commit b1f521de8b2f356f4ae7683c51aa8c3ba6c7931e
author John Levon <john.levon@nutanix.com> Mon Jun 16 03:13:36 2025 -0700
committer Cédric Le Goater <clg@redhat.com> Thu Jun 26 08:55:37 2025 +0200
tree 75a5b6012deb6f93f4b66aa68faa5a33e9d7647f
parent 639ff87a1a823715f16edec34caacd8ef824fcfd

vfio: add vfio_device_get_region_fd()

This keeps the existence of ->region_fds private to hw/vfio/device.c.

Signed-off-by: John Levon <john.levon@nutanix.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Link: https://lore.kernel.org/qemu-devel/20250616101337.3190027-1-john.levon@nutanix.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>

hw/vfio/device.c

diff --git a/hw/vfio/device.c b/hw/vfio/device.c
index d32600e..d91c695 100644
--- a/hw/vfio/device.c
+++ b/hw/vfio/device.c
@@ -243,6 +243,13 @@
     return 0;
 }
 
+int vfio_device_get_region_fd(VFIODevice *vbasedev, int index)
+{
+        return vbasedev->region_fds ?
+               vbasedev->region_fds[index] :
+               vbasedev->fd;
+}
+
 int vfio_device_get_region_info_type(VFIODevice *vbasedev, uint32_t type,
                                      uint32_t subtype, struct vfio_region_info **info)
 {

hw/vfio/region.c

diff --git a/hw/vfio/region.c b/hw/vfio/region.c
index f5b8e3c..d04c57d 100644
--- a/hw/vfio/region.c
+++ b/hw/vfio/region.c
@@ -273,10 +273,7 @@
             goto no_mmap;
         }
 
-        /* Use the per-region fd if set, or the shared fd. */
-        fd = region->vbasedev->region_fds ?
-             region->vbasedev->region_fds[region->nr] :
-             region->vbasedev->fd,
+        fd = vfio_device_get_region_fd(region->vbasedev, region->nr);
 
         map_align = (void *)ROUND_UP((uintptr_t)map_base, (uintptr_t)align);
         munmap(map_base, map_align - map_base);

include/hw/vfio/vfio-device.h

diff --git a/include/hw/vfio/vfio-device.h b/include/hw/vfio/vfio-device.h
index d45e5a6..1926adb 100644
--- a/include/hw/vfio/vfio-device.h
+++ b/include/hw/vfio/vfio-device.h
@@ -256,6 +256,18 @@
                                 struct vfio_region_info **info);
 int vfio_device_get_region_info_type(VFIODevice *vbasedev, uint32_t type,
                                      uint32_t subtype, struct vfio_region_info **info);
+
+/**
+ * Return the fd for mapping this region. This is either the device's fd (for
+ * e.g. kernel vfio), or a per-region fd (for vfio-user).
+ *
+ * @vbasedev: #VFIODevice to use
+ * @index: region index
+ *
+ * Returns the fd.
+ */
+int vfio_device_get_region_fd(VFIODevice *vbasedev, int index);
+
 bool vfio_device_has_region_cap(VFIODevice *vbasedev, int region, uint16_t cap_type);
 
 int vfio_device_get_irq_info(VFIODevice *vbasedev, int index,