Messages in this thread | | | From | "H. Peter Anvin" <> | Date | Wed, 08 Nov 2017 08:38:18 -0800 | Subject | Re: [tip:x86/asm] x86/umip: Add emulation code for UMIP instructions |
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<linux-tip-commits@vger.kernel.org> From: hpa@zytor.com Message-ID: <67A3DB9F-E58D-42B3-BF16-AC59D2FCECC2@zytor.com>
On November 8, 2017 8:34:45 AM PST, Linus Torvalds <torvalds@linux-foundation.org> wrote: >On Wed, Nov 8, 2017 at 8:14 AM, Denys Vlasenko <dvlasenk@redhat.com> >wrote: >> >> Can we avoid maintain emulation of these isns, by asking Wine to >remove >> their use instead? > >If we ask the Wine people to remove the instruction use, that may mean >that we can avoid the emulation in four or five _years_ once everybody >has updated. > >But it wouldn't mean that we could avoid it today. > >We *do* probably want to print a warning about these instructions, >whether emulated or not. If emulated, we want to print a warning about >the emulation being expensive (as a nudge to the Wine people to not do >that), and if _not_ emulated, we'd want to print a warning about why >people suddenly got a SIGSEGV in case there are programs that use >those instructions that people didn't even think of. > >But make it ratelimit the warning (perhaps at most once every few >minutes or whatever), so that people won't flood message logs just >because they have old stupid programs that use those things. > > Linus
The real problem is that 16-bit software uses the instructions mostly for stupid reasons, but smsw in particular is used exactly because it is a virtualization hole. -- Sent from my Android device with K-9 Mail. Please excuse my brevity.
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