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Re: [Qemu-devel] [PATCH 0/7] s390x/pci: Improve zPCI to cover more cases


From: Christian Borntraeger
Subject: Re: [Qemu-devel] [PATCH 0/7] s390x/pci: Improve zPCI to cover more cases
Date: Tue, 7 Nov 2017 18:50:10 +0100
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0


On 11/07/2017 06:31 PM, Cornelia Huck wrote:
> On Tue,  7 Nov 2017 18:24:32 +0100
> Pierre Morel <address@hidden> wrote:
> 
>> Right now the PCI support is very limited (e.g. pass through of a
>> host vfio device)
>> To enable features like virtio-pci several modifications needs to be
>> done.
>>
>> Virtio-PCI uses subregions, which may eventually be discontinuous
>> inside bars instead of a single flat region.
>> The address offset being formerly calculated from the BAR base address
>> must be adapted to the subregions instead of to the single region.
>>
>> This patch provides the new calculation for the three kind of BAR
>> access, zPCI STORE, zPCI LOAD and zPCI STORE BLOCK.
>>
>> We use the opportunity to
>>  - enhance the fault detection for zPCI STORE and LOAD,
>>  - enhance the fault detection and to provide the maximum STORE BLOCK
>>    block size, maxstbl, for zPCI STORE BLOCK
>>  - factor out part of the code used to calculate the offset and
>>    access the BARs,
>>  - factor out the code for endianess conversion.
> 
> Will look at this later. Just a quick question: What kind of further
> functionality is enabled by this? E.g., I can attach a virtio-net-pci
> device right now, does this enable more virtio devices?

You can attach a virtio-net-pci today, with these patches it now starts to work 
;-)
In essence to me this all looks like a bugfix (a big one though)

> 
>>
>>
>> Pierre Morel (7):
>>   s390x/pci: factor out endianess conversion
>>   s390x/pci: rework PCI STORE
>>   s390x/pci: rework PCI LOAD
>>   s390x/pci: rework PCI STORE BLOCK
>>   s390x/pci: move the memory region read from pcilg
>>   s390x/pci: move the memory region write from pcistg
>>   s390x/pci: search for subregion inside the BARs
>>
>>  hw/s390x/s390-pci-bus.h  |   1 +
>>  hw/s390x/s390-pci-inst.c | 250 
>> ++++++++++++++++++++++++++++-------------------
>>  hw/s390x/s390-pci-inst.h |   2 +-
>>  3 files changed, 153 insertions(+), 100 deletions(-)
>>
> 




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