Hi all,
We've been seeing a problem lately running FreeBSD 9.1 and 9.2 (latest stable) which causes the guest to crash during boot when QEMU is run on an AMD processor with the 'xsave' flag set.
To reproduce this behaviour:
- Boot a FreeBSD 9.1 or 9.2 guest or even installation CD on an AMD processor with xsave enabled. Use '-cpu host'.
- After the bootloader, the guest will crash almost immediately with the message 'kernel trap 12 with interrupts disabled'. This occurs before any disks are loaded, so it's not possible to get a memory dump from the guest OS for backtrace.
- Boot again with '-cpu host,-xsave'. The guest should boot successfully.
This was seen on AMD Opteron 6238 processor family, and does not affect our Opteron 6128s (due to lack of the xsave flag).
We've also tested on an Intel Xeon E5-2640 processor which has the xsave flag set and verified that we do not see this behaviour.
Based on this, I believe that the xsave instruction is not being correctly emulated on some hardware. Is this a known issue?
Thanks in advance for looking, and please let me know if we can provide any more useful information to help diagnose/fix this.
Best regards,
Owen Tuz