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

Liu Yi L
2019-09-06T08:17:26Z

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

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2.7.4