[PATCH] x86: add hypercall to query current underlying pCPU's frequency

["Jan Beulich" <jbeulich@novell.com>]

Signed-off-by: Jan Beulich <jbeulich@novell.com>

Index: 2008-09-19/xen/arch/x86/platform_hypercall.c
===================================================================
--- 2008-09-19.orig/xen/arch/x86/platform_hypercall.c	2008-09-19 14:12:02.000000000 +0200
+++ 2008-09-19/xen/arch/x86/platform_hypercall.c	2008-09-19 14:12:56.000000000 +0200
@@ -21,7 +21,7 @@
 #include <xen/acpi.h>
 #include <asm/current.h>
 #include <public/platform.h>
-#include <acpi/cpufreq/processor_perf.h>
+#include <acpi/cpufreq/cpufreq.h>
 #include <asm/edd.h>
 #include <asm/mtrr.h>
 #include "cpu/mtrr/mtrr.h"
@@ -55,6 +55,7 @@ static long cpu_frequency_change_helper(
 ret_t do_platform_op(XEN_GUEST_HANDLE(xen_platform_op_t) u_xenpf_op)
 {
     ret_t ret = 0;
+    struct vcpu *v;
     struct xen_platform_op curop, *op = &curop;
 
     if ( !IS_PRIV(current->domain) )
@@ -312,7 +313,6 @@ ret_t do_platform_op(XEN_GUEST_HANDLE(xe
     {
         uint32_t cpu;
         uint64_t idletime, now = NOW();
-        struct vcpu *v;
         struct xenctl_cpumap ctlmap;
         cpumask_t cpumap;
         XEN_GUEST_HANDLE(uint8) cpumap_bitmap;
@@ -482,6 +482,20 @@ ret_t do_platform_op(XEN_GUEST_HANDLE(xe
             break;
         }
         break;
+
+    case XENPF_get_cpu_freq:
+        if ( op->u.get_cpu_freq.vcpu >= MAX_VIRT_CPUS ||
+             !(v = current->domain->vcpu[op->u.get_cpu_freq.vcpu]) )
+        {
+            ret = -EINVAL;
+            break;
+        }
+
+        op->u.get_cpu_freq.freq = cpufreq_cpu_policy[v->processor] ?
+            cpufreq_cpu_policy[v->processor]->cur : 0;
+        if ( copy_field_to_guest(u_xenpf_op, op, u.get_cpu_freq.freq) )
+            ret = -EFAULT;
+        break;
  
     default:
         ret = -ENOSYS;
Index: 2008-09-19/xen/arch/x86/x86_64/platform_hypercall.c
===================================================================
--- 2008-09-19.orig/xen/arch/x86/x86_64/platform_hypercall.c	2008-09-19 14:12:02.000000000 +0200
+++ 2008-09-19/xen/arch/x86/x86_64/platform_hypercall.c	2008-09-19 13:59:35.000000000 +0200
@@ -21,6 +21,8 @@ DEFINE_XEN_GUEST_HANDLE(compat_platform_
 #define xen_processor_power_t   compat_processor_power_t
 #define set_cx_pminfo           compat_set_cx_pminfo
 
+#define xenpf_get_cpu_freq      compat_pf_get_cpu_freq
+
 #define xenpf_enter_acpi_sleep compat_pf_enter_acpi_sleep
 
 #define COMPAT
Index: 2008-09-19/xen/include/public/platform.h
===================================================================
--- 2008-09-19.orig/xen/include/public/platform.h	2008-09-19 14:12:02.000000000 +0200
+++ 2008-09-19/xen/include/public/platform.h	2008-09-19 13:59:35.000000000 +0200
@@ -312,6 +312,16 @@ struct xenpf_set_processor_pminfo {
 typedef struct xenpf_set_processor_pminfo xenpf_set_processor_pminfo_t;
 DEFINE_XEN_GUEST_HANDLE(xenpf_set_processor_pminfo_t);
 
+#define XENPF_get_cpu_freq        55
+struct xenpf_get_cpu_freq {
+    /* IN variables */
+    uint32_t vcpu;
+    /* OUT variables */
+    uint32_t freq; /* in kHz */
+};
+typedef struct xenpf_get_cpu_freq xenpf_get_cpu_freq_t;
+DEFINE_XEN_GUEST_HANDLE(xenpf_get_cpu_freq_t);
+
 struct xen_platform_op {
     uint32_t cmd;
     uint32_t interface_version; /* XENPF_INTERFACE_VERSION */
@@ -327,6 +337,7 @@ struct xen_platform_op {
         struct xenpf_change_freq       change_freq;
         struct xenpf_getidletime       getidletime;
         struct xenpf_set_processor_pminfo set_pminfo;
+        struct xenpf_get_cpu_freq      get_cpu_freq;
         uint8_t                        pad[128];
     } u;
 };