Commit 04249f0f94 for qemu.org

commit 04249f0f9447f4bda1d408e0ed8354d71d784830
Author: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Date:   Thu Mar 19 13:59:42 2026 -0700

    hw/vfio/iommufd: report hint to user when vfio-dev/vfio*/dev is missing

    Give a hint about missing kernel config CONFIG_VFIO_DEVICE_CDEV.

    Reviewed-by: Yi Liu <yi.l.liu@intel.com>
    Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
    Reviewed-by: Cédric Le Goater <clg@redhat.com>
    Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
    Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
    Message-ID: <20260319205942.367705-3-pierrick.bouvier@linaro.org>
    Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>

diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
index 131612eb83..3e33dfbb35 100644
--- a/hw/vfio/iommufd.c
+++ b/hw/vfio/iommufd.c
@@ -274,7 +274,10 @@ static int iommufd_cdev_getfd(const char *sysfs_path, Error **errp)
     }

     if (!g_file_get_contents(vfio_dev_path, &contents, &length, NULL)) {
-        error_setg(errp, "failed to load \"%s\"", vfio_dev_path);
+        error_setg(errp,
+                   "failed to load \"%s\""
+                   " (is your kernel config missing CONFIG_VFIO_DEVICE_CDEV?)",
+                   vfio_dev_path);
         goto out_close_dir;
     }