From: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
To: virtualization@lists.linux-foundation.org
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
Jason Wang <jasowang@redhat.com>,
Xuan Zhuo <xuanzhuo@linux.alibaba.com>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Jesper Dangaard Brouer <hawk@kernel.org>,
John Fastabend <john.fastabend@gmail.com>,
netdev@vger.kernel.org, bpf@vger.kernel.org,
Christoph Hellwig <hch@infradead.org>
Subject: [PATCH vhost v12 00/10] virtio core prepares for AF_XDP
Date: Wed, 19 Jul 2023 12:04:12 +0800 [thread overview]
Message-ID: <20230719040422.126357-1-xuanzhuo@linux.alibaba.com> (raw)
## About DMA APIs
Now, virtio may can not work with DMA APIs when virtio features do not have
VIRTIO_F_ACCESS_PLATFORM.
1. I tried to let DMA APIs return phy address by virtio-device. But DMA APIs just
work with the "real" devices.
2. I tried to let xsk support callballs to get phy address from virtio-net
driver as the dma address. But the maintainers of xsk may want to use dma-buf
to replace the DMA APIs. I think that may be a larger effort. We will wait
too long.
So rethinking this, firstly, we can support premapped-dma only for devices with
VIRTIO_F_ACCESS_PLATFORM. In the case of af-xdp, if the users want to use it,
they have to update the device to support VIRTIO_F_RING_RESET, and they can also
enable the device's VIRTIO_F_ACCESS_PLATFORM feature.
Thanks for the help from Christoph.
## For AF_XDP
XDP socket(AF_XDP) is an excellent bypass kernel network framework. The zero
copy feature of xsk (XDP socket) needs to be supported by the driver. The
performance of zero copy is very good.
ENV: Qemu with vhost.
vhost cpu | Guest APP CPU |Guest Softirq CPU | PPS
-----------------------------|---------------|------------------|------------
xmit by sockperf: 90% | 100% | | 318967
xmit by xsk: 100% | 30% | 33% | 1192064
recv by sockperf: 100% | 68% | 100% | 692288
recv by xsk: 100% | 33% | 43% | 771670
Before achieving the function of Virtio-Net, we also have to let virtio core
support these features:
1. virtio core support premapped
2. virtio core support reset per-queue
## VirtioNET rx dma merge
After introducing premapping, I added an example to virtio-net. virtio-net can
merge dma mappings through this feature. @Jason
kernel command line: intel_iommu=on iommu.passthrough=0
| strict=0 | strict=1
Before | 775496pps | 428614pps
After | 1109316pps | 742853pps
Please review.
Thanks.
v12:
1. Alloc dma info from the alloc frag. Avoid alloc array to store the dma info.
2. rename virtqueue_set_premapped() to virtqueue_set_dma_premapped()
v11
1. virtio-net merges dma operates based on the feature premapped
2. A better way to handle the map error with the premapped
v10:
1. support to set vq to premapped mode, then the vq just handles the premapped request.
2. virtio-net support to do dma mapping in advance
v9:
1. use flag to distinguish the premapped operations. no do judgment by sg.
v8:
1. vring_sg_address: check by sg_page(sg) not dma_address. Because 0 is a valid dma address
2. remove unused code from vring_map_one_sg()
v7:
1. virtqueue_dma_dev() return NULL when virtio is without DMA API.
v6:
1. change the size of the flags to u32.
v5:
1. fix for error handler
2. add flags to record internal dma mapping
v4:
1. rename map_inter to dma_map_internal
2. fix: Excess function parameter 'vq' description in 'virtqueue_dma_dev'
v3:
1. add map_inter to struct desc state to reocrd whether virtio core do dma map
v2:
1. based on sgs[0]->dma_address to judgment is premapped
2. based on extra.addr to judgment to do unmap for no-indirect desc
3. based on indir_desc to judgment to do unmap for indirect desc
4. rename virtqueue_get_dma_dev to virtqueue_dma_dev
v1:
1. expose dma device. NO introduce the api for dma and sync
2. split some commit for review.
Xuan Zhuo (10):
virtio_ring: check use_dma_api before unmap desc for indirect
virtio_ring: put mapping error check in vring_map_one_sg
virtio_ring: introduce virtqueue_set_dma_premapped()
virtio_ring: support add premapped buf
virtio_ring: introduce virtqueue_dma_dev()
virtio_ring: skip unmap for premapped
virtio_ring: correct the expression of the description of
virtqueue_resize()
virtio_ring: separate the logic of reset/enable from virtqueue_resize
virtio_ring: introduce virtqueue_reset()
virtio_net: merge dma operations when filling mergeable buffers
drivers/net/virtio_net.c | 225 +++++++++++++++++++++++++----
drivers/virtio/virtio_ring.c | 265 ++++++++++++++++++++++++++++-------
include/linux/virtio.h | 6 +
3 files changed, 418 insertions(+), 78 deletions(-)
--
2.32.0.3.g01195cf9f
next reply other threads:[~2023-07-19 4:04 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-19 4:04 Xuan Zhuo [this message]
2023-07-19 4:04 ` [PATCH vhost v12 01/10] virtio_ring: check use_dma_api before unmap desc for indirect Xuan Zhuo
2023-07-19 4:04 ` [PATCH vhost v12 02/10] virtio_ring: put mapping error check in vring_map_one_sg Xuan Zhuo
2023-07-19 4:04 ` [PATCH vhost v12 03/10] virtio_ring: introduce virtqueue_set_dma_premapped() Xuan Zhuo
2023-07-19 4:04 ` [PATCH vhost v12 04/10] virtio_ring: support add premapped buf Xuan Zhuo
2023-07-19 4:04 ` [PATCH vhost v12 05/10] virtio_ring: introduce virtqueue_dma_dev() Xuan Zhuo
2023-07-19 4:04 ` [PATCH vhost v12 06/10] virtio_ring: skip unmap for premapped Xuan Zhuo
2023-07-19 4:04 ` [PATCH vhost v12 07/10] virtio_ring: correct the expression of the description of virtqueue_resize() Xuan Zhuo
2023-07-19 4:04 ` [PATCH vhost v12 08/10] virtio_ring: separate the logic of reset/enable from virtqueue_resize Xuan Zhuo
2023-07-19 4:04 ` [PATCH vhost v12 09/10] virtio_ring: introduce virtqueue_reset() Xuan Zhuo
2023-07-19 4:04 ` [PATCH vhost v12 10/10] virtio_net: merge dma operations when filling mergeable buffers Xuan Zhuo
2023-07-19 10:33 ` kernel test robot
2023-07-19 11:05 ` Michael S. Tsirkin
2023-07-20 2:31 ` Xuan Zhuo
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