tree 7e355ce31516dbd959a49639e6f2ed15f6cb6e6f
parent fc02086b5ab8de50ce8234cf8f42b254de9e5d91
author Paolo Bonzini <pbonzini@redhat.com> 1412606997 +0200
committer Paolo Bonzini <pbonzini@redhat.com> 1412861775 +0200

linuxboot: compute initrd loading address

Even though hw/i386/pc.c tries to compute a valid loading address for the
initrd, close to the top of RAM, this does not take into account other
data that is malloced into that memory by SeaBIOS.

Luckily we can easily look at the memory map to find out how much memory is
used up there.  This patch places the initrd in the first four gigabytes,
below the first hole (as returned by INT 15h, AX=e801h).

Without this patch:
[    0.000000] init_memory_mapping: [mem 0x07000000-0x07fdffff]
[    0.000000] RAMDISK: [mem 0x0710a000-0x07fd7fff]

With this patch:
[    0.000000] init_memory_mapping: [mem 0x07000000-0x07fdffff]
[    0.000000] RAMDISK: [mem 0x07112000-0x07fdffff]

So linuxboot is able to use the 64k that were added as padding for
QEMU <= 2.1.

Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>