On Tue, Nov 8, 2016 at 5:16 AM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > On Mon, Nov 07, 2016 at 10:12:09PM -0800, Ricardo Neri wrote: >> There is a caveat, however. Certain applications running in virtual-8086 >> mode, such as DOSEMU[1] and Wine[2], want to utilize the SGDT, SIDT and >> SLDT instructions for legitimate reasons. In order to keep such >> applications working, UMIP must be disabled/enabled when entering/exiting >> virtual-8086 mode. > > Would it not be better to emulate these instructions for them? What way > we can verify they're not malicious. Forget malice -- if they are really needed for some silly vm86-using program, let's trap them and emulate them so they return dummy values. Also, keep in mind that vm86 is already effectively gated behind a sysctl for non-root. I think the default should be that, if root has enabled vm86, it should work. --Andy -- Andy Lutomirski AMA Capital Management, LLC -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
