Re: [PATCH 10/14] hw/intc/arm_gicv3_its: Provide read accessor for translation_ops

[Philippe Mathieu-Daudé]

On 22/1/22 19:24, Peter Maydell wrote:
> The MemoryRegionOps gicv3_its_translation_ops currently provides only
> a .write_with_attrs function, because the only register in this
> region is the write-only GITS_TRANSLATER.  However, if you don't
> provide a read function and the guest tries reading from this memory
> region, QEMU will crash because
> memory_region_read_with_attrs_accessor() calls a NULL pointer.
>
> Add a read function which always returns 0, to cover both bogus
> attempts to read GITS_TRANSLATER and also reads from the rest of the
> region, which is documented to be reserved, RES0.
>
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>   hw/intc/arm_gicv3_its.c | 13 +++++++++++++
>   1 file changed, 13 insertions(+)

> +static MemTxResult gicv3_its_translation_read(void *opaque, hwaddr offset,
> +                                              uint64_t *data, unsigned size,
> +                                              MemTxAttrs attrs)
> +{
> +    /*
> +     * GITS_TRANSLATER is write-only, and all other addresses
> +     * in the interrupt translation space frame are RES0.
> +     */
> +    *data = 0;

Maybe log GUEST_ERROR?

Otherwise,
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

> +    return MEMTX_OK;
> +}