On Sun, 2018-01-21 at 20:04 +0100, Borislav Petkov wrote: > On Sun, Jan 21, 2018 at 06:54:22PM +0000, David Woodhouse wrote: > > Because we're backporting this to every stable kernel under the > sun, > > and they don't already require asm-goto. > > Considering the cost of the barrier, I'd simplify the whole endeavor > *considerably* for backporting: > > if (boot_cpu_has(X86_FEATURE_IBPB)) > wrmsr(MSR_IA32_PRED_CMD, PRED_CMD_IBPB, 0); > > Problem solved.
Nope. Plenty of patch sets *did* have the bug above though, until it was spotted.
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