[PATCH v4 13/15] tools/xenpm: fix unnecessary scaling_available_frequencies in CPPC mode

[Penny Zheng <Penny.Zheng@xxxxxxx>]

In `xenpm get-cpufreq-para <cpuid>`, para scaling_available_frequencies
only has meaningful value when cpufreq driver in legacy P-states mode.

So we drop the "has_num" condition check, and mirror the ->gov_num check for
both ->freq_num and ->cpu_num in xc_get_cpufreq_para().
In get_cpufreq_para(), add "freq_num" check to avoid copying data to
op->u.get_para.scaling_available_frequencies in CPPC mode.

Signed-off-by: Penny Zheng <Penny.Zheng@xxxxxxx>
---
v3 -> v4:
- drop the "has_num" condition check
---
 tools/libs/ctrl/xc_pm.c   | 45 +++++++++++++++++++++------------------
 xen/drivers/acpi/pmstat.c | 11 ++++++----
 2 files changed, 31 insertions(+), 25 deletions(-)

diff --git a/tools/libs/ctrl/xc_pm.c b/tools/libs/ctrl/xc_pm.c
index ff7b5ada05..2089aa41b3 100644
--- a/tools/libs/ctrl/xc_pm.c
+++ b/tools/libs/ctrl/xc_pm.c
@@ -212,34 +212,39 @@ int xc_get_cpufreq_para(xc_interface *xch, int cpuid,
     DECLARE_NAMED_HYPERCALL_BOUNCE(scaling_available_governors,
                         user_para->scaling_available_governors,
                         user_para->gov_num * CPUFREQ_NAME_LEN * sizeof(char), 
XC_HYPERCALL_BUFFER_BOUNCE_BOTH);
-    bool has_num = user_para->cpu_num && user_para->freq_num;
 
-    if ( has_num )
+    if ( (user_para->cpu_num && !user_para->affected_cpus) ||
+         (user_para->freq_num && !user_para->scaling_available_frequencies) ||
+         (user_para->gov_num && !user_para->scaling_available_governors) )
+    {
+        errno = EINVAL;
+        return -1;
+    }
+    if ( user_para->cpu_num )
     {
-        if ( (!user_para->affected_cpus)                    ||
-             (!user_para->scaling_available_frequencies)    ||
-             (user_para->gov_num && !user_para->scaling_available_governors) )
-        {
-            errno = EINVAL;
-            return -1;
-        }
         ret = xc_hypercall_bounce_pre(xch, affected_cpus);
         if ( ret )
             return ret;
+    }
+    if ( user_para->freq_num )
+    {
         ret = xc_hypercall_bounce_pre(xch, scaling_available_frequencies);
         if ( ret )
             goto unlock_2;
-        if ( user_para->gov_num )
-            ret = xc_hypercall_bounce_pre(xch, scaling_available_governors);
-        if ( ret )
-            goto unlock_3;
+    }
+    if ( user_para->gov_num )
+        ret = xc_hypercall_bounce_pre(xch, scaling_available_governors);
+    if ( ret )
+        goto unlock_3;
 
+    if ( user_para->cpu_num )
         set_xen_guest_handle(sys_para->affected_cpus, affected_cpus);
-        set_xen_guest_handle(sys_para->scaling_available_frequencies, 
scaling_available_frequencies);
-        if ( user_para->gov_num )
-            set_xen_guest_handle(sys_para->scaling_available_governors,
-                                 scaling_available_governors);
-    }
+    if ( user_para->freq_num )
+        set_xen_guest_handle(sys_para->scaling_available_frequencies,
+                             scaling_available_frequencies);
+    if ( user_para->gov_num )
+        set_xen_guest_handle(sys_para->scaling_available_governors,
+                             scaling_available_governors);
 
     sysctl.cmd = XEN_SYSCTL_pm_op;
     sysctl.u.pm_op.cmd = GET_CPUFREQ_PARA;
@@ -258,9 +263,7 @@ int xc_get_cpufreq_para(xc_interface *xch, int cpuid,
             user_para->gov_num  = sys_para->gov_num;
         }
 
-        if ( has_num )
-            goto unlock_4;
-        return ret;
+        goto unlock_4;
     }
     else
     {
diff --git a/xen/drivers/acpi/pmstat.c b/xen/drivers/acpi/pmstat.c
index 0e90ffcc19..83cfef398e 100644
--- a/xen/drivers/acpi/pmstat.c
+++ b/xen/drivers/acpi/pmstat.c
@@ -228,10 +228,13 @@ static int get_cpufreq_para(struct xen_sysctl_pm_op *op)
     ret = copy_to_guest(op->u.get_para.affected_cpus,
                         data, op->u.get_para.cpu_num);
 
-    for ( i = 0; i < op->u.get_para.freq_num; i++ )
-        data[i] = pmpt->perf.states[i].core_frequency * 1000;
-    ret += copy_to_guest(op->u.get_para.scaling_available_frequencies,
-                         data, op->u.get_para.freq_num);
+    if ( op->u.get_para.freq_num )
+    {
+        for ( i = 0; i < op->u.get_para.freq_num; i++ )
+            data[i] = pmpt->perf.states[i].core_frequency * 1000;
+        ret += copy_to_guest(op->u.get_para.scaling_available_frequencies,
+                             data, op->u.get_para.freq_num);
+    }
 
     xfree(data);
     if ( ret )
-- 
2.34.1