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

[Marc Zyngier <marc.zyngier@arm.com>]

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!

	M.
-- 
Jazz is not dead. It just smells funny...