Re: [Qemu-devel] [PATCH v1 1/3] sPAPR: Implement PCI error injection RTAS calls

[Gavin Shan <gwshan@linux.vnet.ibm.com>]

On Mon, Jun 23, 2014 at 11:13:45PM +0200, Alexander Graf wrote:
>
>> Am 23.06.2014 um 23:03 schrieb Benjamin Herrenschmidt <benh@kernel.crashing.org>:
>> 
>>> On Mon, 2014-06-23 at 18:18 +0200, Alexander Graf wrote:
>>> Device emulation code shouldn't even remotely have an idea what host 
>>> it's running on. Also semantically there are a few issues with this approach
>>> 
>>>   1) QEMU is usually running with user privileges, so it doesn't have 
>>> access to the file above
>> 
>> Right, this needs to go via VFIO like the rest of the EEH stuff
>> 
>>>   2) QEMU's channel to hardware devices is via normal kernel API. For 
>>> physical devices that's VFIO. No side channels please.
>> 
>> Indeed. If the user gets access to that file, suddenly qemu can
>> "manufacture" a bad string and error inject in other devices it doesn't
>> own which isn't great.
>> 
>> Gavin, this needs to go via the same path as normal EEH and be limited
>> to injecting errors that are completely bounded to the PE.
>> 
>> I don't think this is very high priority. We should first write a good
>> host side error injection tool and sort out the reporting of the EEH log
>> from host to guest.
>> 
>>>   3) Ownership of the question whether a PE is in error mode is 
>>> responsibility of the PHB. In the emulated case, the PHB would have to 
>>> set itself into a mode where it behaves as if it's blocked.
>> 
>> We don't have to support error injection for emulated since we don't
>> support (yet) the rest oF EEH for them. We could one day but it's
>> really not urgent.
>
>I agree, but the layers are the same ;)
>

Thanks, Ben and Alex. Yes, it's fair enough for VFIO (ioctl cmd) to
routing the PCI error injection.

Thanks,
Gavin

>Alex
>
>> 
>> Cheers,
>> Ben.
>>