Re: [Xen-devel] [PATCH v3 8/8] libxl: add libxl support for setting grant table resource limits

[Paul Durrant <Paul.Durrant@xxxxxxxxxx>]

> -----Original Message-----
> From: Xen-devel [mailto:xen-devel-bounces@xxxxxxxxxxxxx] On Behalf Of
> Juergen Gross
> Sent: 06 September 2017 13:47
> To: xen-devel@xxxxxxxxxxxxx
> Cc: Juergen Gross <jgross@xxxxxxxx>; sstabellini@xxxxxxxxxx; Wei Liu
> <wei.liu2@xxxxxxxxxx>; George Dunlap <George.Dunlap@xxxxxxxxxx>;
> Andrew Cooper <Andrew.Cooper3@xxxxxxxxxx>; Ian Jackson
> <Ian.Jackson@xxxxxxxxxx>; Tim (Xen.org) <tim@xxxxxxx>;
> julien.grall@xxxxxxx; jbeulich@xxxxxxxx
> Subject: [Xen-devel] [PATCH v3 8/8] libxl: add libxl support for setting grant
> table resource limits
> 
> Add new domain config items for setting the limits for the maximum
> numbers of grant table frames and maptrack frames of a domain.
> 
> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>

Reviewed-by: Paul Durrant <paul.durrant@xxxxxxxxxx>

> ---
>  docs/man/xl.cfg.pod.5.in    | 15 +++++++++++++++
>  tools/libxl/libxl.h         |  6 ++++++
>  tools/libxl/libxl_dom.c     |  8 ++++++++
>  tools/libxl/libxl_types.idl |  3 +++
>  tools/xl/xl_parse.c         |  5 +++++
>  tools/xl/xl_sxp.c           |  2 ++
>  6 files changed, 39 insertions(+)
> 
> diff --git a/docs/man/xl.cfg.pod.5.in b/docs/man/xl.cfg.pod.5.in
> index 79cb2eaea7..dd0b232020 100644
> --- a/docs/man/xl.cfg.pod.5.in
> +++ b/docs/man/xl.cfg.pod.5.in
> @@ -444,6 +444,21 @@ unpausing the domain. With a properly constructed
> security policy (such
>  as nomigrate_t in the example policy), this can be used to build a
>  domain whose memory is not accessible to the toolstack domain.
> 
> +=item B<grant_frames=NUMBER>
> +
> +Specify the maximum number of grant frames the domain is allowed to
> have.
> +This value controls how many pages the domain is able to grant access to for
> +other domains, needed e.g. for the operation of paravirtualized devices.
> +The default is 32, if not set to another value via a Xen boot parameter.
> +
> +=item B<maptrack_frames=NUMBER>
> +
> +Specify the maximum number of grant maptrack frames the domain is
> allowed
> +to have. This value controls how many pages of foreign domains can be
> accessed
> +via the grant mechanism by this domain. A value higher than the normal
> default
> +of 1024 is normally needed only for very large configurations for driver
> +domains.
> +
>  =item B<nomigrate=BOOLEAN>
> 
>  Disable migration of this domain.  This enables certain other features
> diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
> index 812b7ea95d..fef22c2306 100644
> --- a/tools/libxl/libxl.h
> +++ b/tools/libxl/libxl.h
> @@ -311,6 +311,12 @@
>  #define LIBXL_HAVE_P9S 1
> 
>  /*
> + * LIBXL_HAVE_BUILDINFO_GRANT_LIMITS indicates that
> libxl_domain_build_info
> + * has the grant_frames and maptrack_frames fields.
> + */
> +#define LIBXL_HAVE_BUILDINFO_GRANT_LIMITS 1
> +
> +/*
>   * libxl ABI compatibility
>   *
>   * The only guarantee which libxl makes regarding ABI compatibility
> diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c
> index f54fd49a73..080335874e 100644
> --- a/tools/libxl/libxl_dom.c
> +++ b/tools/libxl/libxl_dom.c
> @@ -322,6 +322,14 @@ int libxl__build_pre(libxl__gc *gc, uint32_t domid,
>          return ERROR_FAIL;
>      }
> 
> +    if (info->grant_frames || info->maptrack_frames) {
> +        if (xc_domain_set_gnttab_limits(ctx->xch, domid, info->grant_frames,
> +                                        info->maptrack_frames) != 0) {
> +            LOG(ERROR, "Couldn't set grant table limits");
> +            return ERROR_FAIL;
> +        }
> +    }
> +
>      /*
>       * Check if the domain has any CPU or node affinity already. If not, try
>       * to build up the latter via automatic NUMA placement. In fact, in case
> diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
> index 173d70acec..2aa7dae83e 100644
> --- a/tools/libxl/libxl_types.idl
> +++ b/tools/libxl/libxl_types.idl
> @@ -472,6 +472,9 @@ libxl_domain_build_info =
> Struct("domain_build_info",[
>      ("blkdev_start",    string),
> 
>      ("vnuma_nodes", Array(libxl_vnode_info, "num_vnuma_nodes")),
> +
> +    ("grant_frames",    uint32),
> +    ("maptrack_frames", uint32),
> 
>      ("device_model_version", libxl_device_model_version),
>      ("device_model_stubdomain", libxl_defbool),
> diff --git a/tools/xl/xl_parse.c b/tools/xl/xl_parse.c
> index 02ddd2e90d..dae3a238a4 100644
> --- a/tools/xl/xl_parse.c
> +++ b/tools/xl/xl_parse.c
> @@ -943,6 +943,11 @@ void parse_config_data(const char *config_source,
>          !xlu_cfg_get_string (config, "cpus_soft", &buf, 0))
>          parse_vcpu_affinity(b_info, cpus, buf, num_cpus, false);
> 
> +    if (!xlu_cfg_get_long (config, "grant_frames", &l, 0))
> +        b_info->grant_frames = l;
> +    if (!xlu_cfg_get_long (config, "maptrack_frames", &l, 0))
> +        b_info->maptrack_frames = l;
> +
>      libxl_defbool_set(&b_info->claim_mode, claim_mode);
> 
>      if (xlu_cfg_get_string (config, "on_poweroff", &buf, 0))
> diff --git a/tools/xl/xl_sxp.c b/tools/xl/xl_sxp.c
> index e738bf2465..4b2fab2d35 100644
> --- a/tools/xl/xl_sxp.c
> +++ b/tools/xl/xl_sxp.c
> @@ -64,6 +64,8 @@ void printf_info_sexp(int domid, libxl_domain_config
> *d_config, FILE *fh)
> 
>      fprintf(fh, "\t(build_info)\n");
>      fprintf(fh, "\t(max_vcpus %d)\n", b_info->max_vcpus);
> +    fprintf(fh, "\t(grant_frames %d)\n", b_info->grant_frames);
> +    fprintf(fh, "\t(maptrack_frames %d)\n", b_info->maptrack_frames);
>      fprintf(fh, "\t(tsc_mode %s)\n", libxl_tsc_mode_to_string(b_info-
> >tsc_mode));
>      fprintf(fh, "\t(max_memkb %"PRId64")\n", b_info->max_memkb);
>      fprintf(fh, "\t(target_memkb %"PRId64")\n", b_info->target_memkb);
> --
> 2.12.3
> 
> 
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