Re: [PATCH v3 0/2] VFIO mdev aggregated resources handling

[Zhenyu Wang <zhenyuw@linux.intel.com>]

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On 2020.07.07 19:06:34 -0600, Alex Williamson wrote:
> On Tue, 7 Jul 2020 23:28:39 +0000
> "Tian, Kevin" <kevin.tian@intel.com> wrote:
> 
> > Hi, Alex, 
> > 
> > Gentle ping... Please let us know whether this version looks good.
> 
> I figured this is entangled with the versioning scheme.  There are
> unanswered questions about how something that assumes a device of a
> given type is software compatible to another device of the same type
> handles aggregation and how the type class would indicate compatibility
> with an aggregated instance.  Thanks,
> 

+Yan

Alex, If no concern on aggregated resources info for instance that would
be vendor's behavior to determine what type of resources would be aggregated,
then I'll check with Yan to see how to fulfill this during migration.

Thanks

> 
> 
> > > From: Zhenyu Wang <zhenyuw@linux.intel.com>
> > > Sent: Wednesday, April 8, 2020 1:58 PM
> > > 
> > > Hi,
> > > 
> > > This is a refresh on previous series:
> > > https://patchwork.kernel.org/cover/11208279/
> > > and https://patchwork.freedesktop.org/series/70425/
> > > 
> > > Current mdev device create interface depends on fixed mdev type, which
> > > get uuid from user to create instance of mdev device. If user wants to
> > > use customized number of resource for mdev device, then only can
> > > create new mdev type for that which may not be flexible. This
> > > requirement comes not only from to be able to allocate flexible
> > > resources for KVMGT, but also from Intel scalable IO virtualization
> > > which would use vfio/mdev to be able to allocate arbitrary resources
> > > on mdev instance. More info on [1] [2] [3].
> > > 
> > > As we agreed that for current opaque mdev device type, we'd still
> > > explore management interface based on mdev sysfs definition. And this
> > > one tries to follow Alex's previous suggestion to create generic
> > > parameters under 'mdev' directory for each device, so vendor driver
> > > could provide support like as other defined mdev sysfs entries.
> > > 
> > > For mdev type with aggregation support, files as "aggregated_instances"
> > > and "max_aggregation" should be created under 'mdev' directory. E.g
> > > 
> > > /sys/devices/pci0000:00/0000:00:02.0/<UUID>/mdev/
> > >    |-- aggregated_instances
> > >    |-- max_aggregation
> > > 
> > > "aggregated_instances" is used to set or return current number of
> > > instances for aggregation, which can not be larger than "max_aggregation".
> > > 
> > > The first patch is to update the document for new mdev parameter directory.
> > > The second one is to add aggregation support in GVT driver.
> > > 
> > > References:
> > > [1] https://software.intel.com/en-us/download/intel-virtualization-
> > > technology-for-directed-io-architecture-specification
> > > [2] https://software.intel.com/en-us/download/intel-scalable-io-
> > > virtualization-technical-specification
> > > [3] https://schd.ws/hosted_files/lc32018/00/LC3-SIOV-final.pdf
> > > 
> > > Changelog:
> > > v3:
> > > - add more description for sysfs entries
> > > - rebase GVT support
> > > - rename accounting function
> > > 
> > > Zhenyu Wang (2):
> > >   Documentation/driver-api/vfio-mediated-device.rst: update for
> > >     aggregation support
> > >   drm/i915/gvt: mdev aggregation type
> > > 
> > >  .../driver-api/vfio-mediated-device.rst       |  22 +++
> > >  drivers/gpu/drm/i915/gvt/aperture_gm.c        |  44 +++--
> > >  drivers/gpu/drm/i915/gvt/gtt.c                |   9 +-
> > >  drivers/gpu/drm/i915/gvt/gvt.c                |   7 +-
> > >  drivers/gpu/drm/i915/gvt/gvt.h                |  42 +++--
> > >  drivers/gpu/drm/i915/gvt/kvmgt.c              | 115 +++++++++++-
> > >  drivers/gpu/drm/i915/gvt/vgpu.c               | 172 ++++++++++++------
> > >  7 files changed, 317 insertions(+), 94 deletions(-)
> > > 
> > > --
> > > 2.25.1  
> > 
> 

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