tools: Synchronize privcmd header constants

Since Linux's git commit ceb90fa0a8008059ecbbf9114cb89dc71a730bb6,
the privcmd.h interface between Linux and libxc specifies two new
constants, PRIVCMD_MMAPBATCH_MFN_ERROR and
PRIVCMD_MMAPBATCH_PAGED_ERROR. These constants represent the error
codes encoded in the top nibble of an mfn slot passed to the legacy
MMAPBATCH ioctl.

In particular, libxenctrl checks for the equivalent of the latter
constant when dealing with paged out frames that might be the target
of a foreign map.

Previously, the relevant constant was defined in the domctl hypervisor
interface header (XEN_DOMCTL_PFINFO_PAGEDTAB). Because this
top-nibble encoding is a contract between the dom0 kernel and libxc,
a domctl.h definition is misplaced.

- Sync the privcmd.h header to that now available in upstream Linux
- Update libxc appropriately
- Remove the unnecessary constant in domctl.h

Signed-off-by: Andres Lagar-Cavilla <andres@lagarcavilla.org>
Acked-by: Ian Campbell <ian.campbelL@citrix.com>
Committed-by: Ian Campbell <ian.campbell@citrix.com>

3 files changed, 8 insertions, 6 deletions

diff --git a/tools/include/xen-sys/Linux/privcmd.h b/tools/include/xen-sys/Linux/privcmd.h
index d35aac9baa..5be860af39 100644
--- a/tools/include/xen-sys/Linux/privcmd.h
+++ b/tools/include/xen-sys/Linux/privcmd.h
@@ -64,6 +64,9 @@ typedef struct privcmd_mmapbatch {
 	xen_pfn_t __user *arr; /* array of mfns - top nibble set on err */
 } privcmd_mmapbatch_t; 
 
+#define PRIVCMD_MMAPBATCH_MFN_ERROR     0xf0000000U
+#define PRIVCMD_MMAPBATCH_PAGED_ERROR   0x80000000U
+
 typedef struct privcmd_mmapbatch_v2 {
 	unsigned int num; /* number of pages to populate */
 	domid_t dom;      /* target domain */
diff --git a/tools/libxc/xc_linux_osdep.c b/tools/libxc/xc_linux_osdep.c
index 787e74285e..ca545d8228 100644
--- a/tools/libxc/xc_linux_osdep.c
+++ b/tools/libxc/xc_linux_osdep.c
@@ -129,7 +129,7 @@ static int xc_map_foreign_batch_single(int fd, uint32_t dom,
 
     do
     {
-        *mfn ^= XEN_DOMCTL_PFINFO_PAGEDTAB;
+        *mfn ^= PRIVCMD_MMAPBATCH_PAGED_ERROR;
         usleep(100);
         rc = ioctl(fd, IOCTL_PRIVCMD_MMAPBATCH, &ioctlx);
     }
@@ -166,8 +166,8 @@ static void *linux_privcmd_map_foreign_batch(xc_interface *xch, xc_osdep_handle
 
         for ( i = 0; i < num; i++ )
         {
-            if ( (arr[i] & XEN_DOMCTL_PFINFO_LTAB_MASK) ==
-                 XEN_DOMCTL_PFINFO_PAGEDTAB )
+            if ( (arr[i] & PRIVCMD_MMAPBATCH_MFN_ERROR) ==
+                           PRIVCMD_MMAPBATCH_PAGED_ERROR )
             {
                 unsigned long paged_addr = (unsigned long)addr + (i << XC_PAGE_SHIFT);
                 rc = xc_map_foreign_batch_single(fd, dom, &arr[i],
@@ -323,12 +323,12 @@ static void *linux_privcmd_map_foreign_bulk(xc_interface *xch, xc_osdep_handle h
             default:
                 err[i] = -EINVAL;
                 continue;
-            case XEN_DOMCTL_PFINFO_PAGEDTAB:
+            case PRIVCMD_MMAPBATCH_PAGED_ERROR:
                 if ( rc != -ENOENT )
                 {
                     err[i] = rc ?: -EINVAL;
                     continue;
-                 }
+                }
                 rc = xc_map_foreign_batch_single(fd, dom, pfn + i,
                         (unsigned long)addr + ((unsigned long)i<<XC_PAGE_SHIFT));
                 if ( rc < 0 )
diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
index f2409ec76c..7c0f23df2e 100644
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -136,7 +136,6 @@ DEFINE_XEN_GUEST_HANDLE(xen_domctl_getmemlist_t);
 #define XEN_DOMCTL_PFINFO_LPINTAB (0x1U<<31)
 #define XEN_DOMCTL_PFINFO_XTAB    (0xfU<<28) /* invalid page */
 #define XEN_DOMCTL_PFINFO_XALLOC  (0xeU<<28) /* allocate-only page */
-#define XEN_DOMCTL_PFINFO_PAGEDTAB (0x8U<<28)
 #define XEN_DOMCTL_PFINFO_LTAB_MASK (0xfU<<28)
 
 struct xen_domctl_getpageframeinfo {