Messages in this thread | | | Subject | Re: [PATCH v2] x86/microcode/intel: Blacklist the specific BDW-EP for late loading | From | "Jia Zhang" <> | Date | Mon, 25 Dec 2017 22:31:00 +0800 |
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在 2017/12/25 下午9:34, Borislav Petkov 写道: > + Tony. > > On Mon, Dec 25, 2017 at 03:49:29PM +0800, Jia Zhang wrote: >> Instead of blacklisting all Broadwell processorsi for running a late >> loading, only BDW-EP (signature 406f1) with the microcode version >> less than 0x0b000021 needs to be blacklisted. >> >> This is documented in the the public documentation #334165 (See the >> item BDF90 for details). >> >> Signed-off-by: Jia Zhang <qianyue.zj@alibaba-inc.com> >> --- >> arch/x86/kernel/cpu/microcode/intel.c | 11 +++++++++-- >> 1 file changed, 9 insertions(+), 2 deletions(-) >> >> diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c >> index 8ccdca6..f80b2dd 100644 >> --- a/arch/x86/kernel/cpu/microcode/intel.c >> +++ b/arch/x86/kernel/cpu/microcode/intel.c >> @@ -910,8 +910,15 @@ static bool is_blacklisted(unsigned int cpu) >> { >> struct cpuinfo_x86 *c = &cpu_data(cpu); >> >> - if (c->x86 == 6 && c->x86_model == INTEL_FAM6_BROADWELL_X) { >> - pr_err_once("late loading on model 79 is disabled.\n"); >> + /* >> + * The Broadwell-EP processor with the microcode version less >> + * then 0x0b000021 may reault in system hang when running a late >> + * loading. This behavior is documented in item BDF90, #334165 >> + * (Intel Xeon Processor E7-8800/4800 v4 Product Family). >> + */ >> + if (c->x86 == 6 && c->x86_model == INTEL_FAM6_BROADWELL_X && >> + c->x86_mask == 0x01 && intel_get_microcode_revision() < 0x0b000021U) { > > Actually, you shouldn't need to call intel_get_microcode_revision() here > as collect_cpu_info() has done that already and the revision is in > > c->microcode > > unless you're using the old method through do_microcode_update() and > for that you'll need to call collect_cpu_info() over all CPUs in > microcode_open(). > > So how do you update your microcode?
I used the interface /sys/devices/system/cpu/microcode/reload, not /dev/cpu/microcode.
Sound like using c->microcode is already enough. So I'm not sure why calling collect_cpu_info() is necessary for the old method. c->microcode can reflect the correct version as long as it always syncs up with the recent loaded microcode update.
Thanks, Jia
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