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

[Brian Gerst]

On Fri, Apr 11, 2014 at 2:41 PM, Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> On Fri, Apr 11, 2014 at 11:27 AM, Brian Gerst <brgerst@xxxxxxxxx> 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.
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