x86/intel_rdt: Enable L2 CDP in MSR IA32_L2_QOS_CFG

Bit 0 in MSR IA32_L2_QOS_CFG (0xc82) is L2 CDP enable bit. By default,
the bit is zero, i.e. L2 CAT is enabled, and L2 CDP is disabled. When
the resctrl mount parameter "cdpl2" is given, the bit is set to 1 and L2
CDP is enabled.

In L2 CDP mode, the L2 CAT mask MSRs are re-mapped into interleaved pairs
of mask MSRs for code (referenced by an odd CLOSID) and data (referenced by
an even CLOSID).

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com>
Cc: "Tony Luck" <tony.luck@intel.com>
Cc: Vikas" <vikas.shivappa@intel.com>
Cc: Sai Praneeth" <sai.praneeth.prakhya@intel.com>
Cc: Reinette" <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/1513810644-78015-6-git-send-email-fenghua.yu@intel.com

arch/x86/kernel/cpu/intel_rdt.h

@@ -7,12 +7,15 @@
 #include <linux/jump_label.h>
 
 #define IA32_L3_QOS_CFG		0xc81
+#define IA32_L2_QOS_CFG		0xc82
 #define IA32_L3_CBM_BASE	0xc90
 #define IA32_L2_CBM_BASE	0xd10
 #define IA32_MBA_THRTL_BASE	0xd50
 
 #define L3_QOS_CDP_ENABLE	0x01ULL
 
+#define L2_QOS_CDP_ENABLE	0x01ULL
+
 /*
  * Event IDs are used to program IA32_QM_EVTSEL before reading event
  * counter from IA32_QM_CTR