LINUS 本人证实苏妈的说法，在新的核心补丁里面排除了AMD的CPU
"Exclude AMD from the PTI enforcement. Not necessarily a fix, but if AMD is so c
onfident that they are not affected, then we should not burden users with the ov
erhead - x86/cpu, x86/pti: Do not enable PTI on AMD processors"
"AMD processors are not subject to the types of attacks that the kernel page tab
le isolation feature protects against. The AMD microarchitecture does not allow
memory references, including speculative references, that access higher privileg
ed data when running in a lesser privileged mode when that access would result i
n a page fault."
Linus Torvalds Trusts Lisa Su's Commitment to AMD CPU Security
http://go.newsfusion.com/security/item/1108590