The syscall and sysret instructions behave a bit differently:
TF is checked after the instruction completes.
This allows the o/s to disable #DB at a syscall by adding TF to FMASK.
And then when the sysret is executed the #DB is taken "as if" the
syscall insn just completed.
Backports commit c52ab08aee6f7d4717fc6b517174043126bd302f from qemu
Commit 2afbdf8 ("target-i386: exception handling for memory helpers",
2015-09-15) changed tlb_fill's cpu_restore_state+raise_exception_err
to raise_exception_err_ra. After this change, the cpu_restore_state
and raise_exception_err's cpu_loop_exit are merged into
raise_exception_err_ra's cpu_loop_exit_restore.
This actually fixed some bugs, but when SVM is enabled there is a
second path from raise_exception_err_ra to cpu_loop_exit. This is
the VMEXIT path, and now cpu_vmexit is called without a
cpu_restore_state before.
The fix is to pass the retaddr to cpu_vmexit (via
cpu_svm_check_intercept_param). All helpers can now use GETPC() to pass
the correct retaddr, too.
Backports commit 823fb688ebc52a7d79c1308acb28c92b56820167 from qemu
The diff here is uglier than necessary. All this does is to turn
FOO
into:
if (s->prefix & PREFIX_LOCK) {
BAR
} else {
FOO
}
where FOO is the original implementation of an unlocked cmpxchg.
Backports commit ae03f8de45427042ecd10b0941a005f21ecc064c from qemu
This includes XSAVE, XRSTOR, XGETBV, XSETBV, which are all related,
as well as the associate cpuid bits.
Backports commit 19dc85dba23c0db1ca932c62e453c37e00761628 from qemu
Use gen_lea_v_seg for centralized segment base knowledge. Unify
code across 32- and 64-bit. Fix note about "must save state"
before using the out-of-line helpers.
Backports commit 743e398e2fbf2f7183bf7a53c9d011fabcaa1770 from qemu
Introduce helper_get_dr so that we don't have to put CR4[DE]
into the scarce HFLAGS resource. At the same time, rename
helper_movl_drN_T0 to helper_set_dr and set the helper flags.
Backports commit d0052339236072bbf08c1d600c0906126b1ab258 from qemu
In order to do this, stop using the cpu_in*/out* helpers, and instead
access address_space_io directly.
cpu_in* and cpu_out* remain for usage in the monitor, in qtest, and
in Xen.
Backports commit 3f7d84648607cc0fcb3812bb4b88978e2a7aa24f 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.
