[Xen-devel] [PATCH 09/22] vixen: modify the e820 table to advertise HVM special pages as RAM

[Anthony Liguori <aliguori@xxxxxxxx>]

From: Anthony Liguori <aliguori@xxxxxxxxxx>

In order to be able to assign the Xenstore page into the Vixen guest,
we need struct page_info's to exist.  We do this by modifying the
e820 table early in boot and then using the badpages handling to
prevent these pages from being added to the xenheap.

Since these pages exist in a somewhat weird state in Xen, we need
to relax permission checking too in order to be able to assign them
to the guest.

Signed-off-by: Anthony Liguori <aliguori@xxxxxxxxxx>
---
 xen/arch/x86/e820.c |  6 ++++++
 xen/arch/x86/mm.c   | 21 ++++++++++++++++++++-
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/e820.c b/xen/arch/x86/e820.c
index 7c572ba..9ee147f 100644
--- a/xen/arch/x86/e820.c
+++ b/xen/arch/x86/e820.c
@@ -9,6 +9,7 @@
 #include <asm/processor.h>
 #include <asm/mtrr.h>
 #include <asm/msr.h>
+#include <asm/guest/vixen.h>
 
 /*
  * opt_mem: Limit maximum address of physical RAM.
@@ -698,6 +699,11 @@ unsigned long __init init_e820(const char *str, struct 
e820map *raw)
         print_e820_memory_map(raw->map, raw->nr_map);
     }
 
+    if ( is_vixen() )
+    {
+        /* Pretend that passed through special pages are RAM */
+        e820_change_range_type(raw, 0xfeffc000, 0xff000000, E820_RESERVED, 
E820_RAM);
+    }
     machine_specific_memory_setup(raw);
 
     printk("%s RAM map:\n", str);
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index a56f875..935901b 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -122,6 +122,7 @@
 #include <asm/fixmap.h>
 #include <asm/io_apic.h>
 #include <asm/pci.h>
+#include <asm/guest.h>
 
 #include <asm/hvm/grant_table.h>
 #include <asm/pv/grant_table.h>
@@ -945,7 +946,7 @@ get_page_from_l1e(
             case 0:
                 break;
             case 1:
-                if ( !is_hardware_domain(l1e_owner) )
+                if ( !is_vixen() && !is_hardware_domain(l1e_owner) )
                     break;
                 /* fallthrough */
             case -1:
@@ -5536,6 +5537,21 @@ void arch_dump_shared_mem_info(void)
             mem_sharing_get_nr_saved_mfns());
 }
 
+const unsigned long *__init
+vixen_get_platform_badpages(unsigned int *array_size)
+{
+    static unsigned long __initdata bad_pages[] = {
+        0xfeffc000,
+        0xfeffd000,
+        0xfeffe000,
+        0xfefff000,
+    };
+
+    *array_size = ARRAY_SIZE(bad_pages);
+
+    return bad_pages;
+}
+
 const unsigned long *__init get_platform_badpages(unsigned int *array_size)
 {
     u32 igd_id;
@@ -5547,6 +5563,9 @@ const unsigned long *__init 
get_platform_badpages(unsigned int *array_size)
         0x40004000,
     };
 
+    if ( is_vixen() )
+        return vixen_get_platform_badpages(array_size);
+
     *array_size = ARRAY_SIZE(bad_pages);
     igd_id = pci_conf_read32(0, 0, 2, 0, 0);
     if ( !IS_SNB_GFX(igd_id) )
-- 
1.9.1


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