vfio: warn if host device rom can't be read

If the device rom can't be read, report an error to the
user. This alerts the user that the device has a bad
state that is causing rom read failure or option rom
loading has been disabled from the device boot menu
(among other reasons).

Signed-off-by: Bandan Das <bsd@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c
index ec9f41b98d..ef615fc28f 100644
--- a/hw/misc/vfio.c
+++ b/hw/misc/vfio.c
@@ -1125,6 +1125,13 @@ static void vfio_pci_load_rom(VFIODevice *vdev)
     vdev->rom_offset = reg_info.offset;
 
     if (!vdev->rom_size) {
+        error_report("vfio-pci: Cannot read device rom at "
+                    "%04x:%02x:%02x.%x\n",
+                    vdev->host.domain, vdev->host.bus, vdev->host.slot,
+                    vdev->host.function);
+        error_printf("Device option ROM contents are probably invalid "
+                    "(check dmesg).\nSkip option ROM probe with rombar=0, "
+                    "or load from file with romfile=\n");
         return;
     }