Re: [Qemu-devel] qemu-2.9 crashes in tcg_handle_interrupt() during winx64 boot

[Paolo Bonzini <pbonzini@redhat.com>]

On 31/03/2017 10:58, Alex Bennée wrote:
> 
> Igor Mammedov <imammedo@redhat.com> writes:
> 
>> On Thu, 30 Mar 2017 16:05:58 +0100
>> Alex Bennée <alex.bennee@linaro.org> wrote:
>>
>>> Igor Mammedov <imammedo@redhat.com> writes:
>>>
>>>> (PS: resend due to wrong qemu-devel mail list address in original
>>>> email)
>>>
>>> Le *sigh* another way of x86 generating IRQs ;-)
>>>
>>> Could you test this please?
>>>
>>> target/i386/misc_helper: wrap BQL around another IRQ generator
>>>
>>> Anything that calls into HW emulation must be protected by the BQL.
>>>
>>> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
>> it doesn't help,
>> it asserts in the same place anyway
> 
> That's weird. If the lock was already held I could see it failing higher
> up but this seems to imply we are dropping a lock as we descend into
> hardware emulation.

Seems weird to me too.

> How often does this leg of the helper get called?

Continuously under Windows, never on Linux.  But you can also try
kvm-unit-tests probably to trigger it:

$ qemu-system-x86_64 \
   -kernel x86/vmexit.flat -serial stdio \
   --append 'cpuid mov_to_cr8' -device isa-debug-exit,iobase=0xf4


Thanks,

paolo