sysenter/sysexit are not supported on AMD's 32bit compat mode, whereas syscall is not supported on Intel's 32bit compat mode. To allow cross vendor migration we emulate the missing instructions by setting up the processor state accordingly. The sysenter code was originally sketched by Amit Shah, it was completed, debugged, syscall added and made-to-work by Christoph Egger and polished up by Andre Przywara. Please note that sysret does not need to be emulated, because it will be exectued in 64bit mode and returning to 32bit compat mode works on Intel.
This has been tested with GETPIDs in a tight loop in compat mode on both Intel and AMD boxes. Additionally a 32-bit userland was booted under a 64-bit kernel and then cross-vendor migrated. Please apply or comment ;-) Regards, Andre. Signed-off-by: Amit Shah <amit.s...@redhat.com> Signed-off-by: Christoph Egger <christoph.eg...@amd.com> Signed-off-by: Andre Przywara <andre.przyw...@amd.com> -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
