x86 hvm: Allow HPET to be configured as a per-domain config option.

A new platform variable 'hpet' is added, which defaults to 0 for new
guests (that is, hpet disabled). Default is off (no hpet) because
hpet is currently less accurate in keeping time than PIT (because no
timer_mode adjustments).

Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Keir Fraser <keir.fraser@citrix.com>

tools/python/xen/xend/XendConfig.py

@@ -127,7 +127,7 @@ LEGACY_CFG_TO_XENAPI_CFG = reverse_dict(XENAPI_CFG_TO_LEGACY_CFG)
 XENAPI_PLATFORM_CFG = [ 'acpi', 'apic', 'boot', 'device_model', 'loader', 'display', 
                         'fda', 'fdb', 'keymap', 'isa', 'localtime', 'monitor', 
                         'nographic', 'pae', 'rtc_timeoffset', 'serial', 'sdl',
-                        'soundhw','stdvga', 'usb', 'usbdevice', 'vnc',
+                        'soundhw','stdvga', 'usb', 'usbdevice', 'hpet', 'vnc',
                         'vncconsole', 'vncdisplay', 'vnclisten', 'timer_mode',
                         'vncpasswd', 'vncunused', 'xauthority', 'pci', 'vhpt',
                         'guest_os_type', 'hap']

tools/python/xen/xend/XendConstants.py

@@ -47,6 +47,7 @@ HVM_PARAM_NVRAM_FD     = 7
 HVM_PARAM_VHPT_SIZE    = 8
 HVM_PARAM_BUFPIOREQ_PFN = 9
 HVM_PARAM_TIMER_MODE   = 10
+HVM_PARAM_HPET_ENABLED = 11
 
 restart_modes = [
     "restart",

tools/python/xen/xend/XendDomainInfo.py

@@ -1692,6 +1692,12 @@ class XendDomainInfo:
             xc.hvm_set_param(self.domid, HVM_PARAM_TIMER_MODE,
                              long(timer_mode))
 
+        # Optionally enable virtual HPET
+        hpet = self.info["platform"].get("hpet")
+        if hvm and hpet is not None:
+            xc.hvm_set_param(self.domid, HVM_PARAM_HPET_ENABLED,
+                             long(hpet))
+
         # Set maximum number of vcpus in domain
         xc.domain_max_vcpus(self.domid, int(self.info['VCPUs_max']))
 

tools/python/xen/xm/create.py

@@ -198,6 +198,10 @@ gopts.var('pae', val='PAE',
           fn=set_int, default=1,
           use="Disable or enable PAE of HVM domain.")
 
+gopts.var('hpet', val='HPET',
+          fn=set_int, default=0,
+          use="Enable virtual high-precision event timer.")
+
 gopts.var('timer_mode', val='TIMER_MODE',
           fn=set_int, default=0,
           use="""Timer mode (0=delay virtual time when ticks are missed;
@@ -740,7 +744,7 @@ def configure_hvm(config_image, vals):
              'localtime', 'serial', 'stdvga', 'isa', 'nographic', 'soundhw',
              'vnc', 'vncdisplay', 'vncunused', 'vncconsole', 'vnclisten',
              'sdl', 'display', 'xauthority', 'rtc_timeoffset', 'monitor',
-             'acpi', 'apic', 'usb', 'usbdevice', 'keymap', 'pci',
+             'acpi', 'apic', 'usb', 'usbdevice', 'keymap', 'pci', 'hpet',
              'guest_os_type', 'hap']
 
     for a in args:

tools/python/xen/xm/xenapi_create.py

@@ -818,7 +818,8 @@ class sxp2xml:
 
 
     def extract_platform(self, image, document):
-        platform_keys = ['acpi', 'apic', 'pae', 'vhpt', 'timer_mode', 'hap']
+        platform_keys = ['acpi', 'apic', 'pae', 'vhpt', 'timer_mode',
+                         'hap', 'hpet']
 
         def extract_platform_key(key):
             platform = document.createElement("platform")