Messages in this thread | | | Subject | Re: [PATCH 1/4] x86/speculation: Use IBRS if available before calling into firmware | From | David Woodhouse <> | Date | Wed, 14 Feb 2018 16:53:39 +0000 |
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On Wed, 2018-02-14 at 10:36 -0600, Tom Lendacky wrote: > On 2/14/2018 10:11 AM, David Woodhouse wrote: > > > > > > > > On Wed, 2018-02-14 at 10:07 -0600, Tom Lendacky wrote: > > > > > > Shouldn't these writes to the MSR be just for the IBRS bit? The spec > > > also defines the STIBP bit for this MSR, and if that bit had been set by > > > BIOS for example, these writes will clear it. And who knows what future > > > bits may be defined and how they'll be used. > > > > We don't use STIBP. If one day we do decide to set it in userspace for > > Right, I understand the kernel doesn't use STIBP, that's why I mentioned > BIOS as an example.
BIOS has no business setting this for us either. Either we support it and turn it on in the kernel ourselves, or it's off.[unhandled content-type:application/x-pkcs7-signature]
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