Messages in this thread | | | From | Nick Lowe <> | Date | Fri, 16 Feb 2018 13:15:06 +0000 | Subject | Re: [PATCH 4.9 43/92] x86/pti: Do not enable PTI on CPUs which are not vulnerable to Meltdown |
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Hi
I do not have a tested patch, but I expect the change would be something like:
skip: - if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) + if (!static_cpu_has_bug(X86_BUG_CPU_MELTDOWN)) goto disable;
Cheers,
Nick
On Tue, Feb 13, 2018 at 4:32 PM, Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote: > On Tue, Feb 13, 2018 at 03:27:47PM +0000, Nick Lowe wrote: >> Hi Arjan and Greg, >> >> Sorry if I am not being clear enough. >> >> My point is that there is a check for X86_VENDOR_AMD now in two places. >> >> It is still hardcoded for the auto boot option which I think should >> not be there. The patch on that basis looked incomplete to me. >> >> Put another way, there is no effect to the auto option where the >> contents of cpu_no_meltdown[] are changed and >> cpu_vulnerable_to_meltdown returns differently. >> >> The auto option does not make use of a determination of the >> X86_BUG_CPU_MELTDOWN state. >> >> This seems wrong to me. It does not seem correct to me for the auto >> option to have this duplication with a check for just X86_VENDOR_AMD. > > Do you have a patch that reflects what you want to see changed here? > > And can you test it? :) > > I don't have any AMD hardware, sorry. > > thanks, > > greg k-h
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