Re: [RFC PATCH 3/4] hw/intc/gic: use MxTxAttrs to divine accessing CPU

[Richard Henderson]

On 9/14/22 17:09, Alex Bennée wrote:
> Now that MxTxAttrs encodes a CPU we should use that to figure it out.
> This solves edge cases like accessing via gdbstub or qtest.
>
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/124
> ---
>   hw/intc/arm_gic.c | 39 ++++++++++++++++++++++-----------------
>   1 file changed, 22 insertions(+), 17 deletions(-)
>
> diff --git a/hw/intc/arm_gic.c b/hw/intc/arm_gic.c
> index 492b2421ab..7feedac735 100644
> --- a/hw/intc/arm_gic.c
> +++ b/hw/intc/arm_gic.c
> @@ -56,17 +56,22 @@ static const uint8_t gic_id_gicv2[] = {
>       0x04, 0x00, 0x00, 0x00, 0x90, 0xb4, 0x2b, 0x00, 0x0d, 0xf0, 0x05, 0xb1
>   };
>   
> -static inline int gic_get_current_cpu(GICState *s)
> +static inline int gic_get_current_cpu(GICState *s, MemTxAttrs attrs)
>   {
> -    if (!qtest_enabled() && s->num_cpu > 1) {
> -        return current_cpu->cpu_index;
> -    }
> -    return 0;
> +    /*
> +     * Something other than a CPU accessing the GIC would be a bug as
> +     * would a CPU index higher than the GICState expects to be
> +     * handling
> +     */
> +    g_assert(attrs.requester_cpu == 1);

Better without "== 1" -- this field ought to be boolean.

> +    g_assert(attrs.requester_id < s->num_cpu);

Do we still need the qtest_enabled test to short circuit the num_cpu test within the 
assert?  I guess if tests aren't failing then perhaps we don't...

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


r~