commit 8a369e20e701c9d220834e0daa027e65acd35214
author Anthony PERARD <anthony.perard@citrix.com> Wed Jul 20 08:17:43 2011 +0000
committer Alexander Graf <agraf@suse.de> Tue Jul 26 06:57:55 2011 +0200
tree b9e1f2887288ec0a1b11b9736a4ac9f23dc60ad2
parent f15fbc4bd1a24bd1477a846e63e62c6d435912f8

xen: Fix the memory registration to reflect of what is done by Xen.

A Xen guest memory is allocated by libxc. But this memory is not
allocated continuously, instead, it leaves the VGA IO memory space not
allocated, same for the MMIO space (at HVM_BELOW_4G_MMIO_START of size
HVM_BELOW_4G_MMIO_LENGTH).

So to reflect that, we do not register the physical memory for this two
holes. But we still keep only one RAMBlock for the all RAM as it is more
easier than have two separate blocks (1 above 4G). Also this prevent QEMU
from use the MMIO space for a ROM.

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

xen-all.c

diff --git a/xen-all.c b/xen-all.c
index 53296bf..9eaeac1 100644
--- a/xen-all.c
+++ b/xen-all.c
@@ -19,6 +19,7 @@
 
 #include <xen/hvm/ioreq.h>
 #include <xen/hvm/params.h>
+#include <xen/hvm/e820.h>
 
 //#define DEBUG_XEN
 
@@ -144,6 +145,12 @@
     new_block->host = NULL;
     new_block->offset = 0;
     new_block->length = ram_size;
+    if (ram_size >= HVM_BELOW_4G_RAM_END) {
+        /* Xen does not allocate the memory continuously, and keep a hole at
+         * HVM_BELOW_4G_MMIO_START of HVM_BELOW_4G_MMIO_LENGTH
+         */
+        new_block->length += HVM_BELOW_4G_MMIO_LENGTH;
+    }
 
     QLIST_INSERT_HEAD(&ram_list.blocks, new_block, next);
 
@@ -152,20 +159,26 @@
     memset(ram_list.phys_dirty + (new_block->offset >> TARGET_PAGE_BITS),
            0xff, new_block->length >> TARGET_PAGE_BITS);
 
-    if (ram_size >= 0xe0000000 ) {
-        above_4g_mem_size = ram_size - 0xe0000000;
-        below_4g_mem_size = 0xe0000000;
+    if (ram_size >= HVM_BELOW_4G_RAM_END) {
+        above_4g_mem_size = ram_size - HVM_BELOW_4G_RAM_END;
+        below_4g_mem_size = HVM_BELOW_4G_RAM_END;
     } else {
         below_4g_mem_size = ram_size;
     }
 
-    cpu_register_physical_memory(0, below_4g_mem_size, new_block->offset);
-#if TARGET_PHYS_ADDR_BITS > 32
+    cpu_register_physical_memory(0, 0xa0000, 0);
+    /* Skip of the VGA IO memory space, it will be registered later by the VGA
+     * emulated device.
+     *
+     * The area between 0xc0000 and 0x100000 will be used by SeaBIOS to load
+     * the Options ROM, so it is registered here as RAM.
+     */
+    cpu_register_physical_memory(0xc0000, below_4g_mem_size - 0xc0000,
+                                 0xc0000);
     if (above_4g_mem_size > 0) {
         cpu_register_physical_memory(0x100000000ULL, above_4g_mem_size,
-                                     new_block->offset + below_4g_mem_size);
+                                     0x100000000ULL);
     }
-#endif
 }
 
 void xen_ram_alloc(ram_addr_t ram_addr, ram_addr_t size)