Re: [PATCH] x86/kconfig/32: Mark CONFIG_VM86 as BROKEN

[Andy Lutomirski]

On Fri, Jul 10, 2015 at 4:16 AM, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
>
>
> On 09/07/2015 20:33, Andy Lutomirski wrote:
>> On Wed, Jul 8, 2015 at 10:59 PM, Ingo Molnar <mingo@xxxxxxxxxx> wrote:
>
>> The big downside of that, or of writing a more ad-hoc emulator, is
>> understanding what the semantics of all the weird vm86plus stuff is
>> supposed to be in the first place.
>
> Do you mean VIF/VIP and the other vm86 mode extensions?  Or is vm86plus
> something in Linux?

Something in Linux written for DOSEMU's benefit.  I don't really
understand what it encompasses.  Oddly, Linux doesn't use the virtual
mode extensions.  Instead, it emulates them (but probably not very
well).  So STI manipulates a fake VIF flag and checks a fake VIP flag.

There's also a huge hack involving 0xA0000.

--Andy
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