Re: [PATCH] OvmfPkg: End timer interrupt later to avoid stack overflow under load

["Laszlo Ersek" <lersek@redhat.com>]

On 06/17/20 19:23, Igor Druzhinin wrote:
> On 17/06/2020 17:59, Paolo Bonzini wrote:
>> [CAUTION - EXTERNAL EMAIL] DO NOT reply, click links, or open attachments unless you have verified the sender and know the content is safe.
>>
>> On 17/06/20 17:46, Laszlo Ersek wrote:
>>>> That said, Igor's patch seems correct to me.  In fact, I'd even move
>>>> DisableInterrupts before gBS->RestoreTPL unless there's a good reason
>>>> not to do so.
>>> OK, thank you!
>>>
>>> Igor, please confirm if you'd like to submit v2 with the update
>>> suggested by Paolo, or if you prefer the current version. We're at the
>>> beginning of the current development cycle, so I guess we can apply the
>>> patch and see how it works in practice. If it ends up wreaking havoc on
>>> some platforms, we can always revert the patch in time for the next
>>> stable tag (edk2-stable202008).
>>
>> For what it's worth "correct" means that I don't see anything that could
>> break and in fact I find it good policy hygienic not to allow recursive
>> interrupts.
>>
>> v1 is okay for me too, so:
>>
>> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>

Thank you, Paolo!

> Thanks, unfortunately it's not possible to move DisableInterrupts inside
> TPL block as RestoreTPL would immediately enable them according to current
> logic.
> 
> IMO RaiseTPL could technically save interrupt state inside it (in that
> case it was disabled) and then honor it in RestoreTPL but that might have
> more surprise consequences than the proposed change I reckon.
> 
> I will create a BZ ticket as requested.

Thanks -- please follow up with the URL, and then I'll pick up your
current patch, with Paolo's R-b and the BZ URL added to the commit message.

Acked-by: Laszlo Ersek <lersek@redhat.com>

Thanks
Laszlo