On Sun, 22 Mar 2020 05:32:00 -0700
"Liu, Yi L" <yi.l....@intel.com> wrote:

> From: Liu Yi L <yi.l....@intel.com>
> 
> This patch reports PASID alloc/free availability to userspace (e.g. QEMU)
> thus userspace could do a pre-check before utilizing this feature.
> 
> Cc: Kevin Tian <kevin.t...@intel.com>
> CC: Jacob Pan <jacob.jun....@linux.intel.com>
> Cc: Alex Williamson <alex.william...@redhat.com>
> Cc: Eric Auger <eric.au...@redhat.com>
> Cc: Jean-Philippe Brucker <jean-phili...@linaro.org>
> Signed-off-by: Liu Yi L <yi.l....@intel.com>
> ---
>  drivers/vfio/vfio_iommu_type1.c | 28 ++++++++++++++++++++++++++++
>  include/uapi/linux/vfio.h       |  8 ++++++++
>  2 files changed, 36 insertions(+)
> 
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index e40afc0..ddd1ffe 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -2234,6 +2234,30 @@ static int vfio_iommu_type1_pasid_free(struct 
> vfio_iommu *iommu,
>       return ret;
>  }
>  
> +static int vfio_iommu_info_add_nesting_cap(struct vfio_iommu *iommu,
> +                                      struct vfio_info_cap *caps)
> +{
> +     struct vfio_info_cap_header *header;
> +     struct vfio_iommu_type1_info_cap_nesting *nesting_cap;
> +
> +     header = vfio_info_cap_add(caps, sizeof(*nesting_cap),
> +                                VFIO_IOMMU_TYPE1_INFO_CAP_NESTING, 1);
> +     if (IS_ERR(header))
> +             return PTR_ERR(header);
> +
> +     nesting_cap = container_of(header,
> +                             struct vfio_iommu_type1_info_cap_nesting,
> +                             header);
> +
> +     nesting_cap->nesting_capabilities = 0;
> +     if (iommu->nesting) {
> +             /* nesting iommu type supports PASID requests (alloc/free) */
> +             nesting_cap->nesting_capabilities |= VFIO_IOMMU_PASID_REQS;
> +     }
> +
> +     return 0;
> +}
> +
>  static long vfio_iommu_type1_ioctl(void *iommu_data,
>                                  unsigned int cmd, unsigned long arg)
>  {
> @@ -2283,6 +2307,10 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
>               if (ret)
>                       return ret;
>  
> +             ret = vfio_iommu_info_add_nesting_cap(iommu, &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 298ac80..8837219 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -748,6 +748,14 @@ struct vfio_iommu_type1_info_cap_iova_range {
>       struct  vfio_iova_range iova_ranges[];
>  };
>  
> +#define VFIO_IOMMU_TYPE1_INFO_CAP_NESTING  2
> +
> +struct vfio_iommu_type1_info_cap_nesting {
> +     struct  vfio_info_cap_header header;
> +#define VFIO_IOMMU_PASID_REQS        (1 << 0)
> +     __u32   nesting_capabilities;
> +};
> +
>  #define VFIO_IOMMU_GET_INFO _IO(VFIO_TYPE, VFIO_BASE + 12)
>  
>  /**

I think this answers my PROBE question on patch 1/.  Should the
quota/usage be exposed to the user here?  Thanks,

Alex

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