Messages in this thread | | | Subject | Re: [PATCH 3/2] x86/microcode/intel: Add a helper which gives the microcode revision | From | Boris Ostrovsky <> | Date | Wed, 28 Dec 2016 14:26:24 -0500 |
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On 12/28/2016 07:53 AM, Borislav Petkov wrote: > On Wed, Dec 28, 2016 at 12:21:20PM +0100, Borislav Petkov wrote: >> From: Borislav Petkov <bp@suse.de> >> >> Intel supplies the microcode revision value in MSR 0x8b >> (IA32_BIOS_SIGN_ID) after CPUID(1) has been executed. Execute it each >> time before reading that MSR. > > And then, we can go a step further and even do a separate helper which does the > required steps to read out the microcode revision so that we don't forget them > next time we change the code. > > Provided that works for xen, though, because I need to do the native > variants but early_init_intel() can call the paravirt *msr() versions > and I have no idea whether that's kosher on xen pv. > > Boris, any objections?
I think this should work. MSR_IA32_UCODE_REV can be natively read and written with zero without any side effects.
-boris
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