Re: [PATCH Kernel v18 6/7] vfio iommu: Add migration capability to report supported features

[Alex Williamson]

On Mon, 4 May 2020 21:28:58 +0530
Kirti Wankhede <address@hidden> wrote:

> Added migration capability in IOMMU info chain.
> User application should check IOMMU info chain for migration capability
> to use dirty page tracking feature provided by kernel module.
> 
> Signed-off-by: Kirti Wankhede <address@hidden>
> ---
>  drivers/vfio/vfio_iommu_type1.c | 15 +++++++++++++++
>  include/uapi/linux/vfio.h       | 14 ++++++++++++++
>  2 files changed, 29 insertions(+)
> 
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index 8b27faf1ec38..b38d278d7bff 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -2378,6 +2378,17 @@ static int vfio_iommu_iova_build_caps(struct 
> vfio_iommu *iommu,
>       return ret;
>  }
>  
> +static int vfio_iommu_migration_build_caps(struct vfio_info_cap *caps)
> +{
> +     struct vfio_iommu_type1_info_cap_migration cap_mig;
> +
> +     cap_mig.header.id = VFIO_IOMMU_TYPE1_INFO_CAP_MIGRATION;
> +     cap_mig.header.version = 1;
> +     cap_mig.flags = VFIO_IOMMU_INFO_CAPS_MIGRATION_DIRTY_PAGE_TRACK;
> +
> +     return vfio_info_add_capability(caps, &cap_mig.header, sizeof(cap_mig));
> +}
> +
>  static long vfio_iommu_type1_ioctl(void *iommu_data,
>                                  unsigned int cmd, unsigned long arg)
>  {
> @@ -2427,6 +2438,10 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
>               if (ret)
>                       return ret;
>  
> +             ret = vfio_iommu_migration_build_caps(&caps);
> +             if (ret)
> +                     return ret;
> +
>               if (caps.size) {
>                       info.flags |= VFIO_IOMMU_INFO_CAPS;
>  
> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> index e3cbf8b78623..df9ce8aaafab 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -1013,6 +1013,20 @@ struct vfio_iommu_type1_info_cap_iova_range {
>       struct  vfio_iova_range iova_ranges[];
>  };
>  
> +/*
> + * The migration capability allows to report supported features for 
> migration.
> + *
> + * The structures below define version 1 of this capability.
> + */
> +#define VFIO_IOMMU_TYPE1_INFO_CAP_MIGRATION  1
> +
> +struct vfio_iommu_type1_info_cap_migration {
> +     struct  vfio_info_cap_header header;
> +     __u32   flags;
> +     /* supports dirty page tracking */
> +#define VFIO_IOMMU_INFO_CAPS_MIGRATION_DIRTY_PAGE_TRACK      (1 << 0)
> +};
> +

What about exposing the maximum supported dirty bitmap size and the
supported page sizes?  Thanks,

Alex

>  #define VFIO_IOMMU_GET_INFO _IO(VFIO_TYPE, VFIO_BASE + 12)
>  
>  /**