Re: [RFC 1/2] hw/ppc/ppc440_uc: Initialize length passed to cpu_physical_memory_map()

[Peter Maydell <peter.maydell@linaro.org>]

On Tue, 26 Jul 2022 at 19:23, Peter Maydell <peter.maydell@linaro.org> wrote:
>
> In dcr_write_dma(), there is code that uses cpu_physical_memory_map()
> to implement a DMA transfer.  That function takes a 'plen' argument,
> which points to a hwaddr which is used for both input and output: the
> caller must set it to the size of the range it wants to map, and on
> return it is updated to the actual length mapped. The dcr_write_dma()
> code fails to initialize rlen and wlen, so will end up mapping an
> unpredictable amount of memory.
>
> Initialize the length values correctly, and check that we managed to
> map the entire range before using the fast-path memmove().
>
> This was spotted by Coverity, which points out that we never
> initialized the variables before using them.
>
> Fixes: Coverity CID 1487137

Also CID 1487150 (it reports the wlen and rlen issues separately).

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

-- PMM