These include page table walks, SVM accesses and SMM state save accesses.
The bulk of the patch is obtained with
sed -i 's/\(\<[a-z_]*_phys\(_notdirty\)\?\>(cs\)->as,/x86_\1,/'
Backports commit b216aa6c0fcbaa8ff4128969c14594896a5485a4 from qemu
According to my reading of the Intel documentation, the SYSRET instruction
is supposed to force the RPL bits of the %ss register to 3 when returning
to user mode. The actual sequence is:
SS.Selector <-- (IA32_STAR[63:48]+8) OR 3; (* RPL forced to 3 *)
However, the code in helper_sysret() leaves them at 0 (in other words, the "OR
3" part of the above sequence is missing). It does set the privilege level
bits of %cs correctly though.
This has caused me trouble with some of my VxWorks development: code that runs
okay on real hardware will crash on QEMU, unless I apply the patch below.
Backports commit ac57622985220de064059971f9ccb00905e9bd04 from qemu
helper_sysenter in qemu/target-i386/seg_helper.c didn't check properly if a call interrupt callback was registred.
It has been fixed by copying the helper_syscall behavior.
