On Tue, Oct 10, 2023 at 5:05 PM Si-Wei Liu <si-wei.liu@xxxxxxxxxx> wrote:
>
> Devices with on-chip IOMMU or vendor specific IOTLB implementation
> may need to restore iotlb mapping to the initial or default state
> using the .reset_map op, as it's desirable for some parent devices
> to solely manipulate mappings by its own, independent of virtio device
> state. For instance, device reset does not cause mapping go away on
> such IOTLB model in need of persistent mapping. Before vhost-vdpa
> is going away, give them a chance to reset iotlb back to the initial
> state in vhost_vdpa_cleanup().
>
> Signed-off-by: Si-Wei Liu <si-wei.liu@xxxxxxxxxx>
> ---
> drivers/vhost/vdpa.c | 16 ++++++++++++++++
> 1 file changed, 16 insertions(+)
>
> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> index 851535f..a3f8160 100644
> --- a/drivers/vhost/vdpa.c
> +++ b/drivers/vhost/vdpa.c
> @@ -131,6 +131,15 @@ static struct vhost_vdpa_as *vhost_vdpa_find_alloc_as(struct vhost_vdpa *v,
> return vhost_vdpa_alloc_as(v, asid);
> }
>
> +static void vhost_vdpa_reset_map(struct vhost_vdpa *v, u32 asid)
> +{
> + struct vdpa_device *vdpa = v->vdpa;
> + const struct vdpa_config_ops *ops = vdpa->config;
> +
> + if (ops->reset_map)
> + ops->reset_map(vdpa, asid);
> +}
> +
> static int vhost_vdpa_remove_as(struct vhost_vdpa *v, u32 asid)
> {
> struct vhost_vdpa_as *as = asid_to_as(v, asid);
> @@ -140,6 +149,13 @@ static int vhost_vdpa_remove_as(struct vhost_vdpa *v, u32 asid)
>
> hlist_del(&as->hash_link);
> vhost_vdpa_iotlb_unmap(v, &as->iotlb, 0ULL, 0ULL - 1, asid);
> + /*
> + * Devices with vendor specific IOMMU may need to restore
> + * iotlb to the initial or default state which is not done
> + * through device reset, as the IOTLB mapping manipulation
> + * could be decoupled from the virtio device life cycle.
> + */
Should we do this according to whether IOTLB_PRESIST is set? Otherwise
we may break old userspace.
Thanks
> + vhost_vdpa_reset_map(v, asid);
> kfree(as);
>
> return 0;
> --
> 1.8.3.1
>
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