Re: [PATCH v3 07/10] xen/arm: Always access SCTLR_EL2 using READ/WRITE_SYSREG()

[Julien Grall <julien@xxxxxxx>]

Hi Michal,

On 05/05/2021 08:43, Michal Orzel wrote:
> The Armv8 specification describes the system register as a 64-bit value
> on AArch64 and 32-bit value on AArch32 (same as ARMv7).
>
> Unfortunately, Xen is accessing the system registers using
> READ/WRITE_SYSREG32() which means the top 32-bit are clobbered.
>
> This is only a latent bug so far because Xen will not yet use the top
> 32-bit.
>
> There is also no change in behavior because arch/arm/arm64/head.S will
> initialize SCTLR_EL2 to a sane value with the top 32-bit zeroed.
>
> Signed-off-by: Michal Orzel <michal.orzel@xxxxxxx>
Acked-by: Julien Grall <jgrall@xxxxxxxxxx>

Cheers,

--
Julien Grall