Re: [PATCH v2] softmmu: Always initialize xlat in address_space_translate_for_iotlb

[Peter Maydell]

On Tue, 21 Jun 2022 at 16:38, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> The bug is an uninitialized memory read, along the translate_fail
> path, which results in garbage being read from iotlb_to_section,
> which can lead to a crash in io_readx/io_writex.
>
> The bug may be fixed by writing any value with zero
> in ~TARGET_PAGE_MASK, so that the call to iotlb_to_section using
> the xlat'ed address returns io_mem_unassigned, as desired by the
> translate_fail path.
>
> It is most useful to record the original physical page address,
> which will eventually be logged by memory_region_access_valid
> when the access is rejected by unassigned_mem_accepts.
>
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1065
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM