Hi, On Mon, Nov 13, 2023 at 7:44 AM Eric Auer via Freedos-devel <freedos-devel@lists.sourceforge.net> wrote: > > > Hi! I just got reminded that (2017 news) > > http://www.os2museum.com/wp/vme-broken-on-amd-ryzen/ > > VME is broken on AMD Ryzen of that time
Ryzen (Zen 1) was brand new in 2017, redesigned from scratch. I doubt the current Zen 4 (2022) has that bug, but who knows. (Now that the BIOS and CSM are dead, they may not care to fix it. And the whole "x86-S" rumors imply legacy is going away.) > That sounds like > something which would be relevant for JEMM386, because it > could automatically activate NOVME mode for affected CPU. It's faster with VME (on Pentium and up), right? > Does anybody remember whether it does? * https://github.com/Baron-von-Riedesel/Jemm/releases v5.79 (Oct 31, 2020) "VME (virtual mode extensions) is now off by default; there exist CPUs that claim to support VME but actually don't." > And whether AMD has fixed the issue in later Ryzen or other CPU versions? Not sure. I'll search Google. * https://wiki.gentoo.org/wiki/Ryzen "Broken VME (Virtual-8086 Mode Enhancements) on 1st gen Ryzen 1st Ryzen processors generation had a broken VME implementation: 16-bits VM86 tasks within a 32-bits protected mode OS crash. This has been fixed by a later microcode revision" * http://www.os2museum.com/wp/vme-fixed-on-amd-ryzen/ Odd, the fix was mentioned on OS/2 Museum (in 2017, again). "The fix is shipped in the form of a microcode patch as part of AGESA 1.0.0.6, currently being rolled out by OEMs as part of a BIOS update. The patch level for the fixed microcode is 8001126 or higher. The older microcode revision 800111C (part of AGESA 1.0.0.4a) is known to have trouble with VME." But looking at this VOGONS thread, I'm unsure: * https://www.vogons.org/viewtopic.php?t=53952&start=20 _______________________________________________ Freedos-devel mailing list Freedos-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-devel
