Messages in this thread | | | Subject | Re: [patch RFC 5/5] x86/speculation: Add basic speculation control code | From | Dave Hansen <> | Date | Tue, 9 Jan 2018 18:02:53 -0800 |
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On 01/09/2018 05:06 PM, Thomas Gleixner wrote: > --- a/arch/x86/kernel/cpu/bugs.c > +++ b/arch/x86/kernel/cpu/bugs.c > @@ -79,6 +79,7 @@ enum spectre_v2_mitigation_cmd { > SPECTRE_V2_CMD_RETPOLINE, > SPECTRE_V2_CMD_RETPOLINE_GENERIC, > SPECTRE_V2_CMD_RETPOLINE_AMD, > + SPECTRE_V2_CMD_IBRS, > };
A few nits on this:
IBRS should not default on anywhere, which goes double when retpolines are available.
I think I'd also prefer that we separate the IBRS and retpoline enabling so that you can do both if you want. They do nearly the same thing in practice, but I can't convince myself that you never ever need IBRS once retpolines are in place.
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