libxl: put RSDP for PVH guest near 4GB

Instead of locating the RSDP table below 1MB put it just below 4GB
like the rest of the ACPI tables in case of PVH guests. This will
avoid punching more holes than necessary into the memory map.

Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>

tools/libxc/xc_dom_hvmloader.c

@@ -136,7 +136,7 @@ static int module_init_one(struct xc_dom_image *dom,
     struct xc_dom_seg seg;
     void *dest;
 
-    if ( module->length )
+    if ( module->length && !module->guest_addr_out )
     {
         if ( xc_dom_alloc_segment(dom, &seg, name, 0, module->length) )
             goto err;

tools/libxl/libxl_x86_acpi.c

@@ -22,8 +22,6 @@
 
  /* Number of pages holding ACPI tables */
 #define NUM_ACPI_PAGES 16
-/* Store RSDP in the last 64 bytes of BIOS RO memory */
-#define RSDP_ADDRESS (0x100000 - 64)
 #define ACPI_INFO_PHYSICAL_ADDRESS 0xfc000000
 
 struct libxl_acpi_ctxt {
@@ -220,7 +218,8 @@ int libxl__dom_load_acpi(libxl__gc *gc,
 
     dom->acpi_modules[0].data = (void *)config.rsdp;
     dom->acpi_modules[0].length = 64;
-    dom->acpi_modules[0].guest_addr_out = RSDP_ADDRESS;
+    dom->acpi_modules[0].guest_addr_out = ACPI_INFO_PHYSICAL_ADDRESS +
+        (1 + acpi_pages_num) * libxl_ctxt.page_size;
 
     dom->acpi_modules[1].data = (void *)config.infop;
     dom->acpi_modules[1].length = 4096;