Re: [Qemu-devel] [PATCH] spapr-pci: remove io ports workaround

[Alexander Graf]

On 11.12.2013, at 07:47, Alexey Kardashevskiy <address@hidden> wrote:

> On 12/10/2013 06:47 PM, Greg Kurz wrote:
>> On Tue, 10 Dec 2013 13:43:05 +1100
>> Alexey Kardashevskiy <address@hidden> wrote:
>>> On 12/10/2013 03:33 AM, Greg Kurz wrote:
>>>> In the past, IO space could not be mapped into the memory address space
>>>> so we introduced a workaround for that. Nowadays it does not look
>>>> necessary so we can remove the workaround and make sPAPR PCI
>>>> configuration simplier.
>>>> 
>>>> This workaround has also an evil side effect with virtio devices:
>>>> because all PHBs have their .io region at the same address, the devices
>>>> get mapped in the .io-alias region of every PHB (AKA. mapped multiple
>>>> times). This breaks the ioeventfd feature and causes qemu to abort()
>>>> when running with KVM and asking for more than one PHB:
>>>> 
>>>> $ qemu-system-ppc64 -machine type=pseries,accel=kvm -smp 1 -m 4G \
>>>>  -hda /local/greg/images/fedora-be.qcow2 \
>>>>  -device
>>>> virtio-9p-pci,fsdev=fsdev0,mount_tag=share,bus=pci,ioeventfd=on \
>>>> -fsdev local,security_model=none,id=fsdev0,path=$HOME/share1 \ -device
>>>> spapr-pci-host-bridge,index=15 kvm_mem_ioeventfd_add: error adding
>>>> ioeventfd: File exists Aborted
>>>> 
>>>> This will prevent to use virtio and VFIO passthrough at the same time,
>>>> since VFIO needs a dedicated PHB to work on ppc.
>>>> 
>>>> Signed-off-by: Alexey Kardashevskiy <address@hidden>
>>> 
>>> 
>>> I have not seen this version yet so please remove me from "SOB". The patch
>>> you replied to was eventually reworked and went to upstream as
>>> 66aab867cedd2a2d81b4d64eff7c3e0f6f272bbf
>>> 
>> 
>> Hi Alex,
>> 
>> I agree you have not seen this version yet... The patch I replied to was my
>> primary source of inspiration and contains these bits, hence the SOB. 
>> Anyway, the SOB is now removed until you decide to add one yourself. :)
>> 
>>> This one might be correct too but I want to try this first :)
>>> 
>> 
>> Well, I hope it is. Please try it.
> 
> 
> Yep. Tried. Looks good, did not break a thing as far as I can tell, even
> VGA works :)
> 
> 
> Signed-off-by: Alexey Kardashevskiy <address@hidden>

Thanks, applied to ppc-next.


Alex