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Re: [PATCH RFC v2 00/12] virtio-net: add support for SR-IOV emulation
From: |
Jason Wang |
Subject: |
Re: [PATCH RFC v2 00/12] virtio-net: add support for SR-IOV emulation |
Date: |
Mon, 11 Dec 2023 10:52:41 +0800 |
On Sun, Dec 10, 2023 at 12:06 PM Akihiko Odaki <akihiko.odaki@daynix.com> wrote:
>
> Introduction
> ------------
>
> This series is based on the RFC series submitted by Yui Washizu[1].
> See also [2] for the context.
>
> This series enables SR-IOV emulation for virtio-net. It is useful
> to test SR-IOV support on the guest, or to expose several vDPA devices
> in a VM. vDPA devices can also provide L2 switching feature for
> offloading though it is out of scope to allow the guest to configure
> such a feature.
>
> The PF side code resides in virtio-pci. The VF side code resides in
> the PCI common infrastructure, but it is restricted to work only for
> virtio-net-pci because of lack of validation.
>
> User Interface
> --------------
>
> A user can configure a SR-IOV capable virtio-net device by adding
> virtio-net-pci functions to a bus. Below is a command line example:
> -netdev user,id=n -netdev user,id=o
> -netdev user,id=p -netdev user,id=q
> -device pcie-root-port,id=b
> -device virtio-net-pci,bus=b,addr=0x0.0x3,netdev=q,sriov-pf=f
> -device virtio-net-pci,bus=b,addr=0x0.0x2,netdev=p,sriov-pf=f
> -device virtio-net-pci,bus=b,addr=0x0.0x1,netdev=o,sriov-pf=f
> -device virtio-net-pci,bus=b,addr=0x0.0x0,netdev=n,id=f
>
> The VFs specify the paired PF with "sriov-pf" property. The PF must be
> added after all VFs. It is user's responsibility to ensure that VFs have
> function numbers larger than one of the PF, and the function numbers
> have a consistent stride.
This seems not user friendly. Any reason we can't just allow user to
specify the stride here?
Btw, I vaguely remember qemu allows the params to be accepted as a
list. If this is true, we can accept a list of netdev here?
>
> Keeping VF instances
> --------------------
>
> A problem with SR-IOV emulation is that it needs to hotplug the VFs as
> the guest requests. Previously, this behavior was implemented by
> realizing and unrealizing VFs at runtime. However, this strategy does
> not work well for the proposed virtio-net emulation; in this proposal,
> device options passed in the command line must be maintained as VFs
> are hotplugged, but they are consumed when the machine starts and not
> available after that, which makes realizing VFs at runtime impossible.
Could we store the device options in the PF?
Thanks
>
> As an strategy alternative to runtime realization/unrealization, this
> series proposes to reuse the code to power down PCI Express devices.
> When a PCI Express device is powered down, it will be hidden from the
> guest but will be kept realized. This effectively implements the
> behavior we need for the SR-IOV emulation.
>
> Summary
> -------
>
> Patch [1, 5] refactors the PCI infrastructure code.
> Patch [6, 10] adds user-created SR-IOV VF infrastructure.
> Patch 11 makes virtio-pci work as SR-IOV PF for user-created VFs.
> Patch 12 allows user to create SR-IOV VFs with virtio-net-pci.
>
> [1]
> https://patchew.org/QEMU/1689731808-3009-1-git-send-email-yui.washidu@gmail.com/
> [2]
> https://lore.kernel.org/all/5d46f455-f530-4e5e-9ae7-13a2297d4bc5@daynix.com/
>
> Co-developed-by: Yui Washizu <yui.washidu@gmail.com>
> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
> ---
> Changes in v2:
> - Changed to keep VF instances.
> - Link to v1:
> 20231202-sriov-v1-0-32b3570f7bd6@daynix.com">https://lore.kernel.org/r/20231202-sriov-v1-0-32b3570f7bd6@daynix.com
>
> ---
> Akihiko Odaki (12):
> hw/pci: Initialize PCI multifunction after realization
> hw/pci: Determine if rombar is explicitly enabled
> hw/pci: Do not add ROM BAR for SR-IOV VF
> vfio: Avoid inspecting option QDict for rombar
> hw/qdev: Remove opts member
> pcie_sriov: Reuse SR-IOV VF device instances
> pcie_sriov: Release VFs failed to realize
> pcie_sriov: Ensure PF and VF are mutually exclusive
> pcie_sriov: Check PCI Express for SR-IOV PF
> pcie_sriov: Allow user to create SR-IOV device
> virtio-pci: Implement SR-IOV PF
> virtio-net: Implement SR-IOV VF
>
> docs/pcie_sriov.txt | 8 +-
> include/hw/pci/pci.h | 2 +-
> include/hw/pci/pci_device.h | 13 +-
> include/hw/pci/pcie_sriov.h | 25 ++-
> include/hw/qdev-core.h | 4 -
> hw/core/qdev.c | 1 -
> hw/net/igb.c | 3 +-
> hw/nvme/ctrl.c | 3 +-
> hw/pci/pci.c | 98 +++++++-----
> hw/pci/pci_host.c | 4 +-
> hw/pci/pcie.c | 4 +-
> hw/pci/pcie_sriov.c | 360
> +++++++++++++++++++++++++++++++++-----------
> hw/vfio/pci.c | 3 +-
> hw/virtio/virtio-net-pci.c | 1 +
> hw/virtio/virtio-pci.c | 7 +
> system/qdev-monitor.c | 12 +-
> 16 files changed, 395 insertions(+), 153 deletions(-)
> ---
> base-commit: 4705fc0c8511d073bee4751c3c974aab2b10a970
> change-id: 20231202-sriov-9402fb262be8
>
> Best regards,
> --
> Akihiko Odaki <akihiko.odaki@daynix.com>
>
- [PATCH RFC v2 05/12] hw/qdev: Remove opts member, (continued)
- [PATCH RFC v2 05/12] hw/qdev: Remove opts member, Akihiko Odaki, 2023/12/09
- [PATCH RFC v2 06/12] pcie_sriov: Reuse SR-IOV VF device instances, Akihiko Odaki, 2023/12/09
- [PATCH RFC v2 07/12] pcie_sriov: Release VFs failed to realize, Akihiko Odaki, 2023/12/09
- [PATCH RFC v2 08/12] pcie_sriov: Ensure PF and VF are mutually exclusive, Akihiko Odaki, 2023/12/09
- [PATCH RFC v2 09/12] pcie_sriov: Check PCI Express for SR-IOV PF, Akihiko Odaki, 2023/12/09
- [PATCH RFC v2 10/12] pcie_sriov: Allow user to create SR-IOV device, Akihiko Odaki, 2023/12/09
- [PATCH RFC v2 11/12] virtio-pci: Implement SR-IOV PF, Akihiko Odaki, 2023/12/09
- [PATCH RFC v2 12/12] virtio-net: Implement SR-IOV VF, Akihiko Odaki, 2023/12/09
- Re: [PATCH RFC v2 00/12] virtio-net: add support for SR-IOV emulation,
Jason Wang <=
Re: [PATCH RFC v2 00/12] virtio-net: add support for SR-IOV emulation, Yui Washizu, 2023/12/19