x86/intel_rdt: Add command line options for resource director technology

Command line options allow us to ignore features that we don't want.
Also we can re-enable options that have been disabled on a platform
(so long as the underlying h/w actually supports the option).

[ tglx: Marked the option array __initdata and the helper function __init ]

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Fenghua" <fenghua.yu@intel.com>
Cc: Ravi V" <ravi.v.shankar@intel.com>
Cc: "Peter Zijlstra" <peterz@infradead.org>
Cc: "Stephane Eranian" <eranian@google.com>
Cc: "Andi Kleen" <ak@linux.intel.com>
Cc: "David Carrillo-Cisneros" <davidcc@google.com>
Cc: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Link: http://lkml.kernel.org/r/0c37b0d4dbc30977a3c1cee08b66420f83662694.1503512900.git.tony.luck@intel.com

3 files changed, 95 insertions, 8 deletions

diff --git a/Documentation/admin-guide/kernel-parameters.rst b/Documentation/admin-guide/kernel-parameters.rst
index d76ab3907e2b..b2598cc9834c 100644
--- a/Documentation/admin-guide/kernel-parameters.rst
+++ b/Documentation/admin-guide/kernel-parameters.rst
@@ -138,6 +138,7 @@ parameter is applicable::
         PPT     Parallel port support is enabled.
         PS2     Appropriate PS/2 support is enabled.
         RAM     RAM disk support is enabled.
+        RDT     Intel Resource Director Technology.
         S390    S390 architecture is enabled.
         SCSI    Appropriate SCSI support is enabled.
                         A lot of drivers have their options described inside
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index d9c171ce4190..ef52ae4ed6e8 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3598,6 +3598,12 @@
                         Run specified binary instead of /init from the ramdisk,
                         used for early userspace startup. See initrd.
 
+        rdt=            [HW,X86,RDT]
+                        Turn on/off individual RDT features. List is:
+                        cmt, mbmtotal, mbmlocal, l3cat, l3cdp, l2cat, mba.
+                        E.g. to turn on cmt and turn off mba use:
+                                rdt=cmt,!mba
+
         reboot=         [KNL]
                         Format (x86 or x86_64):
                                 [w[arm] | c[old] | h[ard] | s[oft] | g[pio]] \
diff --git a/arch/x86/kernel/cpu/intel_rdt.c b/arch/x86/kernel/cpu/intel_rdt.c
index 25514cd454b3..b641622003cf 100644
--- a/arch/x86/kernel/cpu/intel_rdt.c
+++ b/arch/x86/kernel/cpu/intel_rdt.c
@@ -637,6 +637,85 @@ static __init void rdt_init_padding(void)
         }
 }
 
+enum {
+        RDT_FLAG_CMT,
+        RDT_FLAG_MBM_TOTAL,
+        RDT_FLAG_MBM_LOCAL,
+        RDT_FLAG_L3_CAT,
+        RDT_FLAG_L3_CDP,
+        RDT_FLAG_L2_CAT,
+        RDT_FLAG_MBA,
+};
+
+#define RDT_OPT(idx, n, f)      \
+[idx] = {                       \
+        .name = n,              \
+        .flag = f               \
+}
+
+struct rdt_options {
+        char    *name;
+        int     flag;
+        bool    force_off, force_on;
+};
+
+static struct rdt_options rdt_options[]  __initdata = {
+        RDT_OPT(RDT_FLAG_CMT,       "cmt",      X86_FEATURE_CQM_OCCUP_LLC),
+        RDT_OPT(RDT_FLAG_MBM_TOTAL, "mbmtotal", X86_FEATURE_CQM_MBM_TOTAL),
+        RDT_OPT(RDT_FLAG_MBM_LOCAL, "mbmlocal", X86_FEATURE_CQM_MBM_LOCAL),
+        RDT_OPT(RDT_FLAG_L3_CAT,    "l3cat",    X86_FEATURE_CAT_L3),
+        RDT_OPT(RDT_FLAG_L3_CDP,    "l3cdp",    X86_FEATURE_CDP_L3),
+        RDT_OPT(RDT_FLAG_L2_CAT,    "l2cat",    X86_FEATURE_CAT_L2),
+        RDT_OPT(RDT_FLAG_MBA,       "mba",      X86_FEATURE_MBA),
+};
+#define NUM_RDT_OPTIONS ARRAY_SIZE(rdt_options)
+
+static int __init set_rdt_options(char *str)
+{
+        struct rdt_options *o;
+        bool force_off;
+        char *tok;
+
+        if (*str == '=')
+                str++;
+        while ((tok = strsep(&str, ",")) != NULL) {
+                force_off = *tok == '!';
+                if (force_off)
+                        tok++;
+                for (o = rdt_options; o < &rdt_options[NUM_RDT_OPTIONS]; o++) {
+                        if (strcmp(tok, o->name) == 0) {
+                                if (force_off)
+                                        o->force_off = true;
+                                else
+                                        o->force_on = true;
+                                break;
+                        }
+                }
+        }
+        return 1;
+}
+__setup("rdt", set_rdt_options);
+
+static bool __init rdt_cpu_has(int flag)
+{
+        bool ret = boot_cpu_has(flag);
+        struct rdt_options *o;
+
+        if (!ret)
+                return ret;
+
+        for (o = rdt_options; o < &rdt_options[NUM_RDT_OPTIONS]; o++) {
+                if (flag == o->flag) {
+                        if (o->force_off)
+                                ret = false;
+                        if (o->force_on)
+                                ret = true;
+                        break;
+                }
+        }
+        return ret;
+}
+
 static __init bool get_rdt_alloc_resources(void)
 {
         bool ret = false;
@@ -647,21 +726,21 @@ static __init bool get_rdt_alloc_resources(void)
         if (!boot_cpu_has(X86_FEATURE_RDT_A))
                 return false;
 
-        if (boot_cpu_has(X86_FEATURE_CAT_L3)) {
+        if (rdt_cpu_has(X86_FEATURE_CAT_L3)) {
                 rdt_get_cache_alloc_cfg(1, &rdt_resources_all[RDT_RESOURCE_L3]);
-                if (boot_cpu_has(X86_FEATURE_CDP_L3)) {
+                if (rdt_cpu_has(X86_FEATURE_CDP_L3)) {
                         rdt_get_cdp_l3_config(RDT_RESOURCE_L3DATA);
                         rdt_get_cdp_l3_config(RDT_RESOURCE_L3CODE);
                 }
                 ret = true;
         }
-        if (boot_cpu_has(X86_FEATURE_CAT_L2)) {
+        if (rdt_cpu_has(X86_FEATURE_CAT_L2)) {
                 /* CPUID 0x10.2 fields are same format at 0x10.1 */
                 rdt_get_cache_alloc_cfg(2, &rdt_resources_all[RDT_RESOURCE_L2]);
                 ret = true;
         }
 
-        if (boot_cpu_has(X86_FEATURE_MBA)) {
+        if (rdt_cpu_has(X86_FEATURE_MBA)) {
                 if (rdt_get_mem_config(&rdt_resources_all[RDT_RESOURCE_MBA]))
                         ret = true;
         }
@@ -670,11 +749,11 @@ static __init bool get_rdt_alloc_resources(void)
 
 static __init bool get_rdt_mon_resources(void)
 {
-        if (boot_cpu_has(X86_FEATURE_CQM_OCCUP_LLC))
+        if (rdt_cpu_has(X86_FEATURE_CQM_OCCUP_LLC))
                 rdt_mon_features |= (1 << QOS_L3_OCCUP_EVENT_ID);
-        if (boot_cpu_has(X86_FEATURE_CQM_MBM_TOTAL))
+        if (rdt_cpu_has(X86_FEATURE_CQM_MBM_TOTAL))
                 rdt_mon_features |= (1 << QOS_L3_MBM_TOTAL_EVENT_ID);
-        if (boot_cpu_has(X86_FEATURE_CQM_MBM_LOCAL))
+        if (rdt_cpu_has(X86_FEATURE_CQM_MBM_LOCAL))
                 rdt_mon_features |= (1 << QOS_L3_MBM_LOCAL_EVENT_ID);
 
         if (!rdt_mon_features)
@@ -687,7 +766,8 @@ static __init void rdt_quirks(void)
 {
         switch (boot_cpu_data.x86_model) {
         case INTEL_FAM6_HASWELL_X:
-                cache_alloc_hsw_probe();
+                if (!rdt_options[RDT_FLAG_L3_CAT].force_off)
+                        cache_alloc_hsw_probe();
                 break;
         }
 }