Re: [PATCH 1/2] vfio: rename field to "num_initial_regions"

["Cédric Le Goater" <clg@redhat.com>]

On 10/14/25 17:12, John Levon wrote:
> We set VFIODevice::num_regions at initialization time, and do not
> otherwise refresh it. As it is valid in theory for a VFIO device to
> later increase the number of supported regions, rename the field to
> "num_initial_regions" to better reflect its semantics.
> 
> Signed-off-by: John Levon <john.levon@nutanix.com>


Reviewed-by: Cédric Le Goater <clg@redhat.com>

Thanks,

C.


> ---
>   include/hw/vfio/vfio-device.h |  2 +-
>   hw/vfio-user/device.c         |  2 +-
>   hw/vfio/ccw.c                 |  4 ++--
>   hw/vfio/device.c              | 12 ++++++------
>   hw/vfio/iommufd.c             |  3 ++-
>   hw/vfio/pci.c                 |  4 ++--
>   6 files changed, 14 insertions(+), 13 deletions(-)
> 
> diff --git a/include/hw/vfio/vfio-device.h b/include/hw/vfio/vfio-device.h
> index 7e9aed6d3c..0fe6c60ba2 100644
> --- a/include/hw/vfio/vfio-device.h
> +++ b/include/hw/vfio/vfio-device.h
> @@ -74,7 +74,7 @@ typedef struct VFIODevice {
>       VFIODeviceOps *ops;
>       VFIODeviceIOOps *io_ops;
>       unsigned int num_irqs;
> -    unsigned int num_regions;
> +    unsigned int num_initial_regions;
>       unsigned int flags;
>       VFIOMigration *migration;
>       Error *migration_blocker;
> diff --git a/hw/vfio-user/device.c b/hw/vfio-user/device.c
> index 0609a7dc25..64ef35b320 100644
> --- a/hw/vfio-user/device.c
> +++ b/hw/vfio-user/device.c
> @@ -134,7 +134,7 @@ static int vfio_user_device_io_get_region_info(VFIODevice *vbasedev,
>       VFIOUserFDs fds = { 0, 1, fd};
>       int ret;
>   
> -    if (info->index > vbasedev->num_regions) {
> +    if (info->index > vbasedev->num_initial_regions) {
>           return -EINVAL;
>       }
>   
> diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c
> index 9560b8d851..4d9588e7aa 100644
> --- a/hw/vfio/ccw.c
> +++ b/hw/vfio/ccw.c
> @@ -484,9 +484,9 @@ static bool vfio_ccw_get_region(VFIOCCWDevice *vcdev, Error **errp)
>        * We always expect at least the I/O region to be present. We also
>        * may have a variable number of regions governed by capabilities.
>        */
> -    if (vdev->num_regions < VFIO_CCW_CONFIG_REGION_INDEX + 1) {
> +    if (vdev->num_initial_regions < VFIO_CCW_CONFIG_REGION_INDEX + 1) {
>           error_setg(errp, "vfio: too few regions (%u), expected at least %u",
> -                   vdev->num_regions, VFIO_CCW_CONFIG_REGION_INDEX + 1);
> +                   vdev->num_initial_regions, VFIO_CCW_CONFIG_REGION_INDEX + 1);
>           return false;
>       }
>   
> diff --git a/hw/vfio/device.c b/hw/vfio/device.c
> index 64f8750389..52079f4cf5 100644
> --- a/hw/vfio/device.c
> +++ b/hw/vfio/device.c
> @@ -257,7 +257,7 @@ int vfio_device_get_region_info_type(VFIODevice *vbasedev, uint32_t type,
>   {
>       int i;
>   
> -    for (i = 0; i < vbasedev->num_regions; i++) {
> +    for (i = 0; i < vbasedev->num_initial_regions; i++) {
>           struct vfio_info_cap_header *hdr;
>           struct vfio_region_info_cap_type *cap_type;
>   
> @@ -466,7 +466,7 @@ void vfio_device_prepare(VFIODevice *vbasedev, VFIOContainer *bcontainer,
>       int i;
>   
>       vbasedev->num_irqs = info->num_irqs;
> -    vbasedev->num_regions = info->num_regions;
> +    vbasedev->num_initial_regions = info->num_regions;
>       vbasedev->flags = info->flags;
>       vbasedev->reset_works = !!(info->flags & VFIO_DEVICE_FLAGS_RESET);
>   
> @@ -476,10 +476,10 @@ void vfio_device_prepare(VFIODevice *vbasedev, VFIOContainer *bcontainer,
>       QLIST_INSERT_HEAD(&vfio_device_list, vbasedev, global_next);
>   
>       vbasedev->reginfo = g_new0(struct vfio_region_info *,
> -                               vbasedev->num_regions);
> +                               vbasedev->num_initial_regions);
>       if (vbasedev->use_region_fds) {
> -        vbasedev->region_fds = g_new0(int, vbasedev->num_regions);
> -        for (i = 0; i < vbasedev->num_regions; i++) {
> +        vbasedev->region_fds = g_new0(int, vbasedev->num_initial_regions);
> +        for (i = 0; i < vbasedev->num_initial_regions; i++) {
>               vbasedev->region_fds[i] = -1;
>           }
>       }
> @@ -489,7 +489,7 @@ void vfio_device_unprepare(VFIODevice *vbasedev)
>   {
>       int i;
>   
> -    for (i = 0; i < vbasedev->num_regions; i++) {
> +    for (i = 0; i < vbasedev->num_initial_regions; i++) {
>           g_free(vbasedev->reginfo[i]);
>           if (vbasedev->region_fds != NULL && vbasedev->region_fds[i] != -1) {
>               close(vbasedev->region_fds[i]);
> diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
> index 68470d552e..10fc065d20 100644
> --- a/hw/vfio/iommufd.c
> +++ b/hw/vfio/iommufd.c
> @@ -663,7 +663,8 @@ found_container:
>       vfio_iommufd_cpr_register_device(vbasedev);
>   
>       trace_iommufd_cdev_device_info(vbasedev->name, devfd, vbasedev->num_irqs,
> -                                   vbasedev->num_regions, vbasedev->flags);
> +                                   vbasedev->num_initial_regions,
> +                                   vbasedev->flags);
>       return true;
>   
>   err_listener_register:
> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> index 06b06afc2b..8b8bc5a421 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -2975,9 +2975,9 @@ bool vfio_pci_populate_device(VFIOPCIDevice *vdev, Error **errp)
>           return false;
>       }
>   
> -    if (vbasedev->num_regions < VFIO_PCI_CONFIG_REGION_INDEX + 1) {
> +    if (vbasedev->num_initial_regions < VFIO_PCI_CONFIG_REGION_INDEX + 1) {
>           error_setg(errp, "unexpected number of io regions %u",
> -                   vbasedev->num_regions);
> +                   vbasedev->num_initial_regions);
>           return false;
>       }
>