xen: use host E820 map for dom0

When running as initial domain, get the real physical memory map from
xen using the XENMEM_machine_memory_map hypercall and use it to setup
the e820 regions.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 7 insertions, 2 deletions

diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 7a4ab05cff8a..0ce9d58cb29d 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -149,6 +149,7 @@ char * __init xen_memory_setup(void)
         unsigned long extra_pages = 0;
         unsigned long extra_limit;
         int i;
+        int op;
 
         max_pfn = min(MAX_DOMAIN_PAGES, max_pfn);
         mem_end = PFN_PHYS(max_pfn);
@@ -156,7 +157,10 @@ char * __init xen_memory_setup(void)
         memmap.nr_entries = E820MAX;
         set_xen_guest_handle(memmap.buffer, map);
 
-        rc = HYPERVISOR_memory_op(XENMEM_memory_map, &memmap);
+        op = xen_initial_domain() ?
+                XENMEM_machine_memory_map :
+                XENMEM_memory_map;
+        rc = HYPERVISOR_memory_op(op, &memmap);
         if (rc == -ENOSYS) {
                 memmap.nr_entries = 1;
                 map[0].addr = 0ULL;
@@ -235,7 +239,8 @@ char * __init xen_memory_setup(void)
         else
                 extra_pages = 0;
 
-        xen_add_extra_mem(extra_pages);
+        if (!xen_initial_domain())
+                xen_add_extra_mem(extra_pages);
 
         return "Xen";
 }