Introduce CONFIG_XEN_PVHVM compile option

This patch introduce a CONFIG_XEN_PVHVM compile time option to
enable/disable Xen PV on HVM support.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

arch/x86/kernel/cpu/hypervisor.c

@@ -34,7 +34,7 @@ static const __initconst struct hypervisor_x86 * const hypervisors[] =
 {
 	&x86_hyper_vmware,
 	&x86_hyper_ms_hyperv,
-#ifdef CONFIG_XEN
+#ifdef CONFIG_XEN_PVHVM
 	&x86_hyper_xen_hvm,
 #endif
 };

arch/x86/xen/Kconfig

@@ -13,6 +13,11 @@ config XEN
 	  kernel to boot in a paravirtualized environment under the
 	  Xen hypervisor.
 
+config XEN_PVHVM
+	def_bool y
+	depends on XEN
+	depends on X86_LOCAL_APIC
+
 config XEN_MAX_DOMAIN_MEMORY
        int "Maximum allowed size of a domain in gigabytes"
        default 8 if X86_32

arch/x86/xen/enlighten.c

@@ -1282,6 +1282,7 @@ void xen_hvm_init_shared_info(void)
 	}
 }
 
+#ifdef CONFIG_XEN_PVHVM
 static int __cpuinit xen_hvm_cpu_notify(struct notifier_block *self,
 				    unsigned long action, void *hcpu)
 {
@@ -1338,3 +1339,4 @@ const __refconst struct hypervisor_x86 x86_hyper_xen_hvm = {
 	.init_platform		= xen_hvm_guest_init,
 };
 EXPORT_SYMBOL(x86_hyper_xen_hvm);
+#endif

arch/x86/xen/mmu.c

@@ -1942,6 +1942,7 @@ void __init xen_init_mmu_ops(void)
 	pv_mmu_ops = xen_mmu_ops;
 }
 
+#ifdef CONFIG_XEN_PVHVM
 static void xen_hvm_exit_mmap(struct mm_struct *mm)
 {
 	struct xen_hvm_pagetable_dying a;
@@ -1973,6 +1974,7 @@ void __init xen_hvm_init_mmu_ops(void)
 	if (is_pagetable_dying_supported())
 		pv_mmu_ops.exit_mmap = xen_hvm_exit_mmap;
 }
+#endif
 
 #ifdef CONFIG_XEN_DEBUG_FS
 

arch/x86/xen/platform-pci-unplug.c

@@ -32,6 +32,7 @@
 /* store the value of xen_emul_unplug after the unplug is done */
 int xen_platform_pci_unplug;
 EXPORT_SYMBOL_GPL(xen_platform_pci_unplug);
+#ifdef CONFIG_XEN_PVHVM
 static int xen_emul_unplug;
 
 static int __init check_platform_magic(void)
@@ -133,3 +134,4 @@ static int __init parse_xen_emul_unplug(char *arg)
 	return 0;
 }
 early_param("xen_emul_unplug", parse_xen_emul_unplug);
+#endif

arch/x86/xen/time.c

@@ -516,6 +516,7 @@ __init void xen_init_time_ops(void)
 	x86_platform.set_wallclock = xen_set_wallclock;
 }
 
+#ifdef CONFIG_XEN_PVHVM
 static void xen_hvm_setup_cpu_clockevents(void)
 {
 	int cpu = smp_processor_id();
@@ -544,4 +545,4 @@ __init void xen_hvm_init_time_ops(void)
 	x86_platform.get_wallclock = xen_get_wallclock;
 	x86_platform.set_wallclock = xen_set_wallclock;
 }
-
+#endif

drivers/xen/Kconfig

@@ -64,7 +64,7 @@ config XEN_SYS_HYPERVISOR
 
 config XEN_PLATFORM_PCI
 	tristate "xen platform pci device driver"
-	depends on XEN
+	depends on XEN_PVHVM
 	default m
 	help
 	  Driver for the Xen PCI Platform device: it is responsible for

drivers/xen/events.c

@@ -973,6 +973,7 @@ int xen_set_callback_via(uint64_t via)
 }
 EXPORT_SYMBOL_GPL(xen_set_callback_via);
 
+#ifdef CONFIG_XEN_PVHVM
 /* Vector callbacks are better than PCI interrupts to receive event
  * channel notifications because we can receive vector callbacks on any
  * vcpu and we don't need PCI support or APIC interactions. */
@@ -996,6 +997,9 @@ void xen_callback_vector(void)
 			alloc_intr_gate(XEN_HVM_EVTCHN_CALLBACK, xen_hvm_callback_vector);
 	}
 }
+#else
+void xen_callback_vector(void) {}
+#endif
 
 void __init xen_init_IRQ(void)
 {