vring_unmap_extra_packed(vq, &vq->packed.desc_extra[i]); > + i++; > + if (i >= vq->packed.vring.num) > + i = 0; > + } > + > + END_USE(vq); > + return -EIO; > +} > + > static bool virtqueue_kick_prepare_packed(struct vring_virtqueue *vq) > { > u16 new, old, off_wrap, flags, wrap_counter, event_idx; > @@ -1758,7 +2009,7 @@ static inline bool is_used_desc_packed(const struct vring_virtqueue *vq, > return avail == used && used == used_wrap_counter; > } > > -static bool virtqueue_poll_packed(const struct vring_virtqueue *vq, u16 off_wrap) > +static bool __virtqueue_poll_packed(const struct vring_virtqueue *vq, u16 off_wrap) > { > bool wrap_counter; > u16 used_idx; > @@ -1769,6 +2020,11 @@ static bool virtqueue_poll_packed(const struct vring_virtqueue *vq, u16 off_wrap > return is_used_desc_packed(vq, used_idx, wrap_counter); > } > > +static bool virtqueue_poll_packed(const struct vring_virtqueue *vq, u16 off_wrap) > +{ > + return __virtqueue_poll_packed(vq, off_wrap); > +} > + > static bool more_used_packed(const struct vring_virtqueue *vq) > { > return virtqueue_poll_packed(vq, READ_ONCE(vq->last_used_idx)); > @@ -1798,10 +2054,84 @@ static void update_last_used_idx_packed(struct vring_virtqueue *vq, > cpu_to_le16(vq->last_used_idx)); > } > > +static bool more_used_packed_in_order(const struct vring_virtqueue *vq) > +{ > + if (vq->batch_head != vq->packed.vring.num) > + return true; > + > + return virtqueue_poll_packed(vq, READ_ONCE(vq->last_used_idx)); > +} > + > +static bool __more_used_packed(const struct vring_virtqueue *vq) > +{ > + return __virtqueue_poll_packed(vq, READ_ONCE(vq->last_used_idx)); > +} > + > +static void *virtqueue_get_buf_ctx_packed_in_order(struct vring_virtqueue *vq, > + unsigned int *len, > + void **ctx) > +{ > + unsigned int num = vq->packed.vring.num; > + u16 last_used, id, last_used_idx; > + bool used_wrap_counter; > + void *ret; > + > + START_USE(vq); > + > + if (unlikely(vq->broken)) { > + END_USE(vq); > + return NULL; > + } > + > + last_used_idx = vq->last_used_idx; > + used_wrap_counter = packed_used_wrap_counter(last_used_idx); > + last_used = packed_last_used(last_used_idx); > + > + if (vq->batch_head == num) { > + if (!__more_used_packed(vq)) { > + pr_debug("No more buffers in queue\n"); > + END_USE(vq); > + return NULL; > + } > + /* Only get used elements after they have been exposed by host. */ > + virtio_rmb(vq->weak_barriers); > + vq->batch_head = le16_to_cpu(vq->packed.vring.desc[last_used].id); > + vq->batch_len = le32_to_cpu(vq->packed.vring.desc[last_used].len); > + } > + > + if (vq->batch_head == last_used) { > + vq->batch_head = num; > + *len = vq->batch_len; > + } else > + *len = vq->packed.desc_state[last_used].total_len; > + > + if (unlikely(last_used >= num)) { > + BAD_RING(vq, "id %u out of range\n", id); > + return NULL; > + } > + if (unlikely(!vq->packed.desc_state[last_used].data)) { > + BAD_RING(vq, "id %u is not a head!\n", id); > + return NULL; > + } > + > + /* detach_buf_packed clears data, so grab it now. */ > + ret = vq->packed.desc_state[last_used].data; > + detach_buf_packed_in_order(vq, last_used, ctx); > + > + update_last_used_idx_packed(vq, last_used, last_used, > + used_wrap_counter); > + > + LAST_ADD_TIME_INVALID(vq); > + > + END_USE(vq); > + return ret; > +} > + > static void *virtqueue_get_buf_ctx_packed(struct vring_virtqueue *vq, > unsigned int *len, > void **ctx) > { > + unsigned int num = vq->packed.vring.num; > u16 last_used, id, last_used_idx; > bool used_wrap_counter; > void *ret; > @@ -1813,7 +2143,7 @@ static void *virtqueue_get_buf_ctx_packed(struct vring_virtqueue *vq, > return NULL; > } > > - if (!more_used_packed(vq)) { > + if (!__more_used_packed(vq)) { > pr_debug("No more buffers in queue\n"); > END_USE(vq); > return NULL; > @@ -1828,7 +2158,7 @@ static void *virtqueue_get_buf_ctx_packed(struct vring_virtqueue *vq, > id = le16_to_cpu(vq->packed.vring.desc[last_used].id); > *len = le32_to_cpu(vq->packed.vring.desc[last_used].len); > > - if (unlikely(id >= vq->packed.vring.num)) { > + if (unlikely(id >= num)) { > BAD_RING(vq, "id %u out of range\n", id); > return NULL; > } > @@ -1948,6 +2278,7 @@ static bool virtqueue_enable_cb_delayed_packed(struct vring_virtqueue *vq) > last_used_idx = READ_ONCE(vq->last_used_idx); > wrap_counter = packed_used_wrap_counter(last_used_idx); > used_idx = packed_last_used(last_used_idx); > + > if (is_used_desc_packed(vq, used_idx, wrap_counter)) { > END_USE(vq); > return false; > @@ -1969,7 +2300,7 @@ static void *virtqueue_detach_unused_buf_packed(struct vring_virtqueue *vq) > continue; > /* detach_buf clears data, so grab it now. */ > buf = vq->packed.desc_state[i].data; > - detach_buf_packed(vq, i, NULL); > + detach_buf_packed_in_order(vq, i, NULL); > END_USE(vq); > return buf; > } > @@ -1995,6 +2326,8 @@ static struct vring_desc_extra *vring_alloc_desc_extra(unsigned int num) > for (i = 0; i < num - 1; i++) > desc_extra[i].next = i + 1; > > + desc_extra[num - 1].next = 0; > + > return desc_extra; > } > > @@ -2126,8 +2459,12 @@ static void virtqueue_vring_attach_packed(struct vring_virtqueue *vq, > { > vq->packed = *vring_packed; > > - /* Put everything in free lists. */ > - vq->free_head = 0; > + if (virtqueue_is_in_order(vq)) > + vq->batch_head = vq->split.vring.num; > + else { > + /* Put everything in free lists. */ > + vq->free_head = 0; > + } > } > > static void virtqueue_reset_packed(struct vring_virtqueue *vq) > @@ -2174,13 +2511,14 @@ static struct virtqueue *__vring_new_virtqueue_packed(unsigned int index, > #else > vq->broken = false; > #endif > - vq->layout = PACKED; > vq->dma_dev = dma_dev; > vq->use_dma_api = vring_use_dma_api(vdev); > > vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC) && > !context; > vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX); > + vq->layout = virtio_has_feature(vdev, VIRTIO_F_IN_ORDER) ? > + PACKED_IN_ORDER : PACKED; > > if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM)) > vq->weak_barriers = false; > @@ -2290,9 +2628,39 @@ static const struct virtqueue_ops packed_ops = { > .reset = virtqueue_reset_packed, > }; > > +static const struct virtqueue_ops split_in_order_ops = { > + .add = virtqueue_add_split, > + .get = virtqueue_get_buf_ctx_split_in_order, > + .kick_prepare = virtqueue_kick_prepare_split, > + .disable_cb = virtqueue_disable_cb_split, > + .enable_cb_delayed = virtqueue_enable_cb_delayed_split, > + .enable_cb_prepare = virtqueue_enable_cb_prepare_split, > + .poll = virtqueue_poll_split, > + .detach_unused_buf = virtqueue_detach_unused_buf_split, > + .more_used = more_used_split_in_order, > + .resize = virtqueue_resize_split, > + .reset = virtqueue_reset_split, > +}; > + > +static const struct virtqueue_ops packed_in_order_ops = { > + .add = virtqueue_add_packed_in_order, > + .get = virtqueue_get_buf_ctx_packed_in_order, > + .kick_prepare = virtqueue_kick_prepare_packed, > + .disable_cb = virtqueue_disable_cb_packed, > + .enable_cb_delayed = virtqueue_enable_cb_delayed_packed, > + .enable_cb_prepare = virtqueue_enable_cb_prepare_packed, > + .poll = virtqueue_poll_packed, > + .detach_unused_buf = virtqueue_detach_unused_buf_packed, > + .more_used = more_used_packed_in_order, > + .resize = virtqueue_resize_packed, > + .reset = virtqueue_reset_packed, > +}; > + > static const struct virtqueue_ops *const all_ops[VQ_TYPE_MAX] = { > [SPLIT] = &split_ops, > - [PACKED] = &packed_ops > + [PACKED] = &packed_ops, > + [SPLIT_IN_ORDER] = &split_in_order_ops, > + [PACKED_IN_ORDER] = &packed_in_order_ops, > }; > > static int virtqueue_disable_and_recycle(struct virtqueue *_vq, > @@ -2336,7 +2704,6 @@ static int virtqueue_enable_after_reset(struct virtqueue *_vq) > /* > * Generic functions and exported symbols. > */ > - > #define VIRTQUEUE_CALL(vq, op, ...) \ > ({ \ > typeof(all_ops[SPLIT]->op(vq, ##__VA_ARGS__)) ret; \ > @@ -2347,6 +2714,12 @@ static int virtqueue_enable_after_reset(struct virtqueue *_vq) > case PACKED: \ > ret = all_ops[PACKED]->op(vq, ##__VA_ARGS__); \ > break; \ > + case SPLIT_IN_ORDER: \ > + ret = all_ops[SPLIT_IN_ORDER]->op(vq, ##__VA_ARGS__); \ > + break; \ > + case PACKED_IN_ORDER: \ > + ret = all_ops[PACKED_IN_ORDER]->op(vq, ##__VA_ARGS__); \ > + break; \ > default: \ > BUG(); \ > break; \ > @@ -2363,6 +2736,12 @@ static int virtqueue_enable_after_reset(struct virtqueue *_vq) > case PACKED: \ > all_ops[PACKED]->op(vq, ##__VA_ARGS__); \ > break; \ > + case SPLIT_IN_ORDER: \ > + all_ops[SPLIT_IN_ORDER]->op(vq, ##__VA_ARGS__); \ > + break; \ > + case PACKED_IN_ORDER: \ > + all_ops[PACKED_IN_ORDER]->op(vq, ##__VA_ARGS__); \ > + break; \ > default: \ > BUG(); \ > break; \ > @@ -3073,6 +3452,8 @@ void vring_transport_features(struct virtio_device *vdev) > break; > case VIRTIO_F_NOTIFICATION_DATA: > break; > + case VIRTIO_F_IN_ORDER: > + break; > default: > /* We don't understand this bit. */ > __virtio_clear_bit(vdev, i); > -- > 2.34.1