x86, hyperv: Handle Xen emulation of Hyper-V more gracefully
Install the Hyper-V specific interrupt handler only when needed. This would
permit us to get rid of the Xen check. Note that when the vmbus drivers invokes
the call to register its handler, we are sure to be running on Hyper-V.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Link: http://lkml.kernel.org/r/1366299886-6399-1-git-send-email-kys@microsoft.com
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index a7d26d8..8f4be53 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -35,13 +35,6 @@
if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
return false;
- /*
- * Xen emulates Hyper-V to support enlightened Windows.
- * Check to see first if we are on a Xen Hypervisor.
- */
- if (xen_cpuid_base())
- return false;
-
cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
&eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);
@@ -82,12 +75,6 @@
if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)
clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100);
-#if IS_ENABLED(CONFIG_HYPERV)
- /*
- * Setup the IDT for hypervisor callback.
- */
- alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector);
-#endif
}
const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
@@ -103,6 +90,11 @@
void hv_register_vmbus_handler(int irq, irq_handler_t handler)
{
+ /*
+ * Setup the IDT for hypervisor callback.
+ */
+ alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector);
+
vmbus_irq = irq;
vmbus_isr = handler;
}