Messages in this thread | | | Date | Fri, 19 Aug 2022 10:47:21 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH] x86/speculation: Avoid LFENCE in FILL_RETURN_BUFFER on CPUs that lack it |
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On Fri, Aug 19, 2022 at 02:33:08AM +0200, Ben Hutchings wrote: > From: Ben Hutchings <benh@debian.org> > > The mitigation for PBRSB includes adding LFENCE instructions to the > RSB filling sequence. However, RSB filling is done on some older CPUs > that don't support the LFENCE instruction. >
Wait; what? There are chips that enable the RSB mitigations and DONT have LFENCE ?!?
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