1 files changed, 40 insertions, 0 deletions

diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 9340f41ce8d3..4488cf0dd499 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -37,6 +37,7 @@ EXPORT_SYMBOL_GPL(ms_hyperv);
 
 #if IS_ENABLED(CONFIG_HYPERV)
 static void (*vmbus_handler)(void);
+static void (*hv_stimer0_handler)(void);
 static void (*hv_kexec_handler)(void);
 static void (*hv_crash_handler)(struct pt_regs *regs);
 
@@ -69,6 +70,41 @@ void hv_remove_vmbus_irq(void)
 EXPORT_SYMBOL_GPL(hv_setup_vmbus_irq);
 EXPORT_SYMBOL_GPL(hv_remove_vmbus_irq);
 
+/*
+ * Routines to do per-architecture handling of stimer0
+ * interrupts when in Direct Mode
+ */
+
+__visible void __irq_entry hv_stimer0_vector_handler(struct pt_regs *regs)
+{
+        struct pt_regs *old_regs = set_irq_regs(regs);
+
+        entering_irq();
+        inc_irq_stat(hyperv_stimer0_count);
+        if (hv_stimer0_handler)
+                hv_stimer0_handler();
+        ack_APIC_irq();
+
+        exiting_irq();
+        set_irq_regs(old_regs);
+}
+
+int hv_setup_stimer0_irq(int *irq, int *vector, void (*handler)(void))
+{
+        *vector = HYPERV_STIMER0_VECTOR;
+        *irq = 0;   /* Unused on x86/x64 */
+        hv_stimer0_handler = handler;
+        return 0;
+}
+EXPORT_SYMBOL_GPL(hv_setup_stimer0_irq);
+
+void hv_remove_stimer0_irq(int irq)
+{
+        /* We have no way to deallocate the interrupt gate */
+        hv_stimer0_handler = NULL;
+}
+EXPORT_SYMBOL_GPL(hv_remove_stimer0_irq);
+
 void hv_setup_kexec_handler(void (*handler)(void))
 {
         hv_kexec_handler = handler;
@@ -257,6 +293,10 @@ static void __init ms_hyperv_init_platform(void)
                 alloc_intr_gate(HYPERV_REENLIGHTENMENT_VECTOR,
                                 hyperv_reenlightenment_vector);
 
+        /* Setup the IDT for stimer0 */
+        if (ms_hyperv.misc_features & HV_X64_STIMER_DIRECT_MODE_AVAILABLE)
+                alloc_intr_gate(HYPERV_STIMER0_VECTOR,
+                                hv_stimer0_callback_vector);
 #endif
 }