x86, hvm: Hyper-V guest interface support with small set of enlightenments

A minimal implementation of the Viridian (Hyper-V) guest
interface. The only enlightenments advertised and supported are vAPIC
MSRs and long-spin-wait notifications. The set of enlightenments can
easily be extended in future, as they are found to provide a
performance win, and configured via an extended HVM_PARAM_VIRIDIAN hvm
parameter.

Signed-off-by: Peter Johnston <peter.johnston@citrix.com>
Signed-off-by: Tim Deegan <tim.deegan@citrix.com>
Signed-off-by: Keir Fraser <keir.fraser@citrix.com>

tools/python/xen/xend/XendConfig.py

@@ -155,6 +155,7 @@ XENAPI_PLATFORM_CFG_TYPES = {
     'vncdisplay': int,
     'vnclisten': str,
     'timer_mode': int,
+    'viridian': int,
     'vncpasswd': str,
     'vncunused': int,
     'xauthority': str,
@@ -442,6 +443,8 @@ class XendConfig(dict):
         if self.is_hvm():
             if 'timer_mode' not in self['platform']:
                 self['platform']['timer_mode'] = 1
+            if 'viridian' not in self['platform']:
+                self['platform']['viridian'] = 0
             if 'rtc_timeoffset' not in self['platform']:
                 self['platform']['rtc_timeoffset'] = 0
             if 'hpet' not in self['platform']:

tools/python/xen/xend/XendConstants.py

@@ -43,9 +43,10 @@ HVM_PARAM_STORE_EVTCHN = 2
 HVM_PARAM_PAE_ENABLED  = 4
 HVM_PARAM_IOREQ_PFN    = 5
 HVM_PARAM_BUFIOREQ_PFN = 6
-HVM_PARAM_NVRAM_FD     = 7
-HVM_PARAM_VHPT_SIZE    = 8
-HVM_PARAM_BUFPIOREQ_PFN = 9
+HVM_PARAM_NVRAM_FD     = 7 # ia64
+HVM_PARAM_VHPT_SIZE    = 8 # ia64
+HVM_PARAM_BUFPIOREQ_PFN = 9 # ia64
+HVM_PARAM_VIRIDIAN     = 9 # x86
 HVM_PARAM_TIMER_MODE   = 10
 HVM_PARAM_HPET_ENABLED = 11
 HVM_PARAM_ACPI_S_STATE = 14

tools/python/xen/xend/XendDomainInfo.py

@@ -2078,6 +2078,11 @@ class XendDomainInfo:
             xc.hvm_set_param(self.domid, HVM_PARAM_TIMER_MODE,
                              long(timer_mode))
 
+        # Set Viridian interface configuration of domain
+        viridian = self.info["platform"].get("viridian")
+        if arch.type == "x86" and hvm and viridian is not None:
+            xc.hvm_set_param(self.domid, HVM_PARAM_VIRIDIAN, long(viridian))
+
         # Optionally enable virtual HPET
         hpet = self.info["platform"].get("hpet")
         if hvm and hpet is not None:

tools/python/xen/xm/create.py

@@ -218,6 +218,11 @@ gopts.var('timer_mode', val='TIMER_MODE',
           use="""Timer mode (0=delay virtual time when ticks are missed;
           1=virtual time is always wallclock time.""")
 
+gopts.var('viridian', val='VIRIDIAN',
+          fn=set_int, default=0,
+          use="""Expose Viridian interface to x86 HVM guest?
+          (Default is 0).""")
+
 gopts.var('acpi', val='ACPI',
           fn=set_int, default=1,
           use="Disable or enable ACPI of HVM domain.")
@@ -856,7 +861,8 @@ def configure_hvm(config_image, vals):
              'vnc', 'vncdisplay', 'vncunused', 'vncconsole', 'vnclisten',
              'sdl', 'display', 'xauthority', 'rtc_timeoffset', 'monitor',
              'acpi', 'apic', 'usb', 'usbdevice', 'keymap', 'pci', 'hpet',
-             'guest_os_type', 'hap', 'opengl', 'cpuid', 'cpuid_check']
+             'guest_os_type', 'hap', 'opengl', 'cpuid', 'cpuid_check',
+             'viridian' ]
 
     for a in args:
         if a in vals.__dict__ and vals.__dict__[a] is not None:

tools/python/xen/xm/xenapi_create.py

@@ -969,6 +969,7 @@ class sxp2xml:
             'usbdevice',
             'hpet',
             'timer_mode',
+            'viridian',
             'vhpt',
             'guest_os_type',
             'hap',