Re: [PATCH v5 00/15] Support VIRTIO_F_RING_RESET for virtio-net, vhost-net kernel in virtio pci-modern

[Michael S. Tsirkin]

On Wed, Sep 14, 2022 at 12:20:40PM +0800, Xuan Zhuo wrote:
> The virtio queue reset function has already been defined in the virtio spec 
> 1.2.
> The relevant virtio spec information is here:
> 
>     https://github.com/oasis-tcs/virtio-spec/issues/124
>     https://github.com/oasis-tcs/virtio-spec/issues/139
> 
> This patch set is to support this function in QEMU. It consists of several 
> parts:
> 1. Patches 1-7 are the basic interfaces for vq reset in virtio and virtio-pci.
> 2. Patches 8-11 support vq reset and vq restart for vhost-kernel.
> 3. Patches 12-14 support vq reset and vq restart for virtio-net.
> 5. Patch 15 enables the vq reset feature for vhost-kernel.
> 
> The process of virtqueue reset can be concluded as:
> 1. The virtqueue is disabled when VIRTIO_PCI_COMMON_Q_RESET is written.
> 2. Then the virtqueue can be optionally restarted(re-enabled).
> 
> Since this patch set involves multiple modules and seems a bit messy, we 
> briefly describe the
> calling process for different modes below.
> virtio-net:
> 1. VIRTIO_PCI_COMMON_Q_RESET is written [virtio-pci]
>     -> virtio_queue_reset() [virtio]
>         -> virtio_net_queue_reset() [virtio-net]
>         -> __virtio_queue_reset()
> 2. VIRTIO_PCI_COMMON_Q_ENABLE is written [virtio-pci]
>     -> set enabled, reset status of vq.
> 
> vhost-kernel:
> 1. VIRTIO_PCI_COMMON_Q_RESET is written [virtio-pci]
>     -> virtio_queue_reset() [virtio]
>         -> virtio_net_queue_reset() [virtio-net]
>             -> vhost_net_virtqueue_stop() [vhost-net]
>                 -> vhost_net_set_backend() [vhost]
>                 -> vhost_virtqueue_stop()
>         -> __virtio_queue_reset()
> 2. VIRTIO_PCI_COMMON_Q_ENABLE is written [virtio-pci]
>     -> virtio_queue_enable() [virtio]
>         -> virtio_net_queue_enable() [virtio-net]
>             -> vhost_net_virtqueue_restart() [vhost-net]
>                 -> vhost_virtqueue_start() [vhost]
>                 -> vhost_net_set_backend()
>     -> set enabled, reset status of vq.
> 
> 
> Test environment and method:
>     Host: 5.19.0-rc3 (With vq reset support)
>     Qemu: QEMU emulator version 7.0.50
>     Guest: 5.19.0-rc3 (With vq reset support)
>     Test Cmd: ethtool -g eth1; ethtool -G eth1 rx $1 tx $2; ethtool -g eth1;
> 
>     The drvier can resize the virtio queue, then virtio queue reset function 
> should
>     be triggered.
> 
>     The default is split mode, modify Qemu virtio-net to add PACKED feature to
>     test packed mode.
> 
> Guest Kernel Patch:
>     
> https://lore.kernel.org/bpf/20220801063902.129329-1-xuanzhuo@linux.alibaba.com/
> 
> Host Kernel Patch:
>     
> https://lore.kernel.org/bpf/20220825085610.80315-1-kangjie.xu@linux.alibaba.com/
> 
> Looking forward to your review and comments. Thanks.

Breaks mingw 32 build

Wl,--no-seh -Wl,--nxcompat -Wl,--warn-common libqemuutil.a libfdt.a 
libmigration.fa libhwcore.fa libqom.fa libio.fa libcrypto.fa libauthz.fa 
libblockdev.fa libblock.fa libchardev.fa libqmp.fa @block.syms @qemu.syms 
/usr/i686-w64-mingw32/sys-root/mingw/lib/libpixman-1.dll.a 
/usr/i686-w64-mingw32/sys-root/mingw/lib/libz.dll.a -lole32 -ldxguid 
/usr/i686-w64-mingw32/sys-root/mingw/lib/libmingw32.a -mwindows 
/usr/i686-w64-mingw32/sys-root/mingw/lib/libSDL2main.a 
/usr/i686-w64-mingw32/sys-root/mingw/lib/libSDL2.dll.a 
/usr/i686-w64-mingw32/sys-root/mingw/lib/libgio-2.0.dll.a 
/usr/i686-w64-mingw32/sys-root/mingw/lib/libgobject-2.0.dll.a 
/usr/i686-w64-mingw32/sys-root/mingw/lib/libglib-2.0.dll.a 
/usr/i686-w64-mingw32/sys-root/mingw/lib/libintl.dll.a -lgthread-2.0 -lglib-2.0 
-lintl @block.syms -lwinmm -lpathcch -lm -pthread -lgthread-2.0 -lglib-2.0 
-lintl -lws2_32 -Wl,--subsystem,console -lkernel32 -luser32 -lgdi32 -lwinspool 
-lshell32 -loleaut32 -luuid -lcomdlg32 -ladvapi32 -lstdc++ -Wl,--end-group
/usr/lib/gcc/i686-w64-mingw32/11.2.1/../../../../i686-w64-mingw32/bin/ld: 
libqemu-alpha-softmmu.fa.p/hw_net_virtio-net.c.obj: in function 
`virtio_net_queue_reset':
/scm/qemu-mingw32-build/../qemu/hw/net/virtio-net.c:560: undefined reference to 
`vhost_net_virtqueue_reset'
/usr/lib/gcc/i686-w64-mingw32/11.2.1/../../../../i686-w64-mingw32/bin/ld: 
libqemu-alpha-softmmu.fa.p/hw_net_virtio-net.c.obj: in function 
`virtio_net_queue_enable':
/scm/qemu-mingw32-build/../qemu/hw/net/virtio-net.c:578: undefined reference to 
`vhost_net_virtqueue_restart'
collect2: error: ld returned 1 exit status




> changelog:
> 
> v5:
>   1. vhost_net_virtqueue_restart() use -EBUSY replace -ENOTSUP. @Jason
>   2. reuse  VHOST_FILE_UNBIND. @Jason
> 
> v4:
>   1. Add explanation for preventing userspace datapath in virtio-net.
>   2. Return error when vhost is not started in vhost_net_virtqueue_restart().
>   3. Reset the virtqueue in the device reusing vhost_virtqueue_stop().
>   4. Disable queue reset feature for pre-7.2 machine.
> 
> v3:
>   1. Remove support for vhost-user in this series and refactor the code.
>   2. Rename 'vhost_net_virtqueue_stop' to 'vhost_net_virtqueue_reset'.
>   3. Make PCI transport ready before device ready when queue_enabled is set 
> to true.
>   4. Add some comments.
> 
> v2:
>   1. Add support for vhost-net kernel scenario.
>   2. Add a new vhost-user message VHOST_USER_RESET_VRING.
>   3. Add migration compatibility for virtqueue reset.
> 
> Kangjie Xu (10):
>   virtio: introduce virtio_queue_enable()
>   virtio: core: vq reset feature negotation support
>   virtio-pci: support queue enable
>   vhost: expose vhost_virtqueue_start()
>   vhost: expose vhost_virtqueue_stop()
>   vhost-net: vhost-kernel: introduce vhost_net_virtqueue_reset()
>   vhost-net: vhost-kernel: introduce vhost_net_virtqueue_restart()
>   virtio-net: introduce flush_or_purge_queued_packets()
>   virtio-net: support queue_enable
>   vhost: vhost-kernel: enable vq reset feature
> 
> Xuan Zhuo (5):
>   virtio: sync relevant definitions with linux
>   virtio: introduce __virtio_queue_reset()
>   virtio: introduce virtio_queue_reset()
>   virtio-pci: support queue reset
>   virtio-net: support queue reset
> 
>  hw/core/machine.c                             |  4 +-
>  hw/net/vhost_net.c                            | 79 +++++++++++++++++++
>  hw/net/virtio-net.c                           | 56 +++++++++++--
>  hw/virtio/vhost.c                             | 16 ++--
>  hw/virtio/virtio-pci.c                        | 16 ++++
>  hw/virtio/virtio.c                            | 62 +++++++++++----
>  include/hw/virtio/vhost.h                     |  5 ++
>  include/hw/virtio/virtio-pci.h                |  5 ++
>  include/hw/virtio/virtio.h                    |  8 +-
>  include/net/vhost_net.h                       |  4 +
>  .../standard-headers/linux/virtio_config.h    |  5 ++
>  include/standard-headers/linux/virtio_pci.h   |  2 +
>  12 files changed, 230 insertions(+), 32 deletions(-)
> 
> --
> 2.32.0.3.g01195cf9f