Re: [PATCH v9 0/7] Power11 support for QEMU [PowerNV]

["Cédric Le Goater" <clg@redhat.com>]

On 8/10/25 08:56, Aditya Gupta wrote:
> Hi Cedric,
> Sorry for the late reply, I am on vacation this week, will try to look
> at this, but reply might be late.
> 
> On 25/08/08 02:32PM, Cédric Le Goater wrote:
>> On 8/8/25 13:59, Aditya Gupta wrote:
>>> Overview
>>> ============
>>>
>>> Add support for Power11 powernv machine type.
>>>
>>>> <...snip...>
>>
>> Booting a PowerNV11 machine crashes QEMU. See below.
>>
>> Are you testing with petitboot kexecing a distro kernel from disk ?
>> Please do and also start a KVM guest. Please check your tests.
> 
> No, I ran the qemu functional tests, and few boot tests with different
> options.
> 
> The functional test already attaches a e1000e device, somehow that
> didn't trigger the same error that you saw (maybe the kernel used
> doesn't have support for that device).
> Will add a test to try petitboot kexec scenario also, so we don't hit
> these kind of issues in future.

I run a multi socket config :

   qemu-system-ppc64 -m 4G -machine powernv11 -smp 16,sockets=2,cores=2,threads=4 -accel tcg,thread=multi
     -kernel ./zImage.epapr
     -initrd ./rootfs.cpio.xz
     -device pcie-pci-bridge,id=bridge1,bus=pcie.1,addr=0x0 -device nvme,bus=pcie.0,addr=0x0,drive=drive0,serial=1234
     -drive file=./Fedora-Cloud-Base-Generic-42-1.1.ppc64le.qcow2,if=none,id=drive0,format=qcow2,cache=none
     -device e1000e,netdev=net0,mac=C0:FF:EE:00:01:05,bus=bridge1,addr=0x3
     -netdev bridge,helper=/usr/libexec/qemu-bridge-helper,br=virbr0,id=net0
     -device nec-usb-xhci,bus=bridge1,addr=0x2
     -device usb-storage,drive=usbkey
     -drive file=usb.img,if=none,id=usbkey,format=raw,cache=none
     -serial mon:stdio -nographic
   
See :

     https://lore.kernel.org/qemu-devel/3b1fcc0a-6ce7-4639-a17c-34d640745c20@redhat.com/

> 
> Regarding KVM guest, iirc we can't start KVM guest for PowerNV yet right
> ?

The QEMU PowerNV machines support emulated KVM guests. XIVE
is a key component in its support, as it controls the wake-up
of the virtual processors.

The QEMU pseries machines support nested too, both implementations:
the initial on OPAL systems and the most recent v2 one for pHyp.

I believe QEMU PowerNV machines support nested KVM too. Never
tried that though.

C.