Re: [PATCH v1 8/8] xen/arm: vgic-v3: Support 32-bit access for 64-bit registers

[Ian Campbell <ian.campbell@citrix.com>]

On Fri, 2015-09-25 at 15:51 +0100, Julien Grall wrote:
> Based on 8.1.3 (IHI 0069A), unless stated otherwise, the 64-bit registers
> supports both 32-bit and 64-bits access.


> 
> All the registers we properly emulate (i.e not RAZ/WI) supports 32-bit
> access.
> 
> For RAZ/WI, it's also seems to be the case but I'm not 100% sure. Anyway,
> emulating 32-bit access for them doesn't hurt. Note that we would need
> some extra care when they will be implemented (for instance
> GICR_PROPBASER).
> 
> Signed-off-by: Julien Grall <julien.grall@citrix.com>

Acked-by: Ian Campbell <ian.campbell@citrix.com>

> ---
>     This is technically fixing boot of FreeBSD ARM64 guest with GICv3.
> 
>     AFAICT, Linux is not using 32-bit access in the GICv3 code expect
>     for the ITS (which we don't support yet).
> 
>     So this patch is a good candiate for Xen 4.6. Although this patch is
>     heavily depend on previous patches. It may be possible to shuffle
>     and move the "opmitization" patches towards the end. I haven't yet
>     done that because I feel this series makes more sense in the current
>     order.

I think if we let it bake in unstable for a bit to gain confidence we could
consider backporting the whole lot to either 4.6.1 or .2.