[cc +Halil] On Mon, 26 Nov 2018 16:48:50 +0800 Zhenyu Wang <zhenyuw@xxxxxxxxxxxxxxx> wrote: > Hi, > > This is respin of previous sending from https://www.spinics.net/lists/kvm/msg176447.html > > 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]. > > To allow to create user defined resources for mdev, it trys to extend mdev > create interface by adding new "aggregate=xxx" parameter following UUID, for > target mdev type if aggregation is supported, it can create new mdev device > which contains resources combined by number of instances, e.g > > echo "<uuid>,aggregate=10" > create > > VM manager e.g libvirt can check mdev type with "aggregation" attribute which > can support this setting. If no "aggregation" attribute found for mdev type, > previous behavior is still kept for one instance allocation. And new sysfs > attribute "aggregated_instances" is created for each mdev device to show allocated number. Halil, I hope I'm not mis-remembering, but I think you mentioned some apprehension of this aggregation attribute with regard to the spirit of mdev devices at KVM Forum. If that's correct, do you have any comments on this series or suggestions towards a better interface? Obviously this is an optional attribute targeting devices which can scale with a semi-arbitrary number of instances behind a single device, where specifying an mdev type for each enumeration of those aggregate instances in impractical. I don't know that there's anything similar in AP, but if we're missing some alignment between interfaces, please speak up. Thanks, Alex > 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 > > v2: > - Add new create_with_instances driver hook > - Update doc for new attributes > > v3: > - Rename parameter and attribute names from review > - Make "aggregation" attribute to show maxium resource number > for aggregation > - Check driver hooks for attribute create validation > - Update doc and ABI spec > > v4: > - Rebase > > Zhenyu Wang (6): > vfio/mdev: Add new "aggregate" parameter for mdev create > vfio/mdev: Add "aggregation" attribute for supported mdev type > vfio/mdev: Add "aggregated_instances" attribute for supported mdev > device > Documentation/vfio-mediated-device.txt: Update for vfio/mdev > aggregation support > Documentation/ABI/testing/sysfs-bus-vfio-mdev: Update for vfio/mdev > aggregation support > drm/i915/gvt: Add new type with aggregation support > > Documentation/ABI/testing/sysfs-bus-vfio-mdev | 25 +++++++ > Documentation/vfio-mediated-device.txt | 44 +++++++++-- > drivers/gpu/drm/i915/gvt/gvt.h | 11 ++- > drivers/gpu/drm/i915/gvt/kvmgt.c | 53 ++++++++++++- > drivers/gpu/drm/i915/gvt/vgpu.c | 56 +++++++++++++- > drivers/vfio/mdev/mdev_core.c | 40 +++++++++- > drivers/vfio/mdev/mdev_private.h | 6 +- > drivers/vfio/mdev/mdev_sysfs.c | 74 ++++++++++++++++++- > include/linux/mdev.h | 19 +++++ > 9 files changed, 305 insertions(+), 23 deletions(-) >
