Re: [PATCH] ArmPkg/Gic: force GIC driver to run before CPU arch protocol driver

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

On 6 February 2018 at 14:55, Marc Zyngier <marc.zyngier@arm.com> wrote:
> On 06/02/18 12:04, Ard Biesheuvel wrote:
>> Currently, the GIC driver has a static dependency on the CPU arch protocol
>> driver, so it can register its IRQ handler at init time. This means there
>> is a window between dispatch of the CPU driver and dispatch of the GIC
>> driver where any unexpected GIC state may trigger an interrupt which we
>> are not set up to handle yet. Note that this is even the case if we enter
>> UEFI with interrupts disabled at the CPU, given that any TPL manipulation
>> involving TPL_HIGH_LEVEL will unconditionally enable IRQs at the CPU side
>> regardless of whether they were enabled to begin with (but only as soon as
>> the CPU arch protocol is actually installed)
>>
>> So let's reorder the GIC driver with the CPU driver, and let it run its
>> initialization that puts the GIC into a known state before enabling
>> interrupts. Move its installation of its IRQ handler to a protocol notify
>> callback on the CPU arch protocol so that it runs as soon as it becomes
>> available.
>>
>> Contributed-under: TianoCore Contribution Agreement 1.1
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>> ---
>>
>> This fixes an issue observed with GICv3 guests running under KVM.
>
> This fixes the problem I was seeing, so here's my:
>
> Tested-by: Marc Zyngier <marc.zyngier@arm.com>
>
> Thanks a lot Ard!
>

Pushed as 61a7b0ec634fa3288f47929ba3ced05ff48de739

Thanks.