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

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

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.

Yanjun.Zhu

>
> Let me know if you still face some issue in running Live Update, I will
> be happy to provide more details.
>
> Thanks
> Vipin