[libvirt] [PATCH 04/13] qemu: Enable PCI multi bus for S390 guests

[Yi Min Zhao]

在 2018/6/4 下午10:10, Ján Tomko 写道:
> On Mon, Jun 04, 2018 at 01:57:04PM +0800, Yi Min Zhao wrote:
>>
>>
>> 在 2018/6/2 下午10:16, Ján Tomko 写道:
>>> On Thu, May 24, 2018 at 02:24:29PM +0200, Xiao Feng Ren wrote:
>>>> From: Yi Min Zhao <zyimin at linux.ibm.com>
>>>>
>>>> QEMU on s390 supports PCI multibus since forever. But zPCI, as 
>>>> extension
>>>> of PCI device on s390, is the significant capability. Only when zPCI
>>>> capability is existing, we consider QEMU supports PCI multibus 
>>>> properly.
>>>> So let enable PCI multibus only if zPCI is supported.
>>>>
>>>> Signed-off-by: Yi Min Zhao <zyimin at linux.ibm.com>
>>>> Reviewed-by: Boris Fiuczynski <fiuczy at linux.vnet.ibm.com>
>>>> Reviewed-by: Stefan Zimmermann <stzi at linux.ibm.com>
>>>> Reviewed-by: Bjoern Walk <bwalk at linux.vnet.ibm.com>
>>>> ---
>>>> src/qemu/qemu_capabilities.c | 3 +++
>>>> 1 file changed, 3 insertions(+)
>>>>
>>>> diff --git a/src/qemu/qemu_capabilities.c 
>>>> b/src/qemu/qemu_capabilities.c
>>>> index e6fd7ee468..3d4f64ca09 100644
>>>> --- a/src/qemu/qemu_capabilities.c
>>>> +++ b/src/qemu/qemu_capabilities.c
>>>> @@ -1716,6 +1716,9 @@ bool virQEMUCapsHasPCIMultiBus(virQEMUCapsPtr
>>>> qemuCaps,
>>>>         return false;
>>>>     }
>>>>
>>>> +    if (ARCH_IS_S390(def->os.arch))
>>>
>>> This includes S390 as well as S390X, do we care about that distinction?
>> No need, at least from my point of view.
>
> On second thought, if this is the only way to get PCI to work on S390,
> this particular function should not be capability-based but always
> return true - it merely says whether to use pci.0 vs. pci for the 0th
> bus, not whether PCI is actually supported or not.
>
> Jano
Yes, I agree with you. Only pci.0 is supported on s390 throughout.