[PATCH v2 13/40] vfio: Add support for Shared Virtual Addressing

Xu Zaibo xuzaibo at huawei.com
Mon Sep 3 19:12:37 PDT 2018



On 2018/9/3 18:34, Jean-Philippe Brucker wrote:
> On 01/09/18 03:23, Xu Zaibo wrote:
>> As one application takes a whole function while using VFIO-PCI, why do
>> the application and the
>> function need to enable PASID capability? (Since just one I/O page table
>> is enough for them.)
> At the moment the series doesn't provide support for SVA without PASID
> (on the I/O page fault path, 08/40). In addition the BIND ioctl could be
> used by the owner application to bind other processes (slaves) and
> perform sub-assignment. But that feature is incomplete because we don't
> send stop_pasid notification to the owner when a slave dies.
>
So, Could I understand like this?

     1. While the series are finished well, VFIO-PCI device can be held 
by only one process
         through binding IOCTL command without PASID (without PASID 
being exposed user space).

     2. While using VFIO-PCI device to support multiple processes with 
SVA series, a primary
         process with multiple secondary processes must be deployed just 
like DPDK(https://www.dpdk.org/).
         And, the PASID still has to be exposed to user land.


Thanks,
Zaibo

.





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