libxl,libxc: introduce libxl_get_numainfo()

Make some NUMA node information available to the toolstack. Achieve
this by means of xc_numainfo(), which exposes memory size and amount
of free memory of each node, as well as the relative distances of
each node to all the others.

For properly exposing distances we need the IDL to support arrays.

Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Committed-by: Ian Campbell <ian.campbell@citrix.com>

6 files changed, 118 insertions, 0 deletions

diff --git a/tools/libxc/xc_misc.c b/tools/libxc/xc_misc.c
index 812b127ff3..3c5d64a4d1 100644
--- a/tools/libxc/xc_misc.c
+++ b/tools/libxc/xc_misc.c
@@ -35,6 +35,20 @@ int xc_get_max_cpus(xc_interface *xch)
     return max_cpus;
 }
 
+int xc_get_max_nodes(xc_interface *xch)
+{
+    static int max_nodes = 0;
+    xc_physinfo_t physinfo;
+
+    if ( max_nodes )
+        return max_nodes;
+
+    if ( !xc_physinfo(xch, &physinfo) )
+        max_nodes = physinfo.max_node_id + 1;
+
+    return max_nodes;
+}
+
 int xc_get_cpumap_size(xc_interface *xch)
 {
     return (xc_get_max_cpus(xch) + 7) / 8;
diff --git a/tools/libxc/xenctrl.h b/tools/libxc/xenctrl.h
index 15bf8d28cb..91fbb02979 100644
--- a/tools/libxc/xenctrl.h
+++ b/tools/libxc/xenctrl.h
@@ -329,6 +329,12 @@ int xc_get_cpumap_size(xc_interface *xch);
 /* allocate a cpumap */
 xc_cpumap_t xc_cpumap_alloc(xc_interface *xch);
 
+ /*
+ * NODEMAP handling
+ */
+/* return maximum number of NUMA nodes the hypervisor supports */
+int xc_get_max_nodes(xc_interface *xch);
+
 /*
  * DOMAIN DEBUGGING FUNCTIONS
  */
diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index 9f301a9098..2ecdce3efd 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -3298,6 +3298,75 @@ fail:
     return ret;
 }
 
+libxl_numainfo *libxl_get_numainfo(libxl_ctx *ctx, int *nr)
+{
+    GC_INIT(ctx);
+    xc_numainfo_t ninfo;
+    DECLARE_HYPERCALL_BUFFER(xc_node_to_memsize_t, memsize);
+    DECLARE_HYPERCALL_BUFFER(xc_node_to_memfree_t, memfree);
+    DECLARE_HYPERCALL_BUFFER(uint32_t, node_dists);
+    libxl_numainfo *ret = NULL;
+    int i, j, max_nodes;
+
+    max_nodes = libxl_get_max_nodes(ctx);
+    if (max_nodes == 0)
+    {
+        LIBXL__LOG(ctx, XTL_ERROR, "Unable to determine number of NODES");
+        ret = NULL;
+        goto out;
+    }
+
+    memsize = xc_hypercall_buffer_alloc
+        (ctx->xch, memsize, sizeof(*memsize) * max_nodes);
+    memfree = xc_hypercall_buffer_alloc
+        (ctx->xch, memfree, sizeof(*memfree) * max_nodes);
+    node_dists = xc_hypercall_buffer_alloc
+        (ctx->xch, node_dists, sizeof(*node_dists) * max_nodes * max_nodes);
+    if ((memsize == NULL) || (memfree == NULL) || (node_dists == NULL)) {
+        LIBXL__LOG_ERRNOVAL(ctx, XTL_ERROR, ENOMEM,
+                            "Unable to allocate hypercall arguments");
+        goto fail;
+    }
+
+    set_xen_guest_handle(ninfo.node_to_memsize, memsize);
+    set_xen_guest_handle(ninfo.node_to_memfree, memfree);
+    set_xen_guest_handle(ninfo.node_to_node_distance, node_dists);
+    ninfo.max_node_index = max_nodes - 1;
+    if (xc_numainfo(ctx->xch, &ninfo) != 0) {
+        LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR, "getting numainfo");
+        goto fail;
+    }
+
+    if (ninfo.max_node_index < max_nodes - 1)
+        max_nodes = ninfo.max_node_index + 1;
+
+    *nr = max_nodes;
+
+    ret = libxl__zalloc(NOGC, sizeof(libxl_numainfo) * max_nodes);
+    for (i = 0; i < max_nodes; i++)
+        ret[i].dists = libxl__calloc(NOGC, max_nodes, sizeof(*node_dists));
+
+    for (i = 0; i < max_nodes; i++) {
+#define V(mem, i) (mem[i] == INVALID_NUMAINFO_ID) ? \
+    LIBXL_NUMAINFO_INVALID_ENTRY : mem[i]
+        ret[i].size = V(memsize, i);
+        ret[i].free = V(memfree, i);
+        ret[i].num_dists = max_nodes;
+        for (j = 0; j < ret[i].num_dists; j++)
+            ret[i].dists[j] = V(node_dists, i * max_nodes + j);
+#undef V
+    }
+
+ fail:
+    xc_hypercall_buffer_free(ctx->xch, memsize);
+    xc_hypercall_buffer_free(ctx->xch, memfree);
+    xc_hypercall_buffer_free(ctx->xch, node_dists);
+
+ out:
+    GC_FREE;
+    return ret;
+}
+
 const libxl_version_info* libxl_get_version_info(libxl_ctx *ctx)
 {
     union {
diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
index 371b659434..cb18eda9d5 100644
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -532,6 +532,9 @@ int libxl_domain_preserve(libxl_ctx *ctx, uint32_t domid, libxl_domain_create_in
 /* get max. number of cpus supported by hypervisor */
 int libxl_get_max_cpus(libxl_ctx *ctx);
 
+/* get max. number of NUMA nodes supported by hypervisor */
+int libxl_get_max_nodes(libxl_ctx *ctx);
+
 int libxl_domain_rename(libxl_ctx *ctx, uint32_t domid,
                         const char *old_name, const char *new_name);
 
@@ -604,6 +607,10 @@ void libxl_vminfo_list_free(libxl_vminfo *list, int nb_vm);
 libxl_cputopology *libxl_get_cpu_topology(libxl_ctx *ctx, int *nb_cpu_out);
 void libxl_cputopology_list_free(libxl_cputopology *, int nb_cpu);
 
+#define LIBXL_NUMAINFO_INVALID_ENTRY (~(uint32_t)0)
+libxl_numainfo *libxl_get_numainfo(libxl_ctx *ctx, int *nr);
+void libxl_numainfo_list_free(libxl_numainfo *, int nr);
+
 libxl_vcpuinfo *libxl_list_vcpu(libxl_ctx *ctx, uint32_t domid,
                                 int *nb_vcpu, int *nr_vcpus_out);
 void libxl_vcpuinfo_list_free(libxl_vcpuinfo *, int nr_vcpus);
diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
index 00947e1875..2735ebd82a 100644
--- a/tools/libxl/libxl_types.idl
+++ b/tools/libxl/libxl_types.idl
@@ -433,6 +433,15 @@ libxl_physinfo = Struct("physinfo", [
     ("cap_hvm_directio", bool),
     ], dir=DIR_OUT)
 
+# NUMA node characteristics: size and free are how much memory it has, and how
+# much of it is free, respectively. dists is an array of distances from this
+# node to each other node.
+libxl_numainfo = Struct("numainfo", [
+    ("size", uint64),
+    ("free", uint64),
+    ("dists", Array(uint32, "num_dists")),
+    ], dir=DIR_OUT)
+
 libxl_cputopology = Struct("cputopology", [
     ("core", uint32),
     ("socket", uint32),
diff --git a/tools/libxl/libxl_utils.c b/tools/libxl/libxl_utils.c
index f69a24c267..29f430d977 100644
--- a/tools/libxl/libxl_utils.c
+++ b/tools/libxl/libxl_utils.c
@@ -572,6 +572,11 @@ int libxl_get_max_cpus(libxl_ctx *ctx)
     return xc_get_max_cpus(ctx->xch);
 }
 
+int libxl_get_max_nodes(libxl_ctx *ctx)
+{
+    return xc_get_max_nodes(ctx->xch);
+}
+
 int libxl__enum_from_string(const libxl_enum_string_table *t,
                             const char *s, int *e)
 {
@@ -594,6 +599,14 @@ void libxl_cputopology_list_free(libxl_cputopology *list, int nr)
     free(list);
 }
 
+void libxl_numainfo_list_free(libxl_numainfo *list, int nr)
+{
+    int i;
+    for (i = 0; i < nr; i++)
+        libxl_numainfo_dispose(&list[i]);
+    free(list);
+}
+
 void libxl_vcpuinfo_list_free(libxl_vcpuinfo *list, int nr)
 {
     int i;