xc: use XENMEM_claim_pages hypercall during guest creation.

We add an extra parameter to the structures passed to the
PV routine (arch_setup_meminit) and HVM routine (setup_guest)
that determines whether the claim hypercall is to be done.

The contents of the 'claim_enabled' is defined as an 'int'
in case the hypercall expands in the future with extra
flags (for example for per-NUMA allocation). For right now
the proper values are: 0 to disable it or 1 to enable
it.

If the hypervisor does not support this function, the
xc_domain_claim_pages and xc_domain_get_outstanding_pages
will silently return 0 (and set errno to zero).

Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
[v2: Updated per Ian's recommendations]
[v3: Added support for out-of-sync hypervisor]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>

1 files changed, 30 insertions, 0 deletions

diff --git a/tools/libxc/xc_domain.c b/tools/libxc/xc_domain.c
index 480ce91500..299c9073b7 100644
--- a/tools/libxc/xc_domain.c
+++ b/tools/libxc/xc_domain.c
@@ -775,6 +775,36 @@ int xc_domain_add_to_physmap(xc_interface *xch,
     return do_memory_op(xch, XENMEM_add_to_physmap, &xatp, sizeof(xatp));
 }
 
+int xc_domain_claim_pages(xc_interface *xch,
+                               uint32_t domid,
+                               unsigned long nr_pages)
+{
+    int err;
+    struct xen_memory_reservation reservation = {
+        .nr_extents   = nr_pages,
+        .extent_order = 0,
+        .mem_flags    = 0, /* no flags */
+        .domid        = domid
+    };
+
+    set_xen_guest_handle(reservation.extent_start, HYPERCALL_BUFFER_NULL);
+
+    err = do_memory_op(xch, XENMEM_claim_pages, &reservation, sizeof(reservation));
+    /* Ignore it if the hypervisor does not support the call. */
+    if (err == -1 && errno == ENOSYS)
+        err = errno = 0;
+    return err;
+}
+unsigned long xc_domain_get_outstanding_pages(xc_interface *xch)
+{
+    long ret = do_memory_op(xch, XENMEM_get_outstanding_pages, NULL, 0);
+
+    /* Ignore it if the hypervisor does not support the call. */
+    if (ret == -1 && errno == ENOSYS)
+        ret = errno = 0;
+    return ret;
+}
+
 int xc_domain_populate_physmap(xc_interface *xch,
                                uint32_t domid,
                                unsigned long nr_extents,