Re: [PATCH 04/22] hw/vfio/container.c: use QOM casts where appropriate

["Cédric Le Goater" <clg@redhat.com>]

On 7/15/25 11:25, Mark Cave-Ayland wrote:
> Use QOM casts to convert between VFIOContainer and VFIOContainerBase instead
> of accessing bcontainer directly.
> 
> Signed-off-by: Mark Cave-Ayland <mark.caveayland@nutanix.com>


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

Thanks,

C.


> ---
>   hw/vfio/container.c | 31 +++++++++++++------------------
>   1 file changed, 13 insertions(+), 18 deletions(-)
> 
> diff --git a/hw/vfio/container.c b/hw/vfio/container.c
> index 3e13feaa74..f4337741b3 100644
> --- a/hw/vfio/container.c
> +++ b/hw/vfio/container.c
> @@ -71,7 +71,7 @@ static int vfio_dma_unmap_bitmap(const VFIOContainer *container,
>                                    hwaddr iova, ram_addr_t size,
>                                    IOMMUTLBEntry *iotlb)
>   {
> -    const VFIOContainerBase *bcontainer = &container->bcontainer;
> +    const VFIOContainerBase *bcontainer = VFIO_IOMMU(container);
>       struct vfio_iommu_type1_dma_unmap *unmap;
>       struct vfio_bitmap *bitmap;
>       VFIOBitmap vbmap;
> @@ -124,8 +124,7 @@ static int vfio_legacy_dma_unmap_one(const VFIOContainerBase *bcontainer,
>                                        hwaddr iova, ram_addr_t size,
>                                        IOMMUTLBEntry *iotlb)
>   {
> -    const VFIOContainer *container = container_of(bcontainer, VFIOContainer,
> -                                                  bcontainer);
> +    const VFIOContainer *container = VFIO_IOMMU_LEGACY(bcontainer);
>       struct vfio_iommu_type1_dma_unmap unmap = {
>           .argsz = sizeof(unmap),
>           .flags = 0,
> @@ -213,8 +212,7 @@ static int vfio_legacy_dma_map(const VFIOContainerBase *bcontainer, hwaddr iova,
>                                  ram_addr_t size, void *vaddr, bool readonly,
>                                  MemoryRegion *mr)
>   {
> -    const VFIOContainer *container = container_of(bcontainer, VFIOContainer,
> -                                                  bcontainer);
> +    const VFIOContainer *container = VFIO_IOMMU_LEGACY(bcontainer);
>       struct vfio_iommu_type1_dma_map map = {
>           .argsz = sizeof(map),
>           .flags = VFIO_DMA_MAP_FLAG_READ,
> @@ -246,8 +244,7 @@ static int
>   vfio_legacy_set_dirty_page_tracking(const VFIOContainerBase *bcontainer,
>                                       bool start, Error **errp)
>   {
> -    const VFIOContainer *container = container_of(bcontainer, VFIOContainer,
> -                                                  bcontainer);
> +    const VFIOContainer *container = VFIO_IOMMU_LEGACY(bcontainer);
>       int ret;
>       struct vfio_iommu_type1_dirty_bitmap dirty = {
>           .argsz = sizeof(dirty),
> @@ -272,8 +269,7 @@ vfio_legacy_set_dirty_page_tracking(const VFIOContainerBase *bcontainer,
>   static int vfio_legacy_query_dirty_bitmap(const VFIOContainerBase *bcontainer,
>                         VFIOBitmap *vbmap, hwaddr iova, hwaddr size, Error **errp)
>   {
> -    const VFIOContainer *container = container_of(bcontainer, VFIOContainer,
> -                                                  bcontainer);
> +    const VFIOContainer *container = VFIO_IOMMU_LEGACY(bcontainer);
>       struct vfio_iommu_type1_dirty_bitmap *dbitmap;
>       struct vfio_iommu_type1_dirty_bitmap_get *range;
>       int ret;
> @@ -495,7 +491,7 @@ static void vfio_get_iommu_info_migration(VFIOContainer *container,
>   {
>       struct vfio_info_cap_header *hdr;
>       struct vfio_iommu_type1_info_cap_migration *cap_mig;
> -    VFIOContainerBase *bcontainer = &container->bcontainer;
> +    VFIOContainerBase *bcontainer = VFIO_IOMMU(container);
>   
>       hdr = vfio_get_iommu_info_cap(info, VFIO_IOMMU_TYPE1_INFO_CAP_MIGRATION);
>       if (!hdr) {
> @@ -518,8 +514,7 @@ static void vfio_get_iommu_info_migration(VFIOContainer *container,
>   
>   static bool vfio_legacy_setup(VFIOContainerBase *bcontainer, Error **errp)
>   {
> -    VFIOContainer *container = container_of(bcontainer, VFIOContainer,
> -                                            bcontainer);
> +    VFIOContainer *container = VFIO_IOMMU_LEGACY(bcontainer);
>       g_autofree struct vfio_iommu_type1_info *info = NULL;
>       int ret;
>   
> @@ -634,7 +629,7 @@ static bool vfio_container_connect(VFIOGroup *group, AddressSpace *as,
>   
>       if (!cpr_is_incoming()) {
>           QLIST_FOREACH(bcontainer, &space->containers, next) {
> -            container = container_of(bcontainer, VFIOContainer, bcontainer);
> +            container = VFIO_IOMMU_LEGACY(bcontainer);
>               if (!ioctl(group->fd, VFIO_GROUP_SET_CONTAINER, &container->fd)) {
>                   return vfio_container_group_add(container, group, errp);
>               }
> @@ -652,7 +647,7 @@ static bool vfio_container_connect(VFIOGroup *group, AddressSpace *as,
>            * create the container struct and group list.
>            */
>           QLIST_FOREACH(bcontainer, &space->containers, next) {
> -            container = container_of(bcontainer, VFIOContainer, bcontainer);
> +            container = VFIO_IOMMU_LEGACY(bcontainer);
>   
>               if (vfio_cpr_container_match(container, group, fd)) {
>                   return vfio_container_group_add(container, group, errp);
> @@ -672,7 +667,7 @@ static bool vfio_container_connect(VFIOGroup *group, AddressSpace *as,
>           goto fail;
>       }
>       new_container = true;
> -    bcontainer = &container->bcontainer;
> +    bcontainer = VFIO_IOMMU(container);
>   
>       if (!vfio_legacy_cpr_register_container(container, errp)) {
>           goto fail;
> @@ -735,7 +730,7 @@ fail:
>   static void vfio_container_disconnect(VFIOGroup *group)
>   {
>       VFIOContainer *container = group->container;
> -    VFIOContainerBase *bcontainer = &container->bcontainer;
> +    VFIOContainerBase *bcontainer = VFIO_IOMMU(container);
>       VFIOIOMMUClass *vioc = VFIO_IOMMU_GET_CLASS(bcontainer);
>   
>       QLIST_REMOVE(group, container_next);
> @@ -781,7 +776,7 @@ static VFIOGroup *vfio_group_get(int groupid, AddressSpace *as, Error **errp)
>       QLIST_FOREACH(group, &vfio_group_list, next) {
>           if (group->groupid == groupid) {
>               /* Found it.  Now is it already in the right context? */
> -            if (group->container->bcontainer.space->as == as) {
> +            if (VFIO_IOMMU(group->container)->space->as == as) {
>                   return group;
>               } else {
>                   error_setg(errp, "group %d used in multiple address spaces",
> @@ -895,7 +890,7 @@ static bool vfio_device_get(VFIOGroup *group, const char *name,
>           }
>       }
>   
> -    vfio_device_prepare(vbasedev, &group->container->bcontainer, info);
> +    vfio_device_prepare(vbasedev, VFIO_IOMMU(group->container), info);
>   
>       vbasedev->fd = fd;
>       vbasedev->group = group;