Re: [PATCH] target/arm: trap DCC access in user mode emulation

[Richard Henderson]

On 6/2/23 14:43, Zhuojia Shen wrote:
> Accessing EL0-accessible Debug Communication Channel (DCC) registers in
> user mode emulation is currently enabled.  However, it does not match
> Linux behavior as Linux sets MDSCR_EL1.TDCC on startup to disable EL0
> access to DCC (see __cpu_setup() in arch/arm64/mm/proc.S).
>
> This patch fixes access_tdcc() to check MDSCR_EL1.TDCC for EL0 and sets
> MDSCR_EL1.TDCC for user mode emulation to match Linux.
>
> Signed-off-by: Zhuojia Shen <chaosdefinition@hotmail.com>

It would be nice to define the fields of MDSCR properly but either way,

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~