On 12/19/2016 06:32 PM, Borislav Petkov wrote:
On Mon, Dec 19, 2016 at 07:43:40PM +0100, Borislav Petkov wrote:
On Mon, Dec 19, 2016 at 01:12:25PM -0500, Boris Ostrovsky wrote:
IIUIC find_microcode_in_initrd() is called with paging on only on Intel
(which is where I observed it).
Ah, that was an important fact. Yes, I can repro it now.
Ok, questions:
* does your guest relocate the ramdisk?
This is not a guest. I crashed with baremetal kernel.
I.e., do you see something like this in dmesg before the splat:
[ 0.000000] RAMDISK: [mem 0x7f84c000-0x7ffcffff]
[ 0.000000] Allocated new RAMDISK: [mem 0x3647a000-0x36bfd9e6]
[ 0.000000] Move RAMDISK from [mem 0x7f84c000-0x7ffcf9e6] to [mem
0x3647a000-0x36bfd9e6]
^^^^^^^^^^^^^^
If not, then I know what happens.
Also, does it work if you change these lines:
if (!use_pa && relocated_ramdisk)
start = initrd_start;
to:
if (!use_pa)
start = initrd_start;
Yes, it does.
I also thought it might be better but I haven't gone through the code to
make sure this would always work.
I can run more tests tomorrow if you want.
-boris
Because if that works, I can actually simplify that function radically.
But more tomorrow.
Thanks.
