On Tue, Aug 04, 2026 at 03:19:34PM -0700, Yanjun.Zhu wrote: > > On 7/14/26 8:15 AM, Vipin Sharma wrote: > > Add a selftest to exercise preserving a vfio-pci device across a Live > > Update. For now the test is extremely simple and just verifies that the > > device file can be preserved and retrieved. In the future this test will > > be extended to verify more parts about device preservation as they are > > implemented. > > > > This test is added to TEST_GEN_PROGS_EXTENDED since it must be run > > manually along with a kexec. > > > > To run this test manually: > > > > $ tools/testing/selftests/vfio/scripts/setup.sh 0000:00:04.0 > > $ tools/testing/selftests/vfio/vfio_pci_liveupdate_kexec_test --stage 1 > > 0000:00:04.0 > > > > $ kexec ... # NOTE: Exact method will be distro-dependent > > > > $ tools/testing/selftests/vfio/scripts/setup.sh 0000:00:04.0 > > $ tools/testing/selftests/vfio/vfio_pci_liveupdate_kexec_test --stage 2 > > 0000:00:04.0 > Hi, Vipin > > Thanks a lot for your help. I followed your suggestion, vfio-pci setup can > work.
I am glad your setup using virsh is working. > > The followings are the test result. In the step 3, after kexec, there are > some fails. I am not sure if these are known problem or not. > > 1. Before kexec command > > + modprobe -v vfio-pci > + tools/testing/selftests/vfio/scripts/setup.sh 0000:00:04.0 > + echo "vfio-pci" > /sys/bus/pci/devices/0000:00:04.0/driver_override > + echo "0000:00:04.0" > /sys/bus/pci/drivers/vfio-pci/bind > + tools/testing/selftests/vfio/vfio_pci_liveupdate_kexec_test --stage 1 > 0000:00:04.0 > Preserving device in session > Preserving memfd of size 0x40100000 in session > # [STAGE 1] Forking persistent child to hold sessions... > # [STAGE 1] Child PID: 1236. Resources are pinned. > # [STAGE 1] You may now perform kexec reboot. > + set +x > > 2. Run kexec command > > 3. After kexec command > > + echo "vfio-pci" > /sys/bus/pci/devices/0000:00:04.0/driver_override > + echo "0000:00:04.0" > /sys/bus/pci/drivers/vfio-pci/bind > Checking open(/dev/vfio/devices/vfio0) fails <--- I can confirm that the > /dev/vfio/devices/vfio0 exists. But open this failed. This is correct output. Test is verifying that open should fail. If it didn't fail the ntest would have exited with an error. A preserved VFIO FD can only be retrived using Live Update session ioctls and not through usual VFIO dev path. > Checking ioctl(group_fd, VFIO_GROUP_GET_DEVICE_FD, "0000:00:04.0") fails > (vfio_type1_iommu) <--- fails > Checking ioctl(group_fd, VFIO_GROUP_GET_DEVICE_FD, "0000:00:04.0") fails > (vfio_type1v2_iommu). <--- fails > Checking ioctl(group_fd, VFIO_GROUP_GET_DEVICE_FD, "0000:00:04.0") fails > (iommufd_compat_type1) <--- fails > Checking ioctl(group_fd, VFIO_GROUP_GET_DEVICE_FD, "0000:00:04.0") fails > (iommufd_compat_type1v2). <--- fails These are all correct output. Test is verifying that userspace should not be able to get VFIO device FD only through Live Update session ioctls and nothing else. > Retrieving memfd from LUO > Finishing the session before retrieving the device (should fail) > Retrieving the device FD from LUO > Finishing the session before binding to iommufd (should fail) > Binding the device to an iommufd and setting it up > Finishing the session > This is shows VFIO FD is successfully retrived by Live Update ioctl. So, you saw expected output from successful test run. I will change the message getting printed to avoid confusion. I think current way of printing ".... fails" is confusing. Thanks Vipin
