Subject: Re: [PATCH v7 3/3] drivers/vfio: EEH support for VFIO PCI device

From: Alexey Kardashevskiy <[email-masked]>
Date: Fri, 30 May 2014 13:44:04 +1000

On 05/29/2014 07:58 AM, Benjamin Herrenschmidt wrote:
> On Wed, 2014-05-28 at 22:49 +1000, Gavin Shan wrote:
>>
>> I will remove those "address" related macros in next revision because it's
>> user-level bussiness, not related to host kernel any more.
>>
>> If the user is QEMU + guest, we need the address to identify the PE though PHB
>> BUID could be used as same purpose to get PHB, which is one-to-one mapping with
>> IOMMU group on sPAPR platform. However, once the PE address is built and returned
>> to guest, guest will use the PE address as input parameter in subsequent RTAS
>> calls.
>>
>> If the user is some kind of application who just uses the ioctl() without supporting
>> RTAS calls. We don't need care about PE address. 
> 
> I am a bit reluctant with that PE==PHB equation we seem to be introducing.
>
> This isn't the case in HW.

It is pseries, not real HW. Does phyp allow multiple real host PEs on the
same virtual PHB?

> It's possible that this is how we handle VFIO *today*
> in qemu but it doesn't have to be does it ?
> 
> It also paints us into a corner if we want to start implementing some kind of
> emulated EEH for selected emulated devices and/or virtio.

-- 
Alexey