Re: [RFC] use realmode code to reserve end-of-conventional-memoryto 1MB
From: H. Peter Anvin
Date: Wed Mar 05 2008 - 11:13:00 EST
Eduardo Habkost wrote:
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 3bad477..2341492 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -38,7 +38,8 @@ char * __init xen_memory_setup(void)
unsigned long max_pfn = xen_start_info->nr_pages;
e820.nr_map = 0;
- add_memory_region(0, PFN_PHYS(max_pfn), E820_RAM);
+ add_memory_region(0, LOWMEMSIZE(), E820_RAM);
+ add_memory_region(HIGH_MEMORY, PFN_PHYS(max_pfn)-HIGH_MEMORY, E820_RAM);
Won't this waste 300+ KB of Perfectly Good RAM? Or I understood it
incorrectly?
I am aware that it would take more work to tell all kernel code that it
shouldn't look for BIOS data on this region when running as a domU guest,
but it seems that it would be a better solution.
No, the right thing is for Xen to not try to map RAM in this area.
-hpa
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