Re: [Xen-devel] [PATCH v4 11/15] xen: arm: correctly handle sysreg accesses from userspace

[Julien Grall <julien.grall@xxxxxxxxxx>]

Hi Ian,

On 27/03/15 14:33, Ian Campbell wrote:
> Previously we implemented all registers as RAZ/WI even if they
> shouldn't be accessible to userspace.
> 
> It is not entirely clear whether attempts to access *_EL1 registers
> from EL0 will trap to EL1 or EL2, be conservative and treat as an
> undef injection.
> 
> PMUSERENR_EL0 and MDCCSR_EL0 are R/O to EL0. MDCCSR_EL0 was previously
> not handled at all.
> 
> Other PM*_EL0 registers are accessible at EL0 only if PMUSERENR_EL0.EN
> is set, since we emulate that as RAZ/WI we know that bit cannot be
> set.
> 
> Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
Reviewed-by: Julien Grall <julien.grall@xxxxxxxxxx>

Regards,

-- 
Julien Grall

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