[PATCH v2] x86/irq: hide HYP in /proc/interrupts when not on Xen/Hyper-V

[Vitaly Kuznetsov <vkuznets@redhat.com>]

Hypervisor callback interrupts are only accounted on Xen/Hyper-V. There is
no point in having always-zero HYP: line on other hypervisors or bare
metal. Print the line only if HYPERVISOR_CALLBACK_VECTOR was allocated.

Reported-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
Changes in v2:
- Check if hypervisor callback vector was allocated instead of checking
  x86_hyper against &x86_hyper_ms_hyperv/&x86_hyper_xen. [Ingo Molnar]
---
 arch/x86/kernel/irq.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index 88b36648..5b53747 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -139,10 +139,13 @@ int arch_show_interrupts(struct seq_file *p, int prec)
 	seq_puts(p, "  Machine check polls\n");
 #endif
 #if IS_ENABLED(CONFIG_HYPERV) || defined(CONFIG_XEN)
-	seq_printf(p, "%*s: ", prec, "HYP");
-	for_each_online_cpu(j)
-		seq_printf(p, "%10u ", irq_stats(j)->irq_hv_callback_count);
-	seq_puts(p, "  Hypervisor callback interrupts\n");
+	if (test_bit(HYPERVISOR_CALLBACK_VECTOR, used_vectors)) {
+		seq_printf(p, "%*s: ", prec, "HYP");
+		for_each_online_cpu(j)
+			seq_printf(p, "%10u ",
+				   irq_stats(j)->irq_hv_callback_count);
+		seq_puts(p, "  Hypervisor callback interrupts\n");
+	}
 #endif
 	seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
 #if defined(CONFIG_X86_IO_APIC)
-- 
2.4.3