Re: [PATCH] docs/about: Update the support statement for Windows

[Thomas Huth <thuth@redhat.com>]

On 05/05/2022 17.09, Daniel P. Berrangé wrote:
> On Thu, May 05, 2022 at 04:12:11PM +0200, Thomas Huth wrote:
>> On 05/05/2022 13.55, Daniel P. Berrangé wrote:
>>> On Thu, May 05, 2022 at 09:14:57AM +0100, Daniel P. Berrangé wrote:
>>>> On Thu, May 05, 2022 at 09:48:41AM +0200, Thomas Huth wrote:
>>>>> Our support statement for Windows currently talks about "Vista / Server
>>>>> 2008" - which is related to the API of Windows, and this is not easy
>>>>> to understand for the non-technical users. It might also not be quite
>>>>> true anymore, since we only compile-test QEMU with recent toolchains.
>>>>
>>>> We documented Vista / Server 2008 because that is what our code is
>>>> declaring it wants in terms of Windows public APIs:
>>>>
>>>> In osdep.h we have:
>>>>
>>>>     #ifdef _WIN32
>>>>     /* as defined in sdkddkver.h */
>>>>     #ifndef _WIN32_WINNT
>>>>     #define _WIN32_WINNT 0x0600 /* Vista */
>>>>     #endif
>>>>
>>>> which tells Mingw / MSys not to expose windows header file declarations
>>>> that post-date Vista.
>>>
>>> Of course we rely on 3rd party libraries and in particular GLib2 is
>>> mandatory, and it also set _WIN32_WINNT. So our constraint is the
>>> newer of the _WIN32_WINNT constraint set by QEMU and whatever version
>>> of GLib2 being compiled against.
>>>
>>> QEMU sets a min GLib of 2.56, and that version of GLib sets 0x0601
>>> which means Windows >= 7.  So even though QEMU only asks for Vista,
>>> in practice our minimum is 7.
>>
>> Windows 7 does not receive any security updates since 2020 anymore, so I'd
>> rather would bump it to the level of Windows 8.1 directly instead. Or
>> directly go for Windows 10 to mimic the behavior that we have with most of
>> the Linux distros (max. two major releases at a time).
> 
> I like the simplicity of having the same rule everywhere.
> 
> I'm a little wary of people being stuck on old versions, when I see
> current articles like this showing 20% of people still on Win7, way
> more than Win8 surprisingly.
> 
> https://www.statista.com/statistics/993868/worldwide-windows-operating-system-market-share/

I still think it would be better to not provide QEMU to people who fail to 
make sure that their host system is up to date with security patches...

> The thing with bumping the _WIN32_WINNT version higher though is that
> we're not really doing it for any compelling technical reasons. Usually
> when we bump min glib, it lets us cut out compatibility hacks and/or
> get access to new APIs.
> 
> Bumping _WIN32_WINNT can do that, but the interesting place where that's
> useful is mostly in GLib. I'm not sure what we'd make use of in the QEMU
> side from setting a newer _WIN32_WINNT. Hence my suggestion that we just
> let min GLib drive our min _WIN32_WINNT setting.

Ok, fair point. So let's raise the WIN32_WINNT setting to the same level as 
glib - but I think our support statement in our docs could be independent 
from that... I'll try to come up with a different phrasing in v2 of this patch.

  Thomas