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

[Alex Williamson]

On Tue, 7 Jul 2020 23:28:39 +0000
"Tian, Kevin" <kevin.tian at 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,

Alex


> > From: Zhenyu Wang <zhenyuw at 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  
>