Re: [PATCH v5 00/20] vfio/pci: Base Live Update support for VFIO

["Yanjun.Zhu" <yanjun.zhu@linux.dev>]

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On 7/14/26 8:14 AM, Vipin Sharma wrote:
> Hello,
>
> This series can be found on Github:
>
>    https://github.com/shvipin/linux vfio/liveupdate/v5
>
> This series provides the base support to enable Live Update feature for
> VFIO PCI devices using the Live Update Orchestrator (LUO) and Kexec
> Handover (KHO).
>
> Overview
> --------
>
> This series makes the following changes to support VFIO Live Update:
>
>   - Puts VFIO Live Update support behind the CONFIG_VFIO_PCI_LIVEUPDATE
>     config option (which requires CONFIG_VFIO_DEVICE_CDEV).
>   - Preserves VFIO cdev device FDs across a kexec Live Update session via
>     LUO/KHO.
>   - Enforces that incoming preserved devices can only be retrieved via
>     LIVEUPDATE_SESSION_RETRIEVE_FD post-kexec (preventing legacy
>     group/cdev opens from accessing uninitialized state).
>   - Quiesces the device prior to kexec in freeze() by resetting hardware,
>     disabling bus mastering, and marking the device frozen to reject
>     post-freeze IO/MMIO.
>   - Includes VFIO selftests (uapi & kexec tests with continuous DMA
>     checks) and kernel documentation.
>
> VFIO PCI Live Update Roadmap
> ----------------------------
>
> We are planning to add VFIO PCI Live Update support in phases. Since full
> support of this feature will come in phase, VFIO PCI Liveupdate is
> controlled by CONFIG_VFIO_PCI_LIVEUPDATE config option.
>
> This series is phase 1 below:
>
>   1. PCIe function (non-VF) preserved across Live Update without changing
>      BDF
>   2. PCIe function (non-VF) preserved across Live Update without resetting
>   3. PCIe function (non-VF) preserved across Live Update with continuous
>      DMA (noiommu)
>   4. PCIe function (non-VF) preserved across Live Update with continuous
>      DMA (iommufd)
>   5. PCIe VF preserved across Live Update with continuous DMA (iommufd)
>
> Dependencies
> ------------
>
> This series has following dependencies as shown in the diagram
>
>      |---------------------------|
>      |         VFIO v5           |  <--- Sent in this series.
>      |---------------------------|
>      |  Liveupdate Selftests[1]  |
>      |---------------------------|
>      |        PCI v7 [2]         |
>      |---------------------------|
>
> [1]https://lore.kernel.org/all/20260511201155.1488670-1-vipinsh@google.com/
>      These selftests changes are needed by other selftests also (iommu,
>      kvm), so, I have sent them separately.
>
> [2]https://lore.kernel.org/linux-pci/20260710212616.1351130-1-dmatlack@google.com/
>      This is the PCI v7, which adds the live update support in PCI core.
>
> Github branch I have mentioned at the top has all of these dependencies.
>
> Testing
> -------
>
> Tested using VFIO Live Update selftests in both QEMU and bare-metal
> environment (Intel DSA PCIe device).

I want to make tests VFIO Live Update selftests in QEMU. But how to 
select a PCIe device?

what device do the PCI ID 0000:00:04.0 and 0000:6a:01.0 mean in the 
following testcase?

Zhu Yanjun

>
>    $ ./setup.sh 0000:00:04.0
>    $ ./vfio_pci_liveupdate_kexec_test --stage 1 0000:6a:01.0
>    $ kexec --reuse-cmdline -l -s /boot/vmlinuz
>    $ kexec -e
>    $ ./setup.sh 0000:00:04.0
>    $ ./vfio_pci_liveupdate_kexec_test --stage 2 0000:6a:01.0
>
> Kernel command line options used:
>    - liveupdate=on
>    - kho=on
>    - vfio_iommu_type1.allow_unsafe_interrupts=Y
>    - vfio_pci.enable_sriov=Y
>    - vfio_pci.disable_denylist=Y
>    - vfio.enable_unsafe_noiommu_mode=Y
>
>
> Changelog
> ---------
>
> v5:
>   - Addressed Sashiko feedback.
>   - Removed condition to disable CONFIG_VFIO_PCI_DMABUF.
>   - Expanded vfio_find_device() helper to safely discover a registered
>     vfio_device by matching criteria. Internal Sashiko instance found
>     data race.
>   - Updated selftests to latest changes in VFIO selftests.
>   - Rebased on top of PCI Live Update series v7.
>
> v4:https://lore.kernel.org/kvm/20260511234802.2280368-1-vipinsh@google.com/
>
> v3:https://lore.kernel.org/kvm/20260323235817.1960573-1-dmatlack@google.com/
>
> v2:https://lore.kernel.org/kvm/20260129212510.967611-1-dmatlack@google.com/
>
> v1:https://lore.kernel.org/kvm/20251126193608.2678510-1-dmatlack@google.com/
>
> rfc:https://lore.kernel.org/kvm/20251018000713.677779-1-vipinsh@google.com/
>
>
> David Matlack (7):
>    vfio: Enforce preserved devices are retrieved via
>      LIVEUPDATE_SESSION_RETRIEVE_FD
>    docs: liveupdate: Add documentation for VFIO PCI
>    vfio: selftests: Add vfio_pci_liveupdate_uapi_test
>    vfio: selftests: Add Makefile support for TEST_GEN_PROGS_EXTENDED
>    vfio: selftests: Expose iommu_modes to tests
>    vfio: selftests: Verify that opening VFIO device fails during Live
>      Update
>    vfio: selftests: Add continuous DMA to vfio_pci_liveupdate_kexec_test
>
> Vipin Sharma (13):
>    vfio/pci: Factor out the reset logic in VFIO PCI device close path
>    vfio: Export various helpers from VFIO
>    vfio/pci: Export vfio_pci_dma_buf_move for vfio-pci module
>    liveupdate: Export symbols needed by modules
>    vfio/pci: Register a file handler with Live Update Orchestrator
>    vfio/pci: Preserve vfio-pci device files across Live Update
>    vfio: Introduce vfio_find_device() helper
>    vfio: Refactor vfio_device_fops_cdev_open()
>    vfio: Add API to open cdev device for Live Update restore
>    vfio/pci: Retrieve preserved device files after Live Update
>    vfio: selftests: Build liveupdate library in VFIO selftests
>    vfio: selftests: Initialize vfio_pci_device using a VFIO cdev FD
>    vfio: selftests: Add vfio_pci_liveupdate_kexec_test
>
>   Documentation/core-api/liveupdate.rst         |   1 +
>   .../driver-api/vfio_pci_liveupdate.rst        |  23 ++
>   MAINTAINERS                                   |   2 +
>   drivers/vfio/device_cdev.c                    |  67 +++-
>   drivers/vfio/group.c                          |   9 +
>   drivers/vfio/pci/Kconfig                      |  12 +
>   drivers/vfio/pci/Makefile                     |   1 +
>   drivers/vfio/pci/vfio_pci.c                   |  13 +-
>   drivers/vfio/pci/vfio_pci_config.c            |   3 +
>   drivers/vfio/pci/vfio_pci_core.c              | 119 +++---
>   drivers/vfio/pci/vfio_pci_dmabuf.c            |   1 +
>   drivers/vfio/pci/vfio_pci_liveupdate.c        | 340 ++++++++++++++++++
>   drivers/vfio/pci/vfio_pci_priv.h              |  28 ++
>   drivers/vfio/vfio.h                           |  18 +
>   drivers/vfio/vfio_main.c                      |  67 +++-
>   include/linux/kho/abi/vfio_pci.h              |  43 +++
>   include/linux/vfio.h                          |  12 +
>   include/linux/vfio_pci_core.h                 |   3 +
>   kernel/liveupdate/luo_file.c                  |   2 +
>   tools/testing/selftests/vfio/Makefile         |  23 +-
>   .../vfio/lib/include/libvfio/iommu.h          |   2 +
>   .../lib/include/libvfio/vfio_pci_device.h     |   3 +
>   tools/testing/selftests/vfio/lib/iommu.c      |   4 +-
>   .../selftests/vfio/lib/vfio_pci_device.c      |  25 +-
>   .../vfio/vfio_pci_liveupdate_kexec_test.c     | 256 +++++++++++++
>   .../vfio/vfio_pci_liveupdate_uapi_test.c      |  97 +++++
>   26 files changed, 1097 insertions(+), 77 deletions(-)
>   create mode 100644 Documentation/driver-api/vfio_pci_liveupdate.rst
>   create mode 100644 drivers/vfio/pci/vfio_pci_liveupdate.c
>   create mode 100644 include/linux/kho/abi/vfio_pci.h
>   create mode 100644 tools/testing/selftests/vfio/vfio_pci_liveupdate_kexec_test.c
>   create mode 100644 tools/testing/selftests/vfio/vfio_pci_liveupdate_uapi_test.c
>
>
> base-commit: cbf37fff757e87376e80e11a8378393a8f25145f
> prerequisite-patch-id: 85705fb54d3065efe1d87ab4b69e828a9f3404e7
> prerequisite-patch-id: a33ae79b5fc0259bd013b430c18cc3d14a678599

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