Re: [PULL v2 28/86] hw/cxl/component: Add utils for interleave parameter encoding/decoding

[Peter Maydell]

On Mon, 16 May 2022 at 21:51, Michael S. Tsirkin <mst@redhat.com> wrote:
>
> From: Jonathan Cameron <jonathan.cameron@huawei.com>
>
> Both registers and the CFMWS entries in CDAT use simple encodings
> for the number of interleave ways and the interleave granularity.
> Introduce simple conversion functions to/from the unencoded
> number / size.  So far the iw decode has not been needed so is
> it not implemented.
>
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
> Message-Id: <20220429144110.25167-27-Jonathan.Cameron@huawei.com>
> Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>  include/hw/cxl/cxl_component.h |  8 ++++++++
>  hw/cxl/cxl-component-utils.c   | 34 ++++++++++++++++++++++++++++++++++
>  2 files changed, 42 insertions(+)
>
> diff --git a/include/hw/cxl/cxl_component.h b/include/hw/cxl/cxl_component.h
> index 7d8f395cbe..4f69688c47 100644
> --- a/include/hw/cxl/cxl_component.h
> +++ b/include/hw/cxl/cxl_component.h
> @@ -210,4 +210,12 @@ static inline int cxl_decoder_count_enc(int count)
>      return 0;
>  }
>
> +uint8_t cxl_interleave_ways_enc(int iw, Error **errp);
> +uint8_t cxl_interleave_granularity_enc(uint64_t gran, Error **errp);
> +
> +static inline hwaddr cxl_decode_ig(int ig)
> +{
> +    return 1 << (ig + 8);
> +}

Hi; Coverity warns about this (CID 1488868) because the shift
is calculated with 32-bit arithmetic but the function returns
a 64-bit result. I assume that 'ig' is supposed to never be
large enough that the result is >4GB, but we can make Coverity
happy by using "1ULL" here.

thanks
-- PMM