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

[Juergen Gross <jgross@xxxxxxxx>]

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>
---
 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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