On 02/01/13 16:46, Ben Guthro wrote:

On Wed, Jan 2, 2013 at 10:31 AM, Ben Guthro <ben@guthro.net> wrote:

The actual wakeup vector is wakeup_start in xen/arch/x86/boot/wakeup.S

I'll take a look at this, thanks for the pointer.

I've tried putting a "ud2" instruction at the start of wakeup_start - and the machine doesn't seem to crash.

I also tried a divide by zero in the same place, just for good measure.

It would appear that this wakeup_start is not getting executed on resume.

Presumably, the BIOS is causing the disk, and CDROM LEDs to flash, while enumerating the bus.

A difference between Xen 4.0.y and 4.2.y seems to be the removal of the boot trampoline fixed address, that much of this is calculated as an offset of.

Could an error in this path cause such a behavior?

It seems the trampoline is allocated at a different location in Xen 4.2 (EBDA - 64k instead of 0x7c000). I have attached a quick patch to move the location back to 0x7c000 to see if that helps your system. I have compile and boot tested the patch but not had time to do a S3 test on it. Can you try it on your system?

Can you also run the following command as root in dom0:

hexdump -s 0x400 -n 32 /dev/mem

/btg

Malcolm