From: Alex Williamson Date: Thu, 16 May 2024 17:48:30 +0000 (-0600) Subject: vfio/pci: Restore zero affected bus reset devices warning X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=cbb325e77fbe62a06184175aa98c9eb98736c3e8;p=linux.git vfio/pci: Restore zero affected bus reset devices warning 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 Reviewed-by: Cédric Le Goater Reviewed-by: Yi Liu Link: https://lore.kernel.org/r/20240516174831.2257970-1-alex.williamson@redhat.com Signed-off-by: Alex Williamson --- diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c index d8c95cc16be81..80cae87fff36e 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;