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. --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
