RE: [PATCH v2 00/13] vfio_pci: wrap pci device as a mediated device

Liu, Yi L
2019-09-25T09:15:04Z

Hi Alex,

Any comments on it? :-) With this version, the vfio-mdev-pci driver
could work with non-singleton groups, also it works with vfio-pci
as well.

Regards,
Yi Liu

> From: Liu, Yi L
> Sent: Thursday, September 5, 2019 3:59 PM
> To: alex.williamson@redhat.com; kwankhede@nvidia.com
> Subject: [PATCH v2 00/13] vfio_pci: wrap pci device as a mediated device
>
> This patchset aims to add a vfio-pci-like meta driver as a demo
> user of the vfio changes introduced in "vfio/mdev: IOMMU aware
> mediated device" patchset from Baolu Lu. Besides the test purpose,
> per Alex's comments, it could also be a good base driver for
> experimenting with device specific mdev migration.
>
> Specific interface tested in this proposal:
> *) int mdev_set_iommu_device(struct device *dev,
> struct device *iommu_device)
> introduced in the patch as below:
> "[PATCH v5 6/8] vfio/mdev: Add iommu related member in mdev_device"
>
> Patch Overview:
> *) patch 1 ~ 7: code refactor for existing vfio-pci module
> move the common codes from vfio_pci.c to
> vfio_pci_common.c
> *) patch 8: add protection to perm_bits alloc/free
> *) patch 9: add vfio-mdev-pci sample driver
> *) patch 10: refine the sample driver
> *) patch 11 - 13: make the sample driver work for non-singleton groups
> also work for vfio-pci and vfio-mdev-pci mixed usage
> includes vfio-mdev-pci driver change and vfio_iommu_type1
> changes.
>
> Links:
> *) Link of "vfio/mdev: IOMMU aware mediated device"
> https://lwn.net/Articles/780522/
> *) Previous versions:
> RFC v1: https://lkml.org/lkml/2019/3/4/529
> RFC v2: https://lkml.org/lkml/2019/3/13/113
> RFC v3: https://lkml.org/lkml/2019/4/24/495
> Patch v1: https://www.spinics.net/lists/kvm/msg188952.html
> *) may try it with the codes in below repo
> current version is branch "v5.3-rc7-pci-mdev":
> https://github.com/luxis1999/vfio-mdev-pci-sample-driver.git
>
> Test done on two NICs which share an iommu group.
>
> -------------------------------------------------------------------
> | NIC0 | NIC1 | vIOMMU | VMs | Passtrhu
> -------------------------------------------------------------------
> Test#0 | vfio-pci | vfio-pci | no | 1 | pass
> -------------------------------------------------------------------
> Test#1 | vfio-pci | vfio-pci | no | 2 | fail[1]
> -------------------------------------------------------------------
> Test#2 | vfio-pci | vfio-pci | yes | 1 | fail[2]
> -------------------------------------------------------------------
> Test#3 | vfio-pci-mdev | vfio-pci | no | 1 | pass
> -------------------------------------------------------------------
> Test#4 | vfio-pci-mdev | vfio-pci | no | 2 | fail[3]
> -------------------------------------------------------------------
> Test#5 | vfio-pci-mdev | vfio-pci | yes | 1 | fail[4]
> -------------------------------------------------------------------
> Tips:
> [1] qemu-system-x86_64: -device vfio-pci,host=01:00.1,id=hostdev0,addr=0x6:
> vfio 0000:01:00.1: failed to open /dev/vfio/1: Device or resource busy
> [2] qemu-system-x86_64: -device vfio-pci,host=01:00.1,id=hostdev0,addr=0x6:
> vfio 0000:01:00.1: group 1 used in multiple address spaces
> [3] qemu-system-x86_64: -device vfio-pci,host=01:00.1,id=hostdev0,addr=0x6:
> vfio 0000:01:00.1: failed to setup container for group 1: Failed to set
> iommu for container: Device or resource busy
> [4] qemu-system-x86_64: -device vfio-pci,host=01:00.1,id=hostdev0,addr=0x6:
> vfio 0000:01:00.1: failed to setup container for group 1: Failed to set
> iommu for container: Device or resource busy
> Or
> qemu-system-x86_64: -device vfio-pci,sysfsdev=/sys/bus/mdev/devices/
> 83b8f4f2-509f-382f-3c1e-e6bfe0fa1003: vfio 83b8f4f2-509f-382f-3c1e-
> e6bfe0fa1003: failed to setup container for group 11: Failed to set iommu
> for container: Device or resource busy
> Some other tests are not listed. Like bind NIC0 to vfio-pci-mdev and try to
> passthru it with "vfio-pci,host=01:00.0", kernel will throw a warn log and
> fail the operation.
>
> Please feel free give your comments.
>
> Thanks,
> Yi Liu
>
> Change log:
> patch v1 -> patch v2:
> - the sample driver implementation refined
> - the sample driver can work on non-singleton iommu groups
> - the sample driver can work with vfio-pci, devices from a non-singleton
> group can either be bound to vfio-mdev-pci or vfio-pci, and the
> assignment of this group still follows current vfio assignment rule.
>
> RFC v3 -> patch v1:
> - split the patchset from 3 patches to 9 patches to better demonstrate
> the changes step by step
>
> v2->v3:
> - use vfio-mdev-pci instead of vfio-pci-mdev
> - place the new driver under drivers/vfio/pci while define
> Kconfig in samples/Kconfig to clarify it is a sample driver
>
> v1->v2:
> - instead of adding kernel option to existing vfio-pci
> module in v1, v2 follows Alex's suggestion to add a
> separate vfio-pci-mdev module.
> - new patchset subject: "vfio/pci: wrap pci device as a mediated device"
>
> Alex Williamson (1):
> samples: refine vfio-mdev-pci driver
>
> Liu Yi L (12):
> vfio_pci: move vfio_pci_is_vga/vfio_vga_disabled to header
> vfio_pci: refine user config reference in vfio-pci module
> vfio_pci: refine vfio_pci_driver reference in vfio_pci.c
> vfio_pci: make common functions be extern
> vfio_pci: duplicate vfio_pci.c
> vfio_pci: shrink vfio_pci_common.c
> vfio_pci: shrink vfio_pci.c
> vfio/pci: protect cap/ecap_perm bits alloc/free with atomic op
> samples: add vfio-mdev-pci driver
> samples/vfio-mdev-pci: call vfio_add_group_dev()
> vfio/type1: use iommu_attach_group() for wrapping PF/VF as mdev
> vfio/type1: track iommu backed group attach
>
> drivers/vfio/pci/Makefile | 9 +-
> drivers/vfio/pci/vfio_mdev_pci.c | 497 ++++++++++++
> drivers/vfio/pci/vfio_pci.c | 1449 +---------------------------------
> drivers/vfio/pci/vfio_pci_common.c | 1455
> +++++++++++++++++++++++++++++++++++
> drivers/vfio/pci/vfio_pci_config.c | 9 +
> drivers/vfio/pci/vfio_pci_private.h | 36 +
> drivers/vfio/vfio_iommu_type1.c | 185 ++++-
> samples/Kconfig | 11 +
> 8 files changed, 2194 insertions(+), 1457 deletions(-)
> create mode 100644 drivers/vfio/pci/vfio_mdev_pci.c
> create mode 100644 drivers/vfio/pci/vfio_pci_common.c
>
> --
> 2.7.4