[Intel-gfx] [PATCH v6 09/24] vfio/pci: Only need to check opened devices in the dev_set for hot reset

[Tian, Kevin]

> From: Liu, Yi L <yi.l.liu at intel.com>
> Sent: Wednesday, March 8, 2023 9:29 PM
>
> @@ -2429,10 +2429,23 @@ static int vfio_pci_dev_set_hot_reset(struct
> vfio_device_set *dev_set,
> 
>  	list_for_each_entry(cur_vma, &dev_set->device_list,
> vdev.dev_set_list) {
>  		/*
> -		 * Test whether all the affected devices are contained by the
> +		 * Test whether all the affected devices can be reset by the
> +		 * user.  The affected devices may already been opened or
> not
> +		 * yet.
> +		 *
> +		 * For the devices not opened yet, user can reset them as it
> +		 * reason is that the hot reset is done under the protection
> +		 * of the dev_set->lock, and device open is also under this
> +		 * lock.  During the hot reset, such devices can not be opened
> +		 * by other users.
> +		 *
> +		 * For the devices that have been opened, needs to check the
> +		 * ownership.  If the user provides a set of group fds, test
> +		 * whether all the opened affected devices are contained by
> the
>  		 * set of groups provided by the user.
>  		 */

		 * Test whether all the affected devices can be reset by the
		 * user.
		 *
		 * Resetting an unused device (not opened) is safe, because
		 * dev_set->lock is held in hot reset path so this device
		 * cannot race being opened by another user simultaneously.
		 *
		 * Otherwise all opened devices in the dev_set must be
		 * contained by the set of groups provided by the user.

the rest looks good:

Reviewed-by: Kevin Tian <kevin.tian at intel.com>