[PATCH 2/4] libxc: report how much memory a domain has on each NUMA node

[Dario Faggioli <dario.faggioli@citrix.com>]

by means of a new interface: xc_domain_numainfo().

The caller is expected to allocate an array for the call to fill,
with the results of the XEN_DOMCTL_numainfo hypercall. The size of
the array is also passed to the function, which then returns back
the number of elements that have actually been filled by Xen.

Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com>
---
 tools/libxc/xc_domain.c |   28 ++++++++++++++++++++++++++++
 tools/libxc/xenctrl.h   |   18 ++++++++++++++++++
 2 files changed, 46 insertions(+)

diff --git a/tools/libxc/xc_domain.c b/tools/libxc/xc_domain.c
index 369c3f3..a2b3c07 100644
--- a/tools/libxc/xc_domain.c
+++ b/tools/libxc/xc_domain.c
@@ -362,6 +362,34 @@ int xc_domain_getinfo(xc_interface *xch,
     return nr_doms;
 }
 
+int xc_domain_numainfo(xc_interface *xch, uint32_t domid,
+                       int *max_nodes, uint64_t *memkbs)
+{
+    DECLARE_DOMCTL;
+    DECLARE_HYPERCALL_BOUNCE(memkbs, sizeof(uint64_t) * (*max_nodes),
+                             XC_HYPERCALL_BUFFER_BOUNCE_OUT);
+    int ret = 0;
+
+    if ( xc_hypercall_bounce_pre(xch, memkbs) )
+    {
+        PERROR("Could not allocate bounce buffer for DOMCTL_domain_numainfo");
+        return -1;
+    }
+
+    domctl.cmd = XEN_DOMCTL_numainfo;
+    domctl.domain = (domid_t)domid;
+    domctl.u.numainfo.max_node_index = *max_nodes - 1;
+    set_xen_guest_handle(domctl.u.numainfo.memkb_on_node, memkbs);
+
+    ret = do_domctl(xch, &domctl);
+
+    *max_nodes = domctl.u.numainfo.max_node_index + 1;
+
+    xc_hypercall_bounce_post(xch, memkbs);
+
+    return ret;
+}
+
 int xc_domain_getinfolist(xc_interface *xch,
                           uint32_t first_domain,
                           unsigned int max_domains,
diff --git a/tools/libxc/xenctrl.h b/tools/libxc/xenctrl.h
index 13f816b..845d183 100644
--- a/tools/libxc/xenctrl.h
+++ b/tools/libxc/xenctrl.h
@@ -657,6 +657,24 @@ int xc_domain_getinfolist(xc_interface *xch,
                           xc_domaininfo_t *info);
 
 /**
+ * This function tells how much memory a domain has allocated on each
+ * online NUMA node of the host. The information is stored in an array
+ * that the caller provides, along with its size. The function updates
+ * the latter parameter with the number of elements in the array that
+ * have been actually filled.
+ *
+ * @param xch a handle to an open hypervisor interface
+ * @param domid the domain id for which we want the information
+ * @param max_nodes as an input, the size of the memkbs array; as an
+ *                  output, the number of filled elements in it
+ * @param memkbs an array with, in the i-eth element, the memory, in
+ *               Kb, allocated for the domain on the i-eth NUMA node
+ * @return 0 on success, -1 on failure
+ */
+int xc_domain_numainfo(xc_interface *xch, uint32_t domid,
+                       int *max_nodes, uint64_t *memkbs);
+
+/**
  * This function set p2m for broken page
  * &parm xch a handle to an open hypervisor interface
  * @parm domid the domain id which broken page belong to