Re: [PATCH v3 12/12] vfio/pci: Report dev_id in VFIO_DEVICE_GET_PCI_HOT_RESET_INFO

Jason Gunthorpe
2023-04-05T16:37:14Z

On Wed, Apr 05, 2023 at 10:25:45AM -0600, Alex Williamson wrote:

> But that kind of brings to light the question of what does the user do
> when they encounter this situation.

What does it do now when it encounters a group_id it doesn't
understand? Userspace already doesn't know if the foreign group is
open or not, right?

> reset can complete. If the device is opened by a different user, the
> reset is blocked. The only logical conclusion is that the user should
> try the reset regardless of the result of the info ioctl, which the

IMHO my suggested version is still the overall saner uAPI.

An info that basically returns success/fail if reset is security
authorized and information about the reset groupings.

Actual reset follows the returned groupings automatically.

Easy for qemu. Call the info at startup to confirm reset can be
emulated, use the returned information to propogate the reset groups
to the guest. Trigger the reset with no fuss when the guest asks for
it.

Less weird corner cases.

Jason