On Wed, 2015-09-30 at 20:26 +0530, Bharat Bhushan wrote:
> This patch allows the user-space to know whether msi-pages
> are automatically mapped with some magic iova or not.
>
> Even if the msi-pages are automatically mapped, still user-space
> wants to over-ride the automatic iova selection for msi-mapping.
> For this user-space need to know whether it is allowed to change
> the automatic mapping or not and this API provides this mechanism.
> Follow up patches will provide how to over-ride this.
>
> Signed-off-by: Bharat Bhushan <Bharat.Bhushan@xxxxxxxxxxxxx>
> ---
> drivers/vfio/vfio_iommu_type1.c | 32 ++++++++++++++++++++++++++++++++
> include/uapi/linux/vfio.h | 3 +++
> 2 files changed, 35 insertions(+)
>
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index fa5d3e4..3315fb6 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -59,6 +59,7 @@ struct vfio_iommu {
> struct rb_root dma_list;
> bool v2;
> bool nesting;
> + bool allow_msi_reconfig;
> struct list_head reserved_iova_list;
> };
>
> @@ -1117,6 +1118,23 @@ static int vfio_domains_have_iommu_cache(struct vfio_iommu *iommu)
> return ret;
> }
>
> +static
> +int vfio_domains_get_msi_maps(struct vfio_iommu *iommu,
> + struct iommu_domain_msi_maps *msi_maps)
> +{
> + struct vfio_domain *d;
> + int ret;
> +
> + mutex_lock(&iommu->lock);
> + /* All domains have same msi-automap property, pick first */
> + d = list_first_entry(&iommu->domain_list, struct vfio_domain, next);
> + ret = iommu_domain_get_attr(d->domain, DOMAIN_ATTR_MSI_MAPPING,
> + msi_maps);
> + mutex_unlock(&iommu->lock);
> +
> + return ret;
> +}
> +
> static long vfio_iommu_type1_ioctl(void *iommu_data,
> unsigned int cmd, unsigned long arg)
> {
> @@ -1138,6 +1156,8 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
> }
> } else if (cmd == VFIO_IOMMU_GET_INFO) {
> struct vfio_iommu_type1_info info;
> + struct iommu_domain_msi_maps msi_maps;
> + int ret;
>
> minsz = offsetofend(struct vfio_iommu_type1_info, iova_pgsizes);
>
> @@ -1149,6 +1169,18 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
>
> info.flags = 0;
>
> + ret = vfio_domains_get_msi_maps(iommu, &msi_maps);
> + if (ret)
> + return ret;
And now ioctl(VFIO_IOMMU_GET_INFO) no longer works for any IOMMU
implementing domain_get_attr but not supporting DOMAIN_ATTR_MSI_MAPPING.
> +
> + if (msi_maps.override_automap) {
> + info.flags |= VFIO_IOMMU_INFO_MSI_ALLOW_RECONFIG;
> + iommu->allow_msi_reconfig = true;
> + }
> +
> + if (msi_maps.automap)
> + info.flags |= VFIO_IOMMU_INFO_MSI_AUTOMAP;
> +
> info.iova_pgsizes = vfio_pgsize_bitmap(iommu);
>
> return copy_to_user((void __user *)arg, &info, minsz);
> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> index 1abd1a9..9998f6e 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -391,6 +391,9 @@ struct vfio_iommu_type1_info {
> __u32 argsz;
> __u32 flags;
> #define VFIO_IOMMU_INFO_PGSIZES (1 << 0) /* supported page sizes info */
> +#define VFIO_IOMMU_INFO_MSI_AUTOMAP (1 << 1) /* MSI pages are auto-mapped
> + in iommu */
> +#define VFIO_IOMMU_INFO_MSI_ALLOW_RECONFIG (1 << 2) /* Allows reconfig automap*/
> __u64 iova_pgsizes; /* Bitmap of supported page sizes */
> };
>
Once again, exposing interfaces to the user before they actually do
anything is backwards.
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