On Thu, 2017-03-09 at 18:39 -0800, Andy Lutomirski wrote: > On Thu, Mar 9, 2017 at 2:10 PM, Stas Sergeev <stsp@xxxxxxx> wrote: > > 09.03.2017 04:15, Ricardo Neri пишет: > > > >> On Wed, 2017-03-08 at 08:46 -0800, Andy Lutomirski wrote: > >>> > >>> On Wed, Mar 8, 2017 at 8:29 AM, Stas Sergeev <stsp@xxxxxxx> wrote: > >>>> > >>>> 08.03.2017 19:06, Andy Lutomirski пишет: > >>>>> > >>>>> On Wed, Mar 8, 2017 at 6:08 AM, Stas Sergeev <stsp@xxxxxxx> wrote: > >>>>>> > >>>>>> 08.03.2017 03:32, Ricardo Neri пишет: > >>>>>>> > >>>>>>> These are the instructions covered by UMIP: > >>>>>>> * SGDT - Store Global Descriptor Table > >>>>>>> * SIDT - Store Interrupt Descriptor Table > >>>>>>> * SLDT - Store Local Descriptor Table > >>>>>>> * SMSW - Store Machine Status Word > >>>>>>> * STR - Store Task Register > >>>>>>> > >>>>>>> This patchset initially treated tasks running in virtual-8086 > >>> > >>> mode as a > >>>>>>> > >>>>>>> special case. However, I received clarification that DOSEMU[8] > >>> > >>> does not > >>>>>>> > >>>>>>> support applications that use these instructions. > >>>>> > >>>>> Can you remind me what was special about it? It looks like you > >>> > >>> still > >>>>> > >>>>> emulate them in v8086 mode. > >>>> > >>>> Indeed, sorry, I meant prot mode here. :) > >>>> So I wonder what was cited to be special about v86. > >> > >> Initially my patches disabled UMIP on virtual-8086 instructions, without > >> regards of protected mode (i.e., UMIP was always enabled). I didn't have > >> emulation at the time. Then, I added emulation code that now covers > >> protected and virtual-8086 modes. I guess it is not special anymore. > > > > But isn't SLDT&friends just throw UD in v86? > > How does UMIP affect this? How does your patch affect > > this? > > Er, right. Ricardo, your code may need fixing. But don't you have a > test case for this? The behavior should be the same with and without > your patches applied. The exception is #UD, not #GP, so maybe your > code just never executes in the vm86 case. Ouch! Yes, I am afraid my code will attempt to emulate sldt in vm86 mode. The test cases that I have for vm86 are only for the instructions that are valid in vm86: smsw, sidt and sgdt. I will add test cases for str and sldt and make sure that a #UD is issued. Would this trigger a v7 series? Thanks and BR, Ricardo > > --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-msdos" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
