x86: add platform hypercall to retrieve pCPU-s' family, model, and stepping

With the recent hotplug changes to the Xen part of the microcode
loading, this allows the kernel driver to avoid unnecessary calls into
the hypervisor during pCPU hot-enabling: Knowing that the hypervisor
retains the data for already booted CPUs, only data for CPUs with a
different signature needs to be passed down. Since the microcode
loading code can be pretty verbose, avoiding to invoke it can make the
log much easier to look at in case of problems.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- 2011-11-23.orig/xen/arch/x86/platform_hypercall.c	2011-12-01 12:06:55.000000000 +0100
+++ 2011-11-23/xen/arch/x86/platform_hypercall.c	2011-12-09 17:39:04.000000000 +0100
@@ -469,6 +469,42 @@ ret_t do_platform_op(XEN_GUEST_HANDLE(xe
     }
     break;
 
+    case XENPF_get_cpu_version:
+    {
+        struct xenpf_pcpu_version *ver = &op->u.pcpu_version;
+
+        if ( !get_cpu_maps() )
+        {
+            ret = -EBUSY;
+            break;
+        }
+
+        if ( (ver->xen_cpuid >= nr_cpu_ids) || !cpu_online(ver->xen_cpuid) )
+        {
+            memset(ver->vendor_id, 0, sizeof(ver->vendor_id));
+            ver->family = 0;
+            ver->model = 0;
+            ver->stepping = 0;
+        }
+        else
+        {
+            const struct cpuinfo_x86 *c = &cpu_data[ver->xen_cpuid];
+
+            memcpy(ver->vendor_id, c->x86_vendor_id, sizeof(ver->vendor_id));
+            ver->family = c->x86;
+            ver->model = c->x86_model;
+            ver->stepping = c->x86_mask;
+        }
+
+        ver->max_present = cpumask_last(&cpu_present_map);
+
+        put_cpu_maps();
+
+        if ( copy_field_to_guest(u_xenpf_op, op, u.pcpu_version) )
+            ret = -EFAULT;
+    }
+    break;
+
     case XENPF_cpu_online:
     {
         int cpu = op->u.cpu_ol.cpuid;
--- 2011-11-23.orig/xen/arch/x86/x86_64/platform_hypercall.c	2011-12-09 17:40:49.000000000 +0100
+++ 2011-11-23/xen/arch/x86/x86_64/platform_hypercall.c	2011-12-01 16:04:28.000000000 +0100
@@ -3,7 +3,7 @@
  */
 
 #include <xen/config.h>
-#include <xen/types.h>
+#include <xen/lib.h>
 #include <compat/platform.h>
 
 DEFINE_XEN_GUEST_HANDLE(compat_platform_op_t);
@@ -26,8 +26,13 @@ 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_pcpuinfo compat_pf_pcpuinfo
-#define xenpf_pcpuinfo_t compat_pf_pcpuinfo_t
+#define xen_pf_pcpuinfo xenpf_pcpuinfo
+CHECK_pf_pcpuinfo;
+#undef xen_pf_pcpuinfo
+
+#define xen_pf_pcpu_version xenpf_pcpu_version
+CHECK_pf_pcpu_version;
+#undef xen_pf_pcpu_version
 
 #define xenpf_enter_acpi_sleep compat_pf_enter_acpi_sleep
 
--- 2011-11-23.orig/xen/include/public/platform.h	2011-12-09 17:40:49.000000000 +0100
+++ 2011-11-23/xen/include/public/platform.h	2011-12-09 17:39:17.000000000 +0100
@@ -449,6 +449,21 @@ struct xenpf_pcpuinfo {
 typedef struct xenpf_pcpuinfo xenpf_pcpuinfo_t;
 DEFINE_XEN_GUEST_HANDLE(xenpf_pcpuinfo_t);
 
+#define XENPF_get_cpu_version 48
+struct xenpf_pcpu_version {
+    /* IN */
+    uint32_t xen_cpuid;
+    /* OUT */
+    /* The maxium cpu_id that is present */
+    uint32_t max_present;
+    char vendor_id[12];
+    uint32_t family;
+    uint32_t model;
+    uint32_t stepping;
+};
+typedef struct xenpf_pcpu_version xenpf_pcpu_version_t;
+DEFINE_XEN_GUEST_HANDLE(xenpf_pcpu_version_t);
+
 #define XENPF_cpu_online    56
 #define XENPF_cpu_offline   57
 struct xenpf_cpu_ol
@@ -492,6 +507,7 @@ struct xen_platform_op {
         struct xenpf_getidletime       getidletime;
         struct xenpf_set_processor_pminfo set_pminfo;
         struct xenpf_pcpuinfo          pcpu_info;
+        struct xenpf_pcpu_version      pcpu_version;
         struct xenpf_cpu_ol            cpu_ol;
         struct xenpf_cpu_hotadd        cpu_add;
         struct xenpf_mem_hotadd        mem_add;
--- 2011-11-23.orig/xen/include/xlat.lst	2011-12-09 17:40:49.000000000 +0100
+++ 2011-11-23/xen/include/xlat.lst	2011-12-01 15:46:31.000000000 +0100
@@ -72,6 +72,17 @@
 ?	physdev_restore_msi		physdev.h
 ?	physdev_set_iopl		physdev.h
 ?	physdev_setup_gsi		physdev.h
+!	pct_register			platform.h
+!	power_register			platform.h
+?	processor_csd			platform.h
+!	processor_cx			platform.h
+!	processor_flags			platform.h
+!	processor_performance		platform.h
+!	processor_power			platform.h
+?	processor_px			platform.h
+!	psd_package			platform.h
+?	xenpf_pcpuinfo			platform.h
+?	xenpf_pcpu_version		platform.h
 !	sched_poll			sched.h
 ?	sched_remote_shutdown		sched.h
 ?	sched_shutdown			sched.h
@@ -84,12 +95,3 @@
 !	vcpu_set_singleshot_timer	vcpu.h
 ?	xenoprof_init			xenoprof.h
 ?	xenoprof_passive		xenoprof.h
-!	power_register			platform.h
-?	processor_csd			platform.h
-!	processor_cx			platform.h
-!	processor_flags			platform.h
-!	processor_power			platform.h
-!	pct_register			platform.h
-?	processor_px			platform.h
-!	psd_package			platform.h
-!	processor_performance		platform.h