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

[Vipin Sharma <vipinsh@google.com>]

On Thu, Jul 23, 2026 at 03:18:55PM -0700, Yanjun.Zhu wrote:
> 
> On 7/20/26 10:08 AM, Vipin Sharma wrote:
> > On Thu, Jul 16, 2026 at 06:22:07PM -0700, Yanjun.Zhu wrote:
> > > On 7/16/26 4:24 PM, Yanjun.Zhu wrote:
> > > > 
> > > > On 7/14/26 8:14 AM, Vipin Sharma wrote:
> > > > > 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?
> > Sorry, this was my copy-paste mistake when combining things from both
> > qemu and baremetal. You only need one device not two separate ones.
> > 
> > For testing using QEMU, you can use QEMU PCI test device.
> > 
> >    -device pci-testdev
> > 
> > In VM, use `lspci` command to find the BDF of the PCI device. It will show
> > output like:
> > 
> >    00:04.0 Unclassified device [00ff]: Red Hat, Inc. QEMU PCI Test Device
> > 
> > Then prefix the domain (generally, 0000) to the BDF and use the testing
> > commands.
> > 
> > `0000:6a:01.0` was the BDF of the Intel DSA device on my host. I
> > incorrectly mixed two devices during my copy-paste.
> > 
> > Limitation of qemu pci-testdev is that it does not have the DMA
> > capability. I used physical host with Intel DSA to verify that the
> > device performing DMA during live update gets reset.
> > 
> > > In my qemu,
> > > 
> > > 00:04.0 System peripheral: InnoTek Systemberatung GmbH VirtualBox Guest
> > > Service
> > >      Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr-
> > > Stepping- SERR- FastB2B- DisINTx-
> > >      Status: Cap- 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort-
> > > <MAbort- >SERR- <PERR- INTx-
> > >      Interrupt: pin A routed to IRQ 20
> > >      Region 0: I/O ports at d040 [size=32]
> > >      Region 1: Memory at f0400000 (32-bit, non-prefetchable) [size=4M]
> > >      Region 2: Memory at f0800000 (32-bit, prefetchable) [size=16K]
> > >      Kernel driver in use: vboxguest
> > >      Kernel modules: vboxguest
> > > 
> > > I am wondering if the above pci device can work well with this patch set or
> > > not.
> > I think you should be able to test Live Update with any PCI device which
> > can be attached vfio-pci driver.
> > 
> > `vfio_pci_liveupdate_kexec_test` will initiate DMA if the VFIO selftest
> > framework has the driver for the passed device (Intel DSA) otherwise it
> > will just skip over the DMA flow and do the remaining things.
> 
> Thanks a lot. I'll run some tests with QEMU's `pci-testdev`.
> 
> If I understand correctly, when using `pci-testdev`, only the DMA test case
> is expected not to work, while all the other test cases should work
> correctly.
> 

Yes, other test cases should work.