[PATCH v2 5/7] arm64: KVM: vgic-v2: Add the GICV emulation infrastructure

[Christoffer Dall]

On Tue, Sep 06, 2016 at 09:28:45AM +0100, Marc Zyngier wrote:
> In order to efficiently perform the GICV access on behalf of the
> guest, we need to be able to avoid going back all the way to
> the host kernel.
> 
> For this, we introduce a new hook in the world switch code,
> conveniently placed just after populating the fault info.
> At that point, we only have saved/restored the GP registers,
> and we can quickly perform all the required checks (data abort,
> translation fault, valid faulting syndrome, not an external
> abort, not a PTW).
> 
> Coming back from the emulation code, we need to skip the emulated
> instruction. This involves an additional bit of save/restore in
> order to be able to access the guest's PC (and possibly CPSR if
> this is a 32bit guest).
> 
> At this stage, no emulation code is provided.
> 
> Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>

Reviewed-by: Christoffer Dall <christoffer.dall at linaro.org>