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.
Signed-off-by: Dave Young <dyoung@redhat.com>
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com>
Reviewed-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 file changed