Re: [GIT PULL] virtio: features
From: Xuan Zhuo
Date: Tue Sep 26 2023 - 22:30:48 EST
On Tue, 26 Sep 2023 08:04:51 -0500, Michael Roth <michael.roth@xxxxxxx> wrote:
> On Sun, Sep 03, 2023 at 06:13:38PM -0400, Michael S. Tsirkin wrote:
> > The following changes since commit 2dde18cd1d8fac735875f2e4987f11817cc0bc2c:
> >
> > Linux 6.5 (2023-08-27 14:49:51 -0700)
> >
> > are available in the Git repository at:
> >
> > https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git tags/for_linus
> >
> > for you to fetch changes up to 1acfe2c1225899eab5ab724c91b7e1eb2881b9ab:
> >
> > virtio_ring: fix avail_wrap_counter in virtqueue_add_packed (2023-09-03 18:10:24 -0400)
> >
> > ----------------------------------------------------------------
> > virtio: features
> >
> > a small pull request this time around, mostly because the
> > vduse network got postponed to next relase so we can be sure
> > we got the security store right.
> >
> > Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> >
> > ----------------------------------------------------------------
> > Eugenio P閞ez (4):
> > vdpa: add VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK flag
> > vdpa: accept VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK backend feature
> > vdpa: add get_backend_features vdpa operation
> > vdpa_sim: offer VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK
> >
> > Jason Wang (1):
> > virtio_vdpa: build affinity masks conditionally
> >
> > Xuan Zhuo (12):
> > 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_ring: introduce dma map api for virtqueue
> > virtio_ring: introduce dma sync api for virtqueue
> > virtio_net: merge dma operations when filling mergeable buffers
>
> This ^ patch (upstream commit 295525e29a) seems to cause a
> network-related regression when using SWIOTLB in the guest. I noticed
> this initially testing SEV guests, which use SWIOTLB by default, but
> it can also be seen with normal guests when forcing SWIOTLB via
> swiotlb=force kernel cmdline option. I see it with both 6.6-rc1 and
> 6.6-rc2 (haven't tried rc3 yet, but don't see any related changes
> there), and reverting 714073495f seems to avoid the issue.
>
> Steps to reproduce:
>
> 1) Boot QEMU/KVM guest with 6.6-rc2 with swiotlb=force via something like the following cmdline:
>
> qemu-system-x86_64 \
> -machine q35 -smp 4,maxcpus=255 -cpu EPYC-Milan-v2 \
> -enable-kvm -m 16G,slots=5,maxmem=256G -vga none \
> -device virtio-scsi-pci,id=scsi0,disable-legacy=on,iommu_platform=true \
> -drive file=/home/mroth/storage/ubuntu-18.04-seves2.qcow2,if=none,id=drive0,snapshot=off \
> -device scsi-hd,id=hd0,drive=drive0,bus=scsi0.0 \
> -device virtio-net-pci,netdev=netdev0,id=net0,disable-legacy=on,iommu_platform=true,romfile= \
> -netdev tap,script=/home/mroth/qemu-ifup,id=netdev0 \
> -L /home/mroth/storage/AMDSEV2/snp-release-2023-09-23/usr/local/share/qemu \
> -drive if=pflash,format=raw,unit=0,file=/home/mroth/storage/AMDSEV2/snp-release-2023-09-23/usr/local/share/qemu/OVMF_CODE.fd,readonly \
> -drive if=pflash,format=raw,unit=1,file=/home/mroth/storage/AMDSEV2/snp-release-2023-09-23/usr/local/share/qemu/OVMF_VARS.fd \
> -debugcon file:debug.log -global isa-debugcon.iobase=0x402 -msg timestamp=on \
> -kernel /boot/vmlinuz-6.6.0-rc2-vanilla0+ \
> -initrd /boot/initrd.img-6.6.0-rc2-vanilla0+ \
> -append "root=UUID=d72a6d1c-06cf-4b79-af43-f1bac4f620f9 ro console=ttyS0,115200n8 earlyprintk=serial,ttyS0,115200 debug=1 sev=debug page_poison=0 spec_rstack_overflow=off swiotlb=force"
>
> 2) scp a small file from the host to the guest IP via its virtio-net device.
> Smaller file sizes succeed, but the larger the file the more likely
> it will fail. e.g.:
>
> mroth@host:~$ dd if=/dev/zero of=test bs=1K count=19
> 19+0 records in
> 19+0 records out
> 19456 bytes (19 kB, 19 KiB) copied, 0.000940134 s, 20.7 MB/s
> mroth@host:~$ scp test vm0:
> test 100% 19KB 10.1MB/s 00:00
> mroth@host:~$ dd if=/dev/zero of=test bs=1K count=20
> 20+0 records in
> 20+0 records out
> 20480 bytes (20 kB, 20 KiB) copied, 0.00093774 s, 21.8 MB/s
> mroth@host:~$ scp test vm0:
> test 0% 0 0.0KB/s --:-- ETA
> client_loop: send disconnect: Broken pipe
> lost connection
> mroth@host:~$
Hi Michael,
Thanks for the report.
Cloud you try this fix? I reproduce this issue, and that works for me.
Thanks.
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 98dc9b49d56b..9ece27dc5144 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -589,16 +589,16 @@ static void virtnet_rq_unmap(struct receive_queue *rq, void *buf, u32 len)
--dma->ref;
- if (dma->ref) {
- if (dma->need_sync && len) {
- offset = buf - (head + sizeof(*dma));
+ if (dma->need_sync && len) {
+ offset = buf - (head + sizeof(*dma));
- virtqueue_dma_sync_single_range_for_cpu(rq->vq, dma->addr, offset,
- len, DMA_FROM_DEVICE);
- }
+ virtqueue_dma_sync_single_range_for_cpu(rq->vq, dma->addr,
+ offset, len,
+ DMA_FROM_DEVICE);
+ }
+ if (dma->ref)
return;
- }
virtqueue_dma_unmap_single_attrs(rq->vq, dma->addr, dma->len,
DMA_FROM_DEVICE, DMA_ATTR_SKIP_CPU_SYNC);
>
> Thanks,
>
> Mike
>
> >
> > Yuan Yao (1):
> > virtio_ring: fix avail_wrap_counter in virtqueue_add_packed
> >
> > Yue Haibing (1):
> > vdpa/mlx5: Remove unused function declarations
> >
> > drivers/net/virtio_net.c | 230 ++++++++++++++++++---
> > drivers/vdpa/mlx5/core/mlx5_vdpa.h | 3 -
> > drivers/vdpa/vdpa_sim/vdpa_sim.c | 8 +
> > drivers/vhost/vdpa.c | 15 +-
> > drivers/virtio/virtio_ring.c | 412 ++++++++++++++++++++++++++++++++-----
> > drivers/virtio/virtio_vdpa.c | 17 +-
> > include/linux/vdpa.h | 4 +
> > include/linux/virtio.h | 22 ++
> > include/uapi/linux/vhost_types.h | 4 +
> > 9 files changed, 625 insertions(+), 90 deletions(-)
> >