libxc: introduce xc_domain_get_guest_width()

As a wrapper to XEN_DOMCTL_get_address_size, and use it
wherever the call was being issued directly via do_domctl(),
saving quite some line of code.

Actually, the function returns the guest width in bytes,
rather than directly what XEN_DOMCTL_get_address_size provides
(which is a number of bits), since that is what it is useful
almost everywhere.

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

1 files changed, 3 insertions, 10 deletions

diff --git a/tools/libxc/xc_dom_x86.c b/tools/libxc/xc_dom_x86.c
index 41f59d3dd1..7cc2ff2411 100644
--- a/tools/libxc/xc_dom_x86.c
+++ b/tools/libxc/xc_dom_x86.c
@@ -54,24 +54,17 @@ const char *xc_domain_get_native_protocol(xc_interface *xch,
     int ret;
     uint32_t guest_width;
     const char *protocol;
-    DECLARE_DOMCTL;
 
-    memset(&domctl, 0, sizeof(domctl));
-    domctl.domain = domid;
-    domctl.cmd = XEN_DOMCTL_get_address_size;
-
-    ret = do_domctl(xch, &domctl);
+    ret = xc_domain_get_guest_width(xch, domid, &guest_width);
 
     if ( ret )
         return NULL;
 
-    guest_width = domctl.u.address_size.size;
-
     switch (guest_width) {
-    case 32: /* 32 bit guest */
+    case 4: /* 32 bit guest */
         protocol = XEN_IO_PROTO_ABI_X86_32;
         break;
-    case 64: /* 64 bit guest */
+    case 8: /* 64 bit guest */
         protocol = XEN_IO_PROTO_ABI_X86_64;
         break;
     default: