hvm: Align periodic vpts.

Aligned periodic vpts can improve the HVM guest power consumption a
lot, especially while the guest using high HZ such as 1000HZ.

Signed-off-by: Wei Gang <gang.wei@intel.com>

tools/python/xen/xend/XendConfig.py

@@ -158,6 +158,7 @@ XENAPI_PLATFORM_CFG_TYPES = {
     'vncdisplay': int,
     'vnclisten': str,
     'timer_mode': int,
+    'vpt_align': int,
     'viridian': int,
     'vncpasswd': str,
     'vncunused': int,
@@ -459,6 +460,8 @@ class XendConfig(dict):
                 self['platform']['rtc_timeoffset'] = 0
             if 'hpet' not in self['platform']:
                 self['platform']['hpet'] = 0
+            if 'vpt_align' not in self['platform']:
+                self['platform']['vpt_align'] = 1
             if 'loader' not in self['platform']:
                 # Old configs may have hvmloader set as PV_kernel param
                 if self.has_key('PV_kernel') and self['PV_kernel'] != '':

tools/python/xen/xend/XendConstants.py

@@ -50,6 +50,7 @@ HVM_PARAM_VIRIDIAN     = 9 # x86
 HVM_PARAM_TIMER_MODE   = 10
 HVM_PARAM_HPET_ENABLED = 11
 HVM_PARAM_ACPI_S_STATE = 14
+HVM_PARAM_VPT_ALIGN    = 16
 
 restart_modes = [
     "restart",

tools/python/xen/xend/XendDomainInfo.py

@@ -2237,6 +2237,12 @@ class XendDomainInfo:
             xc.hvm_set_param(self.domid, HVM_PARAM_HPET_ENABLED,
                              long(hpet))
 
+        # Optionally enable periodic vpt aligning
+        vpt_align = self.info["platform"].get("vpt_align")
+        if hvm and vpt_align is not None:
+            xc.hvm_set_param(self.domid, HVM_PARAM_VPT_ALIGN,
+                             long(vpt_align))
+
         # Set maximum number of vcpus in domain
         xc.domain_max_vcpus(self.domid, int(self.info['VCPUs_max']))
 

tools/python/xen/xm/create.py

@@ -219,6 +219,10 @@ 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('vpt_align', val='VPT_ALIGN',
+          fn=set_int, default=1,
+          use="Enable aligning all periodic vpt to reduce timer interrupts.")
+
 gopts.var('viridian', val='VIRIDIAN',
           fn=set_int, default=0,
           use="""Expose Viridian interface to x86 HVM guest?
@@ -891,7 +895,8 @@ def configure_hvm(config_image, vals):
              'sdl', 'display', 'xauthority', 'rtc_timeoffset', 'monitor',
              'acpi', 'apic', 'usb', 'usbdevice', 'keymap', 'pci', 'hpet',
              'guest_os_type', 'hap', 'opengl', 'cpuid', 'cpuid_check',
-             'viridian', 'xen_extended_power_mgmt', 'pci_msitranslate' ]
+             'viridian', 'xen_extended_power_mgmt', 'pci_msitranslate',
+             'vpt_align' ]
 
     for a in args:
         if a in vals.__dict__ and vals.__dict__[a] is not None:

tools/python/xen/xm/xenapi_create.py

@@ -1037,6 +1037,7 @@ class sxp2xml:
             'usbdevice',
             'hpet',
             'timer_mode',
+            'vpt_align',
             'viridian',
             'vhpt',
             'guest_os_type',