On Wed, 12 Apr 2023 12:05:50 -0300 Jason Gunthorpe <jgg@xxxxxxxxxx> wrote: > On Wed, Apr 12, 2023 at 07:27:43AM +0000, Tian, Kevin wrote: > > > From: Jason Gunthorpe > > > Sent: Wednesday, April 12, 2023 8:01 AM > > > > > > I see this problem as a few basic requirements from a qemu-like > > > application: > > > > > > 1) Does the configuration I was given support reset right now? > > > 2) Will the configuration I was given support reset for the duration > > > of my execution? > > > 3) What groups of the devices I already have open does the reset > > > effect? > > > 4) For debugging, report to the user the full list of devices in the > > > reset group, in a way that relates back to sysfs. > > > 5) Away to trigger a reset on a group of devices > > > > > > #1/#2 is the API I suggested here. Ask the kernel if the current > > > configuration works, and ask it to keep it working. > > > > > > #3 is either INFO and a CAP for BDF or INFO2 reporting dev_id > > > > > > #4 is either INFO and print the BDFs or INFO2 reporting the struct > > > vfio_device IDR # (eg /sys/class/vfio/vfioXXX/). > > > > mdev doesn't have BDF. Of course it doesn't support hot_reset either. > > It should support a reset.. Maybe idxd doesn't, but it should be part > of the SIOV model. Our SIOV devices would need it for instance. IIRC we require mdev devices to support VFIO_DEVICE_RESET, hot-reset is a different beast. I assume SIOV device support would also require VFIO_DEVICE_RESET support and hot-reset would also be irrelevant to them. > > but it's presented to userspace as a pci device. Is it weird for a pci > > device which doesn't provide a BDF cap? > > It is weird for a PCI device, but it is not weird for a VFIO > device. Leaking the physical labels out of the uAPI is not clean, > IMHO. > > > from this point the vfio_device IDR# sounds more generic. > > Yes, I was thinking about this for the SIOV model. Seems like we're off on a tangent, the hot-reset ioctl is not relevant to devices simply because they expose a vfio-pci API, there is any underlying hardware aspect that anything that is only virtualizing a vfio-pci API shouldn't be concerned with. Thanks, Alex
