Re: [Qemu-devel] [PATCH] hw/net/dp8393x: Avoid unintentional sign extensions on addresses

From: Jason Wang <jasowang@redhat.com>
To: Peter Maydell <peter.maydell@linaro.org>, qemu-devel@nongnu.org
Cc: patches@linaro.org, "Laurent Vivier" <laurent@vivier.eu>,
	"Hervé Poussineau" <hpoussin@reactos.org>,
	"Aurelien Jarno" <aurelien@aurel32.net>
Subject: Re: [Qemu-devel] [PATCH] hw/net/dp8393x: Avoid unintentional sign extensions on addresses
Date: Wed, 11 Jan 2017 11:05:40 +0800	[thread overview]
Message-ID: <a6125614-cdd3-bacf-b0ff-786eec007baa@redhat.com> (raw)
In-Reply-To: <1483987437-12084-1-git-send-email-peter.maydell@linaro.org>

On 2017年01月10日 02:43, Peter Maydell wrote:
> The dp8393x has several 32-bit values which are formed by concatenating
> two 16 bit device register values. Attempting to do these inline
> with ((s->reg[HI] << 16) | s->reg[LO]) can result in an unintended
> sign extension because "x << 16" is of type 'int' even though s->reg
> is unsigned, and so if the expression is used in a context where
> it is cast to uint64_t the value is incorrectly sign-extended.
> Fix this by using accessor functions with a uint32_t return type;
> this also makes the code a bit easier to read.
>
> This should fix Coverity issues 1307765, 1307766, 1307767, 1307768.
>
> (To avoid having a ctda read function only used in a DPRINTF,
> we move the DPRINTF down slightly so it can use the ttda function.)
>
> Signed-off-by: Peter Maydell<peter.maydell@linaro.org>
> ---
> Disclaimer: only compile tested as this device only exists on
> the MIPS magnum/pica61 boards and I don't have an image for them.

Applied to -net.

Thanks