[Xen-devel] [PATCH 3/4] x86/e820: assume memmap provided when booted as a Xen guest is correct

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

This implies there's no need to forcefully reserve the VGA MMIO
region, since the memory map provided will be correct.

Reported-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxx>
---
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Cc: Wei Liu <wei.liu2@xxxxxxxxxx>
---
 xen/arch/x86/e820.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/e820.c b/xen/arch/x86/e820.c
index 7c5b85118f..5e46d4ec53 100644
--- a/xen/arch/x86/e820.c
+++ b/xen/arch/x86/e820.c
@@ -537,11 +537,12 @@ static void __init machine_specific_memory_setup(struct 
e820map *raw)
 
     reserve_dmi_region();
 
-    /*
-     * Some BIOSes claim RAM in the 640k - 1M region.
-     * Not right. Fix it up.
-     */
-    reserve_vga_region();
+    if ( !xen_guest )
+        /*
+         * Some BIOSes claim RAM in the 640k - 1M region.
+         * Not right. Fix it up.
+         */
+        reserve_vga_region();
 
     top_of_ram = mtrr_top_of_ram();
     if ( top_of_ram )
-- 
2.17.2 (Apple Git-113)


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