On 13/01/2018 11:27, Woodhouse, David wrote:
>> + * FIXME: this is only needed until SPEC_CTRL is supported
>> + * by upstream Linux in cpufeatures, then it can be replaced
>> + * with static_cpu_has.
> And I already shouted at Peter yesterday about static_cpu_has(). I
> refer you to my previous rant on that :)
I saw that rent and I agree---but your rant was about lfence, here I'm
not proposing to remove any lfences once KVM uses static_cpu_has:
+ /*
+ * Speculative execution past the above wrmsrl might encounter
+ * an indirect branch and use guest-controlled contents of the
+ * indirect branch predictor; block it.
+ */
+ asm("lfence");
No mention of static_cpu_has here. :)
Paolo
