Re: [PATCH v2 1/2] x86_64,entry: Filter RFLAGS.NT on entry from userspace

Sebastian Lackner
2014-10-01T05:09:25Z

> + testl $X86_EFLAGS_NT,EFLAGS(%rsp) /* saved EFLAGS match cpu */
> + jz 1f
> + pushq_cfi $(X86_EFLAGS_IF|X86_EFLAGS_FIXED)
> + popfq_cfi
> +1:
> +

Do you think it makes sense to change the order here, so that no jump happens if
NT is not set (which happens a bit more often, than the other way round)? Just a
guess though, haven't measured if pipeline effects have such a big influence in this
case. ;)