Re: [Qemu-devel] [PATCH] use an unsigned long for the max_sz parameter in load_image_targphys

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

On 9 March 2012 18:47, Andreas Färber <afaerber@suse.de> wrote:
> Am 09.03.2012 18:11, schrieb Peter Maydell:
>> On 9 March 2012 14:28, Andreas Färber <afaerber@suse.de> wrote:
>>> No, please. We're describing sizes, not addresses. target_phys_addr_t
>>> thus is semantically wrong here. The RAM size is unsigned long IIRC (it
>>> is limited by the host's available memory). If you subtract something
>>> from a size it remains a size. I had therefore suggested size_t before.
>>> I expect sizeof(size_t) >= sizeof(unsigned long).
>>
>> We're discussing target sizes. size_t might be smaller than
>> target_phys_addr_t, so it's also semantically wrong. We don't
>> have a target_size_t, though, and I think "use an address
>> related type for an offset" is less bad than "use a host
>> sized type for a guest sized value".
>
> That is a moot point. There is no such thing as a "target size".

"Length of a block of memory on the guest" is what I meant.
What you need is "an integer type large enough to hold the
difference between two guest pointer values". The size of
that type should depend only on the guest config, not on the
host, so 'unsigned long', 'size_t', 'off_t' etc are all wrong.

-- PMM