Re: [PATCH v3 08/15] vfio: add unmap_all flag to DMA unmap callback

["Cédric Le Goater" <clg@redhat.com>]

On 5/7/25 17:20, John Levon wrote:
> We'll use this parameter shortly; this just adds the plumbing.
> 
> Signed-off-by: John Levon <john.levon@nutanix.com>


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

Thanks,

C.


> ---
>   include/hw/vfio/vfio-container-base.h | 15 +++++++++++++--
>   hw/vfio/container-base.c              |  4 ++--
>   hw/vfio/container.c                   |  8 ++++++--
>   hw/vfio/iommufd.c                     |  6 +++++-
>   hw/vfio/listener.c                    |  8 ++++----
>   5 files changed, 30 insertions(+), 11 deletions(-)
> 
> diff --git a/include/hw/vfio/vfio-container-base.h b/include/hw/vfio/vfio-container-base.h
> index 5527e02722..59f07d26e8 100644
> --- a/include/hw/vfio/vfio-container-base.h
> +++ b/include/hw/vfio/vfio-container-base.h
> @@ -81,7 +81,7 @@ int vfio_container_dma_map(VFIOContainerBase *bcontainer,
>                              void *vaddr, bool readonly);
>   int vfio_container_dma_unmap(VFIOContainerBase *bcontainer,
>                                hwaddr iova, ram_addr_t size,
> -                             IOMMUTLBEntry *iotlb);
> +                             IOMMUTLBEntry *iotlb, bool unmap_all);
>   bool vfio_container_add_section_window(VFIOContainerBase *bcontainer,
>                                          MemoryRegionSection *section,
>                                          Error **errp);
> @@ -120,9 +120,20 @@ struct VFIOIOMMUClass {
>       int (*dma_map)(const VFIOContainerBase *bcontainer,
>                      hwaddr iova, ram_addr_t size,
>                      void *vaddr, bool readonly);
> +    /**
> +     * @dma_unmap
> +     *
> +     * Unmap an address range from the container.
> +     *
> +     * @bcontainer: #VFIOContainerBase to use for unmap
> +     * @iova: start address to unmap
> +     * @size: size of the range to unmap
> +     * @iotlb: The IOMMU TLB mapping entry (or NULL)
> +     * @unmap_all: if set, unmap the entire address space
> +     */
>       int (*dma_unmap)(const VFIOContainerBase *bcontainer,
>                        hwaddr iova, ram_addr_t size,
> -                     IOMMUTLBEntry *iotlb);
> +                     IOMMUTLBEntry *iotlb, bool unmap_all);
>       bool (*attach_device)(const char *name, VFIODevice *vbasedev,
>                             AddressSpace *as, Error **errp);
>       void (*detach_device)(VFIODevice *vbasedev);
> diff --git a/hw/vfio/container-base.c b/hw/vfio/container-base.c
> index 09340fd97a..3ff473a45c 100644
> --- a/hw/vfio/container-base.c
> +++ b/hw/vfio/container-base.c
> @@ -85,12 +85,12 @@ int vfio_container_dma_map(VFIOContainerBase *bcontainer,
>   
>   int vfio_container_dma_unmap(VFIOContainerBase *bcontainer,
>                                hwaddr iova, ram_addr_t size,
> -                             IOMMUTLBEntry *iotlb)
> +                             IOMMUTLBEntry *iotlb, bool unmap_all)
>   {
>       VFIOIOMMUClass *vioc = VFIO_IOMMU_GET_CLASS(bcontainer);
>   
>       g_assert(vioc->dma_unmap);
> -    return vioc->dma_unmap(bcontainer, iova, size, iotlb);
> +    return vioc->dma_unmap(bcontainer, iova, size, iotlb, unmap_all);
>   }
>   
>   bool vfio_container_add_section_window(VFIOContainerBase *bcontainer,
> diff --git a/hw/vfio/container.c b/hw/vfio/container.c
> index cf23aa799f..d5f4e66f1c 100644
> --- a/hw/vfio/container.c
> +++ b/hw/vfio/container.c
> @@ -124,7 +124,7 @@ unmap_exit:
>    */
>   static int vfio_legacy_dma_unmap(const VFIOContainerBase *bcontainer,
>                                    hwaddr iova, ram_addr_t size,
> -                                 IOMMUTLBEntry *iotlb)
> +                                 IOMMUTLBEntry *iotlb, bool unmap_all)
>   {
>       const VFIOContainer *container = container_of(bcontainer, VFIOContainer,
>                                                     bcontainer);
> @@ -138,6 +138,10 @@ static int vfio_legacy_dma_unmap(const VFIOContainerBase *bcontainer,
>       int ret;
>       Error *local_err = NULL;
>   
> +    if (unmap_all) {
> +        return -ENOTSUP;
> +    }
> +
>       if (iotlb && vfio_container_dirty_tracking_is_started(bcontainer)) {
>           if (!vfio_container_devices_dirty_tracking_is_supported(bcontainer) &&
>               bcontainer->dirty_pages_supported) {
> @@ -205,7 +209,7 @@ static int vfio_legacy_dma_map(const VFIOContainerBase *bcontainer, hwaddr iova,
>        */
>       if (ioctl(container->fd, VFIO_IOMMU_MAP_DMA, &map) == 0 ||
>           (errno == EBUSY &&
> -         vfio_legacy_dma_unmap(bcontainer, iova, size, NULL) == 0 &&
> +         vfio_legacy_dma_unmap(bcontainer, iova, size, NULL, false) == 0 &&
>            ioctl(container->fd, VFIO_IOMMU_MAP_DMA, &map) == 0)) {
>           return 0;
>       }
> diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
> index 62ecb758f1..6b2764c044 100644
> --- a/hw/vfio/iommufd.c
> +++ b/hw/vfio/iommufd.c
> @@ -46,11 +46,15 @@ static int iommufd_cdev_map(const VFIOContainerBase *bcontainer, hwaddr iova,
>   
>   static int iommufd_cdev_unmap(const VFIOContainerBase *bcontainer,
>                                 hwaddr iova, ram_addr_t size,
> -                              IOMMUTLBEntry *iotlb)
> +                              IOMMUTLBEntry *iotlb, bool unmap_all)
>   {
>       const VFIOIOMMUFDContainer *container =
>           container_of(bcontainer, VFIOIOMMUFDContainer, bcontainer);
>   
> +    if (unmap_all) {
> +        return -ENOTSUP;
> +    }
> +
>       /* TODO: Handle dma_unmap_bitmap with iotlb args (migration) */
>       return iommufd_backend_unmap_dma(container->be,
>                                        container->ioas_id, iova, size);
> diff --git a/hw/vfio/listener.c b/hw/vfio/listener.c
> index 6f77e18a7a..c5183700db 100644
> --- a/hw/vfio/listener.c
> +++ b/hw/vfio/listener.c
> @@ -172,7 +172,7 @@ static void vfio_iommu_map_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
>           }
>       } else {
>           ret = vfio_container_dma_unmap(bcontainer, iova,
> -                                       iotlb->addr_mask + 1, iotlb);
> +                                       iotlb->addr_mask + 1, iotlb, false);
>           if (ret) {
>               error_setg(&local_err,
>                          "vfio_container_dma_unmap(%p, 0x%"HWADDR_PRIx", "
> @@ -201,7 +201,7 @@ static void vfio_ram_discard_notify_discard(RamDiscardListener *rdl,
>       int ret;
>   
>       /* Unmap with a single call. */
> -    ret = vfio_container_dma_unmap(bcontainer, iova, size , NULL);
> +    ret = vfio_container_dma_unmap(bcontainer, iova, size , NULL, false);
>       if (ret) {
>           error_report("%s: vfio_container_dma_unmap() failed: %s", __func__,
>                        strerror(-ret));
> @@ -638,7 +638,7 @@ static void vfio_listener_region_del(MemoryListener *listener,
>               /* The unmap ioctl doesn't accept a full 64-bit span. */
>               llsize = int128_rshift(llsize, 1);
>               ret = vfio_container_dma_unmap(bcontainer, iova,
> -                                           int128_get64(llsize), NULL);
> +                                           int128_get64(llsize), NULL, false);
>               if (ret) {
>                   error_report("vfio_container_dma_unmap(%p, 0x%"HWADDR_PRIx", "
>                                "0x%"HWADDR_PRIx") = %d (%s)",
> @@ -648,7 +648,7 @@ static void vfio_listener_region_del(MemoryListener *listener,
>               iova += int128_get64(llsize);
>           }
>           ret = vfio_container_dma_unmap(bcontainer, iova,
> -                                       int128_get64(llsize), NULL);
> +                                       int128_get64(llsize), NULL, false);
>           if (ret) {
>               error_report("vfio_container_dma_unmap(%p, 0x%"HWADDR_PRIx", "
>                            "0x%"HWADDR_PRIx") = %d (%s)",