[RFC][v3][PATCH 4/6] xen:x86: add XENMEM_reserved_device_memory_map to expose RMRR

[Tiejun Chen <tiejun.chen@intel.com>]

We should expose RMRR mapping to libxc, then setup_guest() can
check if current MMIO is not covered by any RMRR mapping.

Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
---
 xen/arch/x86/mm.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index d23cb3f..fb6e92f 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -4769,6 +4769,38 @@ long arch_memory_op(unsigned long cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
         return 0;
     }
 
+    case XENMEM_reserved_device_memory_map:
+    {
+        struct xen_memory_map map;
+        XEN_GUEST_HANDLE(e820entry_t) buffer;
+        XEN_GUEST_HANDLE_PARAM(e820entry_t) buffer_param;
+        unsigned int i;
+
+        if ( copy_from_guest(&map, arg, 1) )
+            return -EFAULT;
+        if ( map.nr_entries < rmrr_maps.nr_map + 1 )
+            return -EINVAL;
+
+        buffer_param = guest_handle_cast(map.buffer, e820entry_t);
+        buffer = guest_handle_from_param(buffer_param, e820entry_t);
+        if ( !guest_handle_okay(buffer, map.nr_entries) )
+            return -EFAULT;
+
+        /* Currently we just need to cover RMRR. */
+        for ( i = 0; i < rmrr_maps.nr_map; ++i )
+        {
+            if ( __copy_to_guest_offset(buffer, i, rmrr_maps.map + i, 1) )
+                return -EFAULT;
+        }
+
+        map.nr_entries = rmrr_maps.nr_map;
+
+        if ( __copy_to_guest(arg, &map, 1) )
+            return -EFAULT;
+
+        return 0;
+    }
+
     case XENMEM_machphys_mapping:
     {
         struct xen_machphys_mapping mapping = {
-- 
1.9.1