kdump x86: fix total mem size calculation for reservation

crashkernel reservation need know the total memory size. Current get_total_mem simply use max_pfn - min_low_pfn. It is wrong because it will including memory holes in the middle.

Especially for kvm guest with memory > 0xe0000000, there's below in qemu code:
qemu split memory as below:

    if (ram_size >= 0xe0000000 ) {
        above_4g_mem_size = ram_size - 0xe0000000;
        below_4g_mem_size = 0xe0000000;
    } else {
        below_4g_mem_size = ram_size;
    }

So for 4G mem guest, seabios will insert a 512M usable region beyond of 4G. Thus in above case max_pfn - min_low_pfn will be more than original memsize.

Fixing this issue by using memblock_phys_mem_size() to get the total memsize.

[v1 -> v2]: refresh the patch based on latest linus tree

Signed-off-by Dave Young <[email protected]>

Reviewed-by WANG Cong <[email protected]>

---
 arch/x86/kernel/setup.c |   11 +----------
 1 file changed, 1 insertion(+), 10 deletions(-)

arch/x86/kernel/setup.c +1 -11

@@ -509,15 +509,6 @@ static void __init memblock_x86_reserve_
 
 #ifdef CONFIG_KEXEC
 
-static inline unsigned long long get_total_mem(void)
-{
-	unsigned long long total;
-
-	total = max_pfn - min_low_pfn;
-
-	return total << PAGE_SHIFT;
-}
-
 /*
  * Keep the crash kernel below this limit.  On 32 bits earlier kernels
  * would limit the kernel to the low 512 MiB due to mapping restrictions.

@@ -536,7 +527,7 @@ static void __init reserve_crashkernel(v
 	unsigned long long crash_size, crash_base;
 	int ret;
 
-	total_mem = get_total_mem();
+	total_mem = memblock_phys_mem_size();
 
 	ret = parse_crashkernel(boot_command_line, total_mem,
 			&crash_size, &crash_base);
--

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

_______________________________________________
kexec mailing list
[email protected]
http://lists.infradead.org/mailman/listinfo/kexec