diff options
| author | Bill Paul <wpaul@windriver.com> | 2015-03-09 15:48:01 -0700 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2015-03-10 11:18:24 +0100 |
| commit | ac57622985220de064059971f9ccb00905e9bd04 (patch) | |
| tree | 0a50e0158c2c9b073881b8d2661ee90384bb8143 /exec.c | |
| parent | ae071cc851d7150d3a9950c642570830bb85729e (diff) | |
x86: fix SS selector in SYSRET
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.
Signed-off-by: Bill Paul <wpaul@windriver.com>
Message-Id: <201503091548.01462.wpaul@windriver.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'exec.c')
0 files changed, 0 insertions, 0 deletions