Re: [Qemu-devel] [Bug 1706296] Re: Booting NT 4 disk causes /home/rjones/d/qemu/cpus.c:1580:qemu_mutex_lock_iothread: assertion failed: (!qemu_mutex_iothread_locked())

["Alex Bennée" <alex.bennee@linaro.org>]

John Arbuckle <programmingkidx@gmail.com> writes:

> Using '-cpu 486' gets past the assertion error. I guess Windows NT 4.0
> is not compatible with newer Intel processors.

It might be related. The assertion error is caused by the fact an
exception has occurred and processor is trying to dump a stack frame that
overlaps from RAM into device memory. As the IRQ/exception handling is
already under the BQL (as it changes machine state) we get the assertion
when it tries to take the BQL a second time when accessing device
memory.

We can drop the lock in the stack frame writing code but I don't know
what effect that would have as the guest still might crash having tried
to write a stack frame to device memory....

>
> Currently I can install Windows NT 4.0, but booting from the
> installation has its problems. It won't boot unless you use the NTFS
> file system. Even with this file system I still see a BSOD that states
> INACCESSIBLE_BOOT_DEVICE. Not sure what is wrong. Switching to a SCSI
> controller didn't help.


--
Alex Bennée