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Date: Fri, 27 Sep 2013 00:13:22 +0200 From: Borislav Petkov <bp@...en8.de> To: suravee.suthikulpanit@....com Cc: herrmann.der.user@...glemail.com, jacob.w.shin@...il.com, linux-kernel@...r.kernel.org Subject: Re: [PATCH] x86, microcode, AMD: Fix patch level reporting for family15h On Thu, Sep 26, 2013 at 04:54:32PM -0500, suravee.suthikulpanit@....com wrote: > From: Suravee Suthikulpanit <suravee.suthikulpanit@....com> > > On AMD family15h, applying microcode patch on the a core (core0) > would also affect the other core (core1) in the same compute unit. > The driver would skip applying the patch on core1, but it still > need to update kernel structures to reflect the proper patch level. > > The current logic is not updating the struct ucode_cpu_info.cpu_sig.rev > of the skipped core. This causes the /sys/devices/system/cpu/cpu1/microcode/version > to report incorrect patch level as shown below: > > [ 10.708841] microcode: CPU0: new patch_level=0x0600063d > [ 10.714256] microcode: CPU1: patch_level=0x06000626 > [ 10.719345] microcode: CPU2: patch_level=0x06000626 > [ 10.748095] microcode: CPU2: new patch_level=0x0600063d > [ 10.753365] microcode: CPU3: patch_level=0x06000626 > [ 10.758264] microcode: CPU4: patch_level=0x06000626 > [ 10.786999] microcode: CPU4: new patch_level=0x0600063d Actually, this is collect_cpu_info_amd()'s normal operation and shows that there's no need to apply a microcode patch on the odd core since the even core's ucode has been updated. Actually you need something like that: $ grep . cpu?/microcode/version cpu0/microcode/version:0x6000822 cpu1/microcode/version:0x600081f cpu2/microcode/version:0x6000822 cpu3/microcode/version:0x600081f cpu4/microcode/version:0x6000822 cpu5/microcode/version:0x600081f cpu6/microcode/version:0x6000822 cpu7/microcode/version:0x600081f which shows the bug. Other than that, the patch is correct so please fix the commit message and add x86@...nel.org to CC on the next submission so that it gets picked by x86 people. Thanks. -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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