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[PATCH v7 09/15] cpufreq: Export HWP parameters to userspace as CPPC



Extend xen_get_cpufreq_para to return hwp parameters.  HWP is an
implementation of ACPI CPPC (Collaborative Processor Performance
Control).  Use the CPPC name since that might be useful in the future
for AMD P-state.

We need the features bitmask to indicate fields supported by the actual
hardware - this only applies to activity window for the time being.

The HWP most_efficient is mapped to CPPC lowest_nonlinear, and guaranteed is
mapped to nominal.  CPPC has a guaranteed that is optional while nominal
is required.  ACPI spec says "If this register is not implemented, OSPM
assumes guaranteed performance is always equal to nominal performance."

Signed-off-by: Jason Andryuk <jandryuk@xxxxxxxxx>
Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
---
v2:
Style fixes
Don't bump XEN_SYSCTL_INTERFACE_VERSION
Drop cpufreq.h comment divider
Expand xen_hwp_para comment
Add HWP activity window mantissa/exponent defines
Handle union rename
Add const to get_hwp_para
Remove hw_ prefix from xen_hwp_para members
Use XEN_HWP_GOVERNOR
Use per_cpu for hwp_drv_data

v4:
Fixup for opt_cpufreq_hwp/hdc removal
get_hwp_para() takes cpu as arg
XEN_ prefix HWP_ACT_WINDOW_*
Drop HWP_ACT_WINDOW_EXPONENT_SHIFT - shift MASK
Remove Energy Bias (0-15) EPP fallback
Rename xen_hwp_para to xen_cppc_para
s/hwp/cppc/
Use scaling driver to switch output

v5:
Use XEN_HWP_DRIVER_NAME
Use cpufreq.h for declarations
Fixup some comments
Drop const from unsigned int cpu
Drop some unnecessary { }
Use strncmp
Switch sizeof(char) to sizeof(*scaling_available_governors)
Reindent copy_to_guest call
Add "HWP: " prefix to sysctl comments for cppc->hwp mapping

v6:
Drop commit message uint8_t paragraph
sysctl.h s/They/They're/
Fix indent and add parens for read_scaling_available_governors() args
Add Jan's Ack
---
 xen/arch/x86/acpi/cpufreq/hwp.c    | 23 ++++++++++
 xen/drivers/acpi/pmstat.c          | 74 ++++++++++++++++--------------
 xen/include/acpi/cpufreq/cpufreq.h |  2 +
 xen/include/public/sysctl.h        | 56 ++++++++++++++++++++++
 4 files changed, 121 insertions(+), 34 deletions(-)

diff --git a/xen/arch/x86/acpi/cpufreq/hwp.c b/xen/arch/x86/acpi/cpufreq/hwp.c
index 33039ad39e..2cbfa1ce33 100644
--- a/xen/arch/x86/acpi/cpufreq/hwp.c
+++ b/xen/arch/x86/acpi/cpufreq/hwp.c
@@ -519,6 +519,29 @@ static const struct cpufreq_driver __initconstrel 
hwp_cpufreq_driver =
     .update = hwp_cpufreq_update,
 };
 
+int get_hwp_para(unsigned int cpu,
+                 struct xen_cppc_para *cppc_para)
+{
+    const struct hwp_drv_data *data = per_cpu(hwp_drv_data, cpu);
+
+    if ( data == NULL )
+        return -ENODATA;
+
+    cppc_para->features         =
+        (feature_hwp_activity_window ? XEN_SYSCTL_CPPC_FEAT_ACT_WINDOW : 0);
+    cppc_para->lowest           = data->hw.lowest;
+    cppc_para->lowest_nonlinear = data->hw.most_efficient;
+    cppc_para->nominal          = data->hw.guaranteed;
+    cppc_para->highest          = data->hw.highest;
+    cppc_para->minimum          = data->minimum;
+    cppc_para->maximum          = data->maximum;
+    cppc_para->desired          = data->desired;
+    cppc_para->energy_perf      = data->energy_perf;
+    cppc_para->activity_window  = data->activity_window;
+
+    return 0;
+}
+
 int __init hwp_register_driver(void)
 {
     int ret;
diff --git a/xen/drivers/acpi/pmstat.c b/xen/drivers/acpi/pmstat.c
index d67d99e62f..e4e2df94a7 100644
--- a/xen/drivers/acpi/pmstat.c
+++ b/xen/drivers/acpi/pmstat.c
@@ -251,46 +251,52 @@ static int get_cpufreq_para(struct xen_sysctl_pm_op *op)
     else
         strlcpy(op->u.get_para.scaling_driver, "Unknown", CPUFREQ_NAME_LEN);
 
-    if ( !(scaling_available_governors =
-           xzalloc_array(char, gov_num * CPUFREQ_NAME_LEN)) )
-        return -ENOMEM;
-    if ( (ret = read_scaling_available_governors(scaling_available_governors,
-                gov_num * CPUFREQ_NAME_LEN * sizeof(char))) )
+    if ( !strncmp(op->u.get_para.scaling_driver, XEN_HWP_DRIVER_NAME,
+                      CPUFREQ_NAME_LEN) )
+        ret = get_hwp_para(policy->cpu, &op->u.get_para.u.cppc_para);
+    else
     {
+        if ( !(scaling_available_governors =
+               xzalloc_array(char, gov_num * CPUFREQ_NAME_LEN)) )
+            return -ENOMEM;
+        if ( (ret = read_scaling_available_governors(
+                        scaling_available_governors,
+                        (gov_num * CPUFREQ_NAME_LEN *
+                         sizeof(*scaling_available_governors)))) )
+        {
+            xfree(scaling_available_governors);
+            return ret;
+        }
+        ret = copy_to_guest(op->u.get_para.scaling_available_governors,
+                            scaling_available_governors,
+                            gov_num * CPUFREQ_NAME_LEN);
         xfree(scaling_available_governors);
-        return ret;
-    }
-    ret = copy_to_guest(op->u.get_para.scaling_available_governors,
-                scaling_available_governors, gov_num * CPUFREQ_NAME_LEN);
-    xfree(scaling_available_governors);
-    if ( ret )
-        return ret;
+        if ( ret )
+            return ret;
 
-    op->u.get_para.u.s.scaling_cur_freq = policy->cur;
-    op->u.get_para.u.s.scaling_max_freq = policy->max;
-    op->u.get_para.u.s.scaling_min_freq = policy->min;
+        op->u.get_para.u.s.scaling_cur_freq = policy->cur;
+        op->u.get_para.u.s.scaling_max_freq = policy->max;
+        op->u.get_para.u.s.scaling_min_freq = policy->min;
 
-    if ( policy->governor->name[0] )
-        strlcpy(op->u.get_para.u.s.scaling_governor,
-            policy->governor->name, CPUFREQ_NAME_LEN);
-    else
-        strlcpy(op->u.get_para.u.s.scaling_governor, "Unknown", 
CPUFREQ_NAME_LEN);
+        if ( policy->governor->name[0] )
+            strlcpy(op->u.get_para.u.s.scaling_governor,
+                policy->governor->name, CPUFREQ_NAME_LEN);
+        else
+            strlcpy(op->u.get_para.u.s.scaling_governor, "Unknown",
+                    CPUFREQ_NAME_LEN);
 
-    /* governor specific para */
-    if ( !strncasecmp(op->u.get_para.u.s.scaling_governor,
-                      "userspace", CPUFREQ_NAME_LEN) )
-    {
-        op->u.get_para.u.s.u.userspace.scaling_setspeed = policy->cur;
-    }
+        /* governor specific para */
+        if ( !strncasecmp(op->u.get_para.u.s.scaling_governor,
+                          "userspace", CPUFREQ_NAME_LEN) )
+            op->u.get_para.u.s.u.userspace.scaling_setspeed = policy->cur;
 
-    if ( !strncasecmp(op->u.get_para.u.s.scaling_governor,
-                      "ondemand", CPUFREQ_NAME_LEN) )
-    {
-        ret = get_cpufreq_ondemand_para(
-            &op->u.get_para.u.s.u.ondemand.sampling_rate_max,
-            &op->u.get_para.u.s.u.ondemand.sampling_rate_min,
-            &op->u.get_para.u.s.u.ondemand.sampling_rate,
-            &op->u.get_para.u.s.u.ondemand.up_threshold);
+        if ( !strncasecmp(op->u.get_para.u.s.scaling_governor,
+                          "ondemand", CPUFREQ_NAME_LEN) )
+            ret = get_cpufreq_ondemand_para(
+                &op->u.get_para.u.s.u.ondemand.sampling_rate_max,
+                &op->u.get_para.u.s.u.ondemand.sampling_rate_min,
+                &op->u.get_para.u.s.u.ondemand.sampling_rate,
+                &op->u.get_para.u.s.u.ondemand.up_threshold);
     }
 
     return ret;
diff --git a/xen/include/acpi/cpufreq/cpufreq.h 
b/xen/include/acpi/cpufreq/cpufreq.h
index 6737798e25..f90e9d3a6c 100644
--- a/xen/include/acpi/cpufreq/cpufreq.h
+++ b/xen/include/acpi/cpufreq/cpufreq.h
@@ -255,5 +255,7 @@ void intel_feature_detect(struct cpufreq_policy *policy);
 int hwp_cmdline_parse(const char *s, const char *e);
 int hwp_register_driver(void);
 bool hwp_active(void);
+int get_hwp_para(unsigned int cpu,
+                 struct xen_cppc_para *cppc_para);
 
 #endif /* __XEN_CPUFREQ_PM_H__ */
diff --git a/xen/include/public/sysctl.h b/xen/include/public/sysctl.h
index 5a30b16fcf..cf27f8f2f9 100644
--- a/xen/include/public/sysctl.h
+++ b/xen/include/public/sysctl.h
@@ -296,6 +296,61 @@ struct xen_ondemand {
     uint32_t up_threshold;
 };
 
+struct xen_cppc_para {
+    /* OUT */
+    /* activity_window supported if set */
+#define XEN_SYSCTL_CPPC_FEAT_ACT_WINDOW  (1 << 0)
+    uint32_t features; /* bit flags for features */
+    /*
+     * See Intel SDM: HWP Performance Range and Dynamic Capabilities
+     *
+     * These four are 0-255 hardware-provided values.  They're "continuous,
+     * abstract unit-less, performance" values.  Smaller numbers are slower
+     * and larger ones are faster.
+     */
+    uint32_t lowest;
+    uint32_t lowest_nonlinear; /* HWP: most_efficient */
+    uint32_t nominal; /* HWP: guaranteed */
+    uint32_t highest;
+    /*
+     * See Intel SDM: IA32_HWP_REQUEST MSR (Address: 774H Logical Processor
+     * Scope)
+     *
+     * These are all hints, and the processor may deviate outside of them.
+     * Values below are 0-255.
+     *
+     * minimum and maximum can be set to the above hardware values to constrain
+     * operation.  The full range 0-255 is accepted and will be clipped by
+     * hardware.
+     */
+    uint32_t minimum;
+    uint32_t maximum;
+    /*
+     * An explicit performance hint, disabling hardware selection.
+     * 0 lets the hardware decide.
+     */
+    uint32_t desired;
+    /*
+     * Hint to hardware for energy/performance preference.
+     * 0:   Performance
+     * 128: Balance (Default)
+     * 255: Powersaving
+     */
+    uint32_t energy_perf;
+    /*
+     * Activity Window is a moving history window for the processor's operation
+     * calculations, controlling responsiveness.  Measured in microseconds
+     * encoded as:
+     *
+     * bits 6:0   - 7bit mantissa
+     * bits 9:7   - 3bit base-10 exponent
+     * btis 15:10 - Unused - must be 0
+     */
+#define XEN_CPPC_ACT_WINDOW_MANTISSA_MASK  0x07f
+#define XEN_CPPC_ACT_WINDOW_EXPONENT_MASK  0x380
+    uint32_t activity_window;
+};
+
 #define XEN_HWP_DRIVER_NAME "hwp"
 
 /*
@@ -333,6 +388,7 @@ struct xen_get_cpufreq_para {
                 struct  xen_ondemand ondemand;
             } u;
         } s;
+        struct xen_cppc_para cppc_para;
     } u;
 
     int32_t turbo_enabled;
-- 
2.41.0




 


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