[v6][PATCH 4/7] libxc/hvm_info_table: introduce a new field nr_reserved_device_memory_map

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

In hvm_info_table this field represents the number of all reserved device
memory maps. It will be convenient to expose such a information to VM.
While building hvm info, libxc is responsible for constructing this number
after check_rdm_overlap().

Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>

diff --git a/tools/libxc/xc_hvm_build_x86.c b/tools/libxc/xc_hvm_build_x86.c
index 299e33a..8c61422 100644
--- a/tools/libxc/xc_hvm_build_x86.c
+++ b/tools/libxc/xc_hvm_build_x86.c
@@ -89,7 +89,8 @@ static int modules_init(struct xc_hvm_build_args *args,
 }
 
 static void build_hvm_info(void *hvm_info_page, uint64_t mem_size,
-                           uint64_t mmio_start, uint64_t mmio_size)
+                           uint64_t mmio_start, uint64_t mmio_size,
+                           unsigned int num)
 {
     struct hvm_info_table *hvm_info = (struct hvm_info_table *)
         (((unsigned char *)hvm_info_page) + HVM_INFO_OFFSET);
@@ -119,6 +120,9 @@ static void build_hvm_info(void *hvm_info_page, uint64_t mem_size,
     hvm_info->high_mem_pgend = highmem_end >> PAGE_SHIFT;
     hvm_info->reserved_mem_pgstart = ioreq_server_pfn(0);
 
+    /* Reserved device memory map number. */
+    hvm_info->nr_reserved_device_memory_map = num;
+
     /* Finish with the checksum. */
     for ( i = 0, sum = 0; i < hvm_info->length; i++ )
         sum += ((uint8_t *)hvm_info)[i];
@@ -329,6 +333,7 @@ static int setup_guest(xc_interface *xch,
     int claim_enabled = args->claim_enabled;
     xen_pfn_t special_array[NR_SPECIAL_PAGES];
     xen_pfn_t ioreq_server_array[NR_IOREQ_SERVER_PAGES];
+    unsigned int num_reserved = 0;
 
     if ( nr_pages > target_pages )
         pod_mode = XENMEMF_populate_on_demand;
@@ -371,6 +376,8 @@ static int setup_guest(xc_interface *xch,
     if ( rc < 0 )
         goto error_out;
 
+    num_reserved = rc;
+
     for ( i = 0; i < nr_pages; i++ )
         page_array[i] = i;
     for ( i = mmio_start >> PAGE_SHIFT; i < nr_pages; i++ )
@@ -540,7 +547,7 @@ static int setup_guest(xc_interface *xch,
               xch, dom, PAGE_SIZE, PROT_READ | PROT_WRITE,
               HVM_INFO_PFN)) == NULL )
         goto error_out;
-    build_hvm_info(hvm_info_page, v_end, mmio_start, mmio_size);
+    build_hvm_info(hvm_info_page, v_end, mmio_start, mmio_size, num_reserved);
     munmap(hvm_info_page, PAGE_SIZE);
 
     /* Allocate and clear special pages. */
diff --git a/xen/include/public/hvm/hvm_info_table.h b/xen/include/public/hvm/hvm_info_table.h
index 36085fa..bf401d5 100644
--- a/xen/include/public/hvm/hvm_info_table.h
+++ b/xen/include/public/hvm/hvm_info_table.h
@@ -65,6 +65,9 @@ struct hvm_info_table {
      */
     uint32_t    high_mem_pgend;
 
+    /* How many reserved device memory maps does we have? */
+    uint32_t    nr_reserved_device_memory_map;
+
     /* Bitmap of which CPUs are online at boot time. */
     uint8_t     vcpu_online[(HVM_MAX_VCPUS + 7)/8];
 };
-- 
1.9.1