x86/Kconfig: Add new X86_HV_CALLBACK_VECTOR config symbol

Add a special Kconfig symbol X86_HV_CALLBACK_VECTOR so that the guests
using the hypervisor interrupt callback counter can select and thus
enable that counter. Select it when xen or hyperv support is enabled. No
functional changes.

Signed-off-by: Zhao Yakui <[e-mail]>
Signed-off-by: Borislav Petkov <[e-mail]>
Reviewed-by: Borislav Petkov <[e-mail]>
Reviewed-by: Thomas Gleixner <[e-mail]>
Cc: Boris Ostrovsky <[e-mail]>
Cc: Frederic Weisbecker <[e-mail]>
Cc: Haiyang Zhang <[e-mail]>
Cc: "H. Peter Anvin" <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Juergen Gross <[e-mail]>
Cc: "K. Y. Srinivasan" <[e-mail]>
Cc: [e-mail]
Cc: Nicolai Stange <[e-mail]>
Cc: Paolo Bonzini <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Sasha Levin <[e-mail]>
Cc: Stefano Stabellini <[e-mail]>
Cc: Stephen Hemminger <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: x86-ml <[e-mail]>
Cc: [e-mail]
Link: https://lkml.kernel.org/r/[e-mail]

arch/x86/Kconfig

···
 
 	  If you are unsure how to answer this question, answer Y.
 
+config X86_HV_CALLBACK_VECTOR
+	def_bool n
+
 source "arch/x86/xen/Kconfig"
 
 config KVM_GUEST

arch/x86/include/asm/hardirq.h

···
 #ifdef CONFIG_X86_MCE_AMD
 	unsigned int irq_deferred_error_count;
 #endif
-#if IS_ENABLED(CONFIG_HYPERV) || defined(CONFIG_XEN)
+#ifdef CONFIG_X86_HV_CALLBACK_VECTOR
 	unsigned int irq_hv_callback_count;
 #endif
 #if IS_ENABLED(CONFIG_HYPERV)

arch/x86/kernel/irq.c

···
 		seq_printf(p, "%10u ", per_cpu(mce_poll_count, j));
 	seq_puts(p, "  Machine check polls\n");
 #endif
-#if IS_ENABLED(CONFIG_HYPERV) || defined(CONFIG_XEN)
+#ifdef CONFIG_X86_HV_CALLBACK_VECTOR
 	if (test_bit(HYPERVISOR_CALLBACK_VECTOR, system_vectors)) {
 		seq_printf(p, "%*s: ", prec, "HYP");
 		for_each_online_cpu(j)

arch/x86/xen/Kconfig

···
 	bool "Xen guest support"
 	depends on PARAVIRT
 	select PARAVIRT_CLOCK
+	select X86_HV_CALLBACK_VECTOR
 	depends on X86_64 || (X86_32 && X86_PAE)
 	depends on X86_LOCAL_APIC && X86_TSC
 	help

drivers/hv/Kconfig

···
 	tristate "Microsoft Hyper-V client drivers"
 	depends on X86 && ACPI && X86_LOCAL_APIC && HYPERVISOR_GUEST
 	select PARAVIRT
+	select X86_HV_CALLBACK_VECTOR
 	help
 	  Select this option to run Linux as a Hyper-V client operating
 	  system.