x86/speculation: Remove Skylake C2 from Speculation Control microcode blacklist

commit e3b3121fa8da94cb20f9e0c64ab7981ae47fd085 upstream.

In accordance with Intel's microcode revision guidance from March 6 MCU
rev 0xc2 is cleared on both Skylake H/S and Skylake Xeon E3 processors
that share CPUID 506E3.

Signed-off-by: Alexander Sergeyev <sergeev917@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jia Zhang <qianyue.zj@alibaba-inc.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kyle Huey <me@kylehuey.com>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Link: https://lkml.kernel.org/r/20180313193856.GA8580@localhost.localdomain
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Srivatsa S. Bhat <srivatsa@csail.mit.edu>
Reviewed-by: Matt Helsley (VMware) <matt.helsley@gmail.com>
Reviewed-by: Alexey Makhalov <amakhalov@vmware.com>
Reviewed-by: Bo Gan <ganb@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index dcc0349..77d9f68 100644 (file)
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -29,7 +29,7 @@
 /*
  * Early microcode releases for the Spectre v2 mitigation were broken.
  * Information taken from;
- * - https://newsroom.intel.com/wp-content/uploads/sites/11/2018/01/microcode-update-guidance.pdf
+ * - https://newsroom.intel.com/wp-content/uploads/sites/11/2018/03/microcode-update-guidance.pdf
  * - https://kb.vmware.com/s/article/52345
  * - Microcode revisions observed in the wild
  * - Release note from 20180108 microcode release
@@ -47,7 +47,6 @@ static const struct sku_microcode spectre_bad_microcodes[] = {
        { INTEL_FAM6_KABYLAKE_MOBILE,   0x09,   0x80 },
        { INTEL_FAM6_SKYLAKE_X,         0x03,   0x0100013e },
        { INTEL_FAM6_SKYLAKE_X,         0x04,   0x0200003c },
-       { INTEL_FAM6_SKYLAKE_DESKTOP,   0x03,   0xc2 },
        { INTEL_FAM6_BROADWELL_CORE,    0x04,   0x28 },
        { INTEL_FAM6_BROADWELL_GT3E,    0x01,   0x1b },
        { INTEL_FAM6_BROADWELL_XEON_D,  0x02,   0x14 },