On 11:56 19.05.20, Brendan Shanks wrote: > The problem is that the kernel does not emulate/spoof the SLDT instruction, > only SGDT, SIDT, and SMSW. > SLDT and STR weren't thought to be commonly used, so emulation/spoofing > wasn’t added. > In the last few months I have seen reports of one or two (32-bit) Windows > games that use SLDT though. > Can you share more information about the application you’re running?
I'll try to create a very simple reproducer for this case in the next days. Unfortunately I don't have the source of the original application. I can mail you instructions about it directly, if required. > Maybe the best path is to add kernel emulation/spoofing for SLDT and > STR on 32 and 64-bit, just to cover all the cases. It should be a > pretty simple patch, I’ll start working on it. Check the other mail from Ricardo, you can probably safe that effort :-) > Alternately, I did work on a Wine patch to emulate the UMIP > instructions in user-space, but it adds a lot of code and I don’t > think there’s much appetite for it in upstream Wine (especially since > the kernel emulation is sufficient for almost all cases). > https://www.winehq.org/pipermail/wine-devel/2020-February/160027.html Yeah that seems like the less favorable effort. My best guess is that this might not be limited to Wine thus handling in the kernel might be best. > In the meantime, an easy way to disable UMIP without rebuilding the > kernel is to pass 'clearcpuid=514’ on the kernel command line. Nice, I'll use that next time :-)
