> From: Alex Williamson <alex.williamson@xxxxxxxxxx>
> Sent: Friday, May 17, 2024 1:49 AM
>
> Yi notes relative to commit f6944d4a0b87 ("vfio/pci: Collect hot-reset
> devices to local buffer") that we previously tested the resulting
> device count with a WARN_ON, which was removed when we switched to
> the in-loop user copy in commit b56b7aabcf3c ("vfio/pci: Copy hot-reset
> device info to userspace in the devices loop"). Finding no devices in
> the bus/slot would be an unexpected condition, so let's restore the
> warning and trigger a -ERANGE error here as success with no devices
> would be an unexpected result to userspace as well.
>
> Suggested-by: Yi Liu <yi.l.liu@xxxxxxxxx>
> Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
> ---
> drivers/vfio/pci/vfio_pci_core.c | 3 +++
> 1 file changed, 3 insertions(+)
Reviewed-by: Yi Liu <yi.l.liu@xxxxxxxxx>
> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
> index d8c95cc16be8..80cae87fff36 100644
> --- a/drivers/vfio/pci/vfio_pci_core.c
> +++ b/drivers/vfio/pci/vfio_pci_core.c
> @@ -1281,6 +1281,9 @@ static int vfio_pci_ioctl_get_pci_hot_reset_info(
> if (ret)
> return ret;
>
> + if (WARN_ON(!count)) /* Should always be at least one */
> + return -ERANGE;
> +
> if (count > (hdr.argsz - sizeof(hdr)) / sizeof(*devices)) {
> hdr.count = count;
> ret = -ENOSPC;
> --
> 2.44.0
Regards,
Yi Liu
