Re: [tip:x86/urgent] x86-64, modify_ldt: Ban 16-bit segments on 64-bit kernels

Brian Gerst
2014-04-11T18:45:19Z

On Fri, Apr 11, 2014 at 2:41 PM, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
> On Fri, Apr 11, 2014 at 11:27 AM, Brian Gerst <brgerst@gmail.com> wrote:
>> Is this bug really still present in modern CPUs? This change breaks
>> running 16-bit apps in Wine. I have a few really old games I like to
>> play on occasion, and I don't have a copy of Win 3.11 to put in a VM.
>
> Ok, so you actually do this on x86-64, and it currently works? For
> some reason I thought that 16-bit windows apps already didn't work.
>
> Because if we have working users of this, then I don't think we can do
> the "we don't support 16-bit segments", or at least we need to make it
> runtime configurable.
>
> Linus

I haven't tested it recently but I do know it has worked on 64-bit
kernels. There is no reason for it not to, the only thing not
supported in long mode is vm86. 16-bit protected mode is unchanged.