Re: [Qemu-devel] [PATCH v2 3/6] hw/mips_int: hold BQL for all interrupt requests

[Alex Bennée]

Paolo Bonzini <address@hidden> writes:

> On 04/04/2018 12:23, Alex Bennée wrote:
>>
>>> From: Aleksandar Markovic <address@hidden>
>>>
>>> Make sure BQL is held for all interrupt requests.
>>>
>>> For MTTCG-enabled configurations, handling soft and hard interrupts
>>> between vCPUs must be properly locked. By acquiring BQL, make sure
>>> all paths triggering an IRQ are synchronized.
>>>
>>> Signed-off-by: Miodrag Dinic <address@hidden>
>>> Signed-off-by: Aleksandar Markovic <address@hidden>
>
> Is this actually necessary?  What paths are not taking the lock?

Helpers functions have to manually take the lock. AIUI from this patch
the if (locked) dance allows a single function to be used which may
trigger an IRQ from both helpers (no automatic locking) and hw emulation
(locked by default).

>
> Thanks,
>
> Paolo


--
Alex Bennée