Re: [PATCH v4 10/12] vfio/iommufd: Implement VFIOIOMMUClass::query_dirty_bitmap support

[Eric Auger]

On 7/12/24 13:47, Joao Martins wrote:
> ioctl(iommufd, IOMMU_HWPT_GET_DIRTY_BITMAP, arg) is the UAPI
> that fetches the bitmap that tells what was dirty in an IOVA
> range.
>
> A single bitmap is allocated and used across all the hwpts
> sharing an IOAS which is then used in log_sync() to set Qemu
> global bitmaps.
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Eric
>
> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
> ---
>  include/sysemu/iommufd.h |  4 ++++
>  backends/iommufd.c       | 29 +++++++++++++++++++++++++++++
>  hw/vfio/iommufd.c        | 27 +++++++++++++++++++++++++++
>  backends/trace-events    |  1 +
>  4 files changed, 61 insertions(+)
>
> diff --git a/include/sysemu/iommufd.h b/include/sysemu/iommufd.h
> index 7416d9219703..869ca8b7ef59 100644
> --- a/include/sysemu/iommufd.h
> +++ b/include/sysemu/iommufd.h
> @@ -57,6 +57,10 @@ bool iommufd_backend_alloc_hwpt(IOMMUFDBackend *be, 
> uint32_t dev_id,
>                                  Error **errp);
>  bool iommufd_backend_set_dirty_tracking(IOMMUFDBackend *be, uint32_t hwpt_id,
>                                          bool start, Error **errp);
> +bool iommufd_backend_get_dirty_bitmap(IOMMUFDBackend *be, uint32_t hwpt_id,
> +                                      uint64_t iova, ram_addr_t size,
> +                                      uint64_t page_size, uint64_t *data,
> +                                      Error **errp);
>  
>  #define TYPE_HOST_IOMMU_DEVICE_IOMMUFD TYPE_HOST_IOMMU_DEVICE "-iommufd"
>  
> diff --git a/backends/iommufd.c b/backends/iommufd.c
> index 239f0976e0ad..46be719cae71 100644
> --- a/backends/iommufd.c
> +++ b/backends/iommufd.c
> @@ -262,6 +262,35 @@ bool iommufd_backend_set_dirty_tracking(IOMMUFDBackend 
> *be,
>      return true;
>  }
>  
> +bool iommufd_backend_get_dirty_bitmap(IOMMUFDBackend *be,
> +                                      uint32_t hwpt_id,
> +                                      uint64_t iova, ram_addr_t size,
> +                                      uint64_t page_size, uint64_t *data,
> +                                      Error **errp)
> +{
> +    int ret;
> +    struct iommu_hwpt_get_dirty_bitmap get_dirty_bitmap = {
> +        .size = sizeof(get_dirty_bitmap),
> +        .hwpt_id = hwpt_id,
> +        .iova = iova,
> +        .length = size,
> +        .page_size = page_size,
> +        .data = (uintptr_t)data,
> +    };
> +
> +    ret = ioctl(be->fd, IOMMU_HWPT_GET_DIRTY_BITMAP, &get_dirty_bitmap);
> +    trace_iommufd_backend_get_dirty_bitmap(be->fd, hwpt_id, iova, size,
> +                                           page_size, ret ? errno : 0);
> +    if (ret) {
> +        error_setg_errno(errp, errno,
> +                         "IOMMU_HWPT_GET_DIRTY_BITMAP (iova: 0x%"HWADDR_PRIx
> +                         " size: 0x%"HWADDR_PRIx") failed", iova, size);
> +        return false;
> +    }
> +
> +    return true;
> +}
> +
>  bool iommufd_backend_get_device_info(IOMMUFDBackend *be, uint32_t devid,
>                                       uint32_t *type, void *data, uint32_t 
> len,
>                                       uint64_t *caps, Error **errp)
> diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
> index da678315faeb..1fd1558fa0c0 100644
> --- a/hw/vfio/iommufd.c
> +++ b/hw/vfio/iommufd.c
> @@ -25,6 +25,7 @@
>  #include "qemu/cutils.h"
>  #include "qemu/chardev_open.h"
>  #include "pci.h"
> +#include "exec/ram_addr.h"
>  
>  static int iommufd_cdev_map(const VFIOContainerBase *bcontainer, hwaddr iova,
>                              ram_addr_t size, void *vaddr, bool readonly)
> @@ -146,6 +147,31 @@ err:
>      return -EINVAL;
>  }
>  
> +static int iommufd_query_dirty_bitmap(const VFIOContainerBase *bcontainer,
> +                                      VFIOBitmap *vbmap, hwaddr iova,
> +                                      hwaddr size, Error **errp)
> +{
> +    VFIOIOMMUFDContainer *container = container_of(bcontainer,
> +                                                   VFIOIOMMUFDContainer,
> +                                                   bcontainer);
> +    unsigned long page_size = qemu_real_host_page_size();
> +    VFIOIOASHwpt *hwpt;
> +
> +    QLIST_FOREACH(hwpt, &container->hwpt_list, next) {
> +        if (!iommufd_hwpt_dirty_tracking(hwpt)) {
> +            continue;
> +        }
> +
> +        if (!iommufd_backend_get_dirty_bitmap(container->be, hwpt->hwpt_id,
> +                                              iova, size, page_size,
> +                                              vbmap->bitmap, errp)) {
> +            return -EINVAL;
> +        }
> +    }
> +
> +    return 0;
> +}
> +
>  static int iommufd_cdev_getfd(const char *sysfs_path, Error **errp)
>  {
>      ERRP_GUARD();
> @@ -754,6 +780,7 @@ static void vfio_iommu_iommufd_class_init(ObjectClass 
> *klass, void *data)
>      vioc->detach_device = iommufd_cdev_detach;
>      vioc->pci_hot_reset = iommufd_cdev_pci_hot_reset;
>      vioc->set_dirty_page_tracking = iommufd_set_dirty_page_tracking;
> +    vioc->query_dirty_bitmap = iommufd_query_dirty_bitmap;
>  };
>  
>  static bool hiod_iommufd_vfio_realize(HostIOMMUDevice *hiod, void *opaque,
> diff --git a/backends/trace-events b/backends/trace-events
> index 28aca3b859d4..40811a316215 100644
> --- a/backends/trace-events
> +++ b/backends/trace-events
> @@ -17,3 +17,4 @@ iommufd_backend_alloc_ioas(int iommufd, uint32_t ioas) " 
> iommufd=%d ioas=%d"
>  iommufd_backend_alloc_hwpt(int iommufd, uint32_t dev_id, uint32_t pt_id, 
> uint32_t flags, uint32_t hwpt_type, uint32_t len, uint64_t data_ptr, uint32_t 
> out_hwpt_id, int ret) " iommufd=%d dev_id=%u pt_id=%u flags=0x%x hwpt_type=%u 
> len=%u data_ptr=0x%"PRIx64" out_hwpt=%u (%d)"
>  iommufd_backend_free_id(int iommufd, uint32_t id, int ret) " iommufd=%d 
> id=%d (%d)"
>  iommufd_backend_set_dirty(int iommufd, uint32_t hwpt_id, bool start, int 
> ret) " iommufd=%d hwpt=%u enable=%d (%d)"
> +iommufd_backend_get_dirty_bitmap(int iommufd, uint32_t hwpt_id, uint64_t 
> iova, uint64_t size, uint64_t page_size, int ret) " iommufd=%d hwpt=%u 
> iova=0x%"PRIx64" size=0x%"PRIx64" page_size=0x%"PRIx64" (%d)"