Re: [Xen-devel] [PATCH v2 16/23] vixen: pass grant table operations through to the outer Xen

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Sun, Jan 07, 2018 at 12:28:32PM -0800, Anthony Liguori wrote:
>  static long
> +vixen_gnttab_setup_table(
> +    XEN_GUEST_HANDLE_PARAM(gnttab_setup_table_t) uop, unsigned int count)
> +{
> +    long rc;
> +
> +    struct gnttab_setup_table op;
> +    xen_pfn_t *frame_list = NULL;
> +    XEN_GUEST_HANDLE(xen_pfn_t) old_frame_list;
> +
> +    if ( count != 1 )
> +        return -EINVAL;
> +
> +    if ( unlikely(copy_from_guest(&op, uop, 1) != 0) )
> +    {
> +        gdprintk(XENLOG_INFO, "Fault while reading gnttab_setup_table_t.\n");
> +        return -EFAULT;
> +    }
> +
> +    if ( op.nr_frames > 0 ) {
> +        frame_list = xzalloc_array(xen_pfn_t, op.nr_frames);
> +        if ( frame_list == NULL )
> +            return -ENOMEM;
> +    }
> +
> +    old_frame_list = op.frame_list;
> +    op.frame_list.p = frame_list;
> +
> +    rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &op, count);
> +    op.frame_list = old_frame_list;

Are you sure this works? HVM based guests need to use
XENMAPSPACE_grant_table so that they map the grant table somewhere in
the p2m.

My comment was the other way around: you can ditch the
GNTTABOP_setup_table call, but you need to keep the
XENMAPSPACE_grant_table one.

>  long
>  do_grant_table_op(
>      unsigned int cmd, XEN_GUEST_HANDLE_PARAM(void) uop, unsigned int count)
> @@ -3324,6 +3422,9 @@ do_grant_table_op(
>      if ( (cmd &= GNTTABOP_CMD_MASK) != GNTTABOP_cache_flush && opaque_in )
>          return -EINVAL;
>  
> +    if ( is_vixen() )
> +        return vixen_do_grant_table_op(cmd, uop, count);

You seem to be missing the compat code.

Roger.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel