Add new domctl hypercall to expose current heap values. This

functionality is needed for probing how much memory is available in a
given node prior to VM creation.

Signed-off-by: Ryan Harper <ryanh@us.ibm.com>
Signed-off-by: Keir Fraser <keir@xensource.com>

2 files changed, 35 insertions, 0 deletions

diff --git a/tools/libxc/xc_domain.c b/tools/libxc/xc_domain.c
index 11c14247a2..485b260601 100644
--- a/tools/libxc/xc_domain.c
+++ b/tools/libxc/xc_domain.c
@@ -588,6 +588,27 @@ int xc_domain_ioport_permission(int xc_handle,
     return do_domctl(xc_handle, &domctl);
 }
 
+int xc_availheap(int xc_handle,
+                 int min_width,
+                 int max_width,
+                 int node,
+                 uint64_t *bytes)
+{
+    DECLARE_SYSCTL;
+    int rc;
+
+    sysctl.cmd = XEN_SYSCTL_availheap;
+    sysctl.u.availheap.min_bitwidth = min_width;
+    sysctl.u.availheap.max_bitwidth = max_width;
+    sysctl.u.availheap.node = node;
+
+    rc = xc_sysctl(xc_handle, &sysctl);
+
+    *bytes = sysctl.u.availheap.avail_bytes;
+
+    return rc;
+}
+
 int xc_vcpu_setcontext(int xc_handle,
                        uint32_t domid,
                        uint32_t vcpu,
diff --git a/tools/libxc/xenctrl.h b/tools/libxc/xenctrl.h
index 6ba6c8b034..93842d4f00 100644
--- a/tools/libxc/xenctrl.h
+++ b/tools/libxc/xenctrl.h
@@ -616,6 +616,20 @@ int xc_get_pfn_type_batch(int xc_handle, uint32_t dom,
 /* Get current total pages allocated to a domain. */
 long xc_get_tot_pages(int xc_handle, uint32_t domid);
 
+/**
+ * This function retrieves the the number of bytes available
+ * in the heap in a specific range of address-widths and nodes.
+ * 
+ * @parm xc_handle a handle to an open hypervisor interface
+ * @parm domid the domain to query
+ * @parm min_width the smallest address width to query (0 if don't care)
+ * @parm max_width the largest address width to query (0 if don't care)
+ * @parm node the node to query (-1 for all)
+ * @parm *bytes caller variable to put total bytes counted
+ * @return 0 on success, <0 on failure.
+ */
+int xc_availheap(int xc_handle, int min_width, int max_width, int node,
+                 uint64_t *bytes);
 
 /*
  * Trace Buffer Operations