3 files changed, 47 insertions, 74 deletions

diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index cd9c41938b8a..e98f66f35635 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -2,6 +2,7 @@
 #define _ASM_X86_MSHYPER_H
 
 #include <linux/types.h>
+#include <linux/interrupt.h>
 #include <asm/hyperv.h>
 
 struct ms_hyperv_info {
@@ -16,6 +17,7 @@ void hyperv_callback_vector(void);
 #define trace_hyperv_callback_vector hyperv_callback_vector
 #endif
 void hyperv_vector_handler(struct pt_regs *regs);
-void hv_register_vmbus_handler(int irq, irq_handler_t handler);
+int hv_setup_vmbus_irq(int irq, irq_handler_t handler, void *dev_id);
+void hv_remove_vmbus_irq(int irq, void *dev_id);
 
 #endif
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 9f7ca266864a..1bd316cd32c8 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -17,6 +17,7 @@
 #include <linux/hardirq.h>
 #include <linux/efi.h>
 #include <linux/interrupt.h>
+#include <linux/irq.h>
 #include <asm/processor.h>
 #include <asm/hypervisor.h>
 #include <asm/hyperv.h>
@@ -30,6 +31,45 @@
 struct ms_hyperv_info ms_hyperv;
 EXPORT_SYMBOL_GPL(ms_hyperv);
 
+#ifdef CONFIG_HYPERV
+static irq_handler_t *vmbus_handler;
+
+void hyperv_vector_handler(struct pt_regs *regs)
+{
+        struct pt_regs *old_regs = set_irq_regs(regs);
+
+        irq_enter();
+        exit_idle();
+
+        inc_irq_stat(irq_hv_callback_count);
+        if (vmbus_handler)
+                vmbus_handler();
+
+        irq_exit();
+        set_irq_regs(old_regs);
+}
+
+int hv_setup_vmbus_irq(int irq, irq_handler_t *handler, void *dev_id)
+{
+        vmbus_handler = handler;
+        /*
+         * Setup the IDT for hypervisor callback. Prevent reallocation
+         * at module reload.
+         */
+        if (!test_bit(HYPERVISOR_CALLBACK_VECTOR, used_vectors))
+                alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR,
+                                hyperv_callback_vector);
+}
+
+void hv_remove_vmbus_irq(unsigned int irq, void *dev_id)
+{
+        /* We have no way to deallocate the interrupt gate */
+        vmbus_handler = NULL;
+}
+EXPORT_SYMBOL_GPL(hv_setup_vmbus_irq);
+EXPORT_SYMBOL_GPL(hv_remove_vmbus_irq);
+#endif
+
 static uint32_t  __init ms_hyperv_platform(void)
 {
         u32 eax;
@@ -113,41 +153,3 @@ const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
         .init_platform          = ms_hyperv_init_platform,
 };
 EXPORT_SYMBOL(x86_hyper_ms_hyperv);
-
-#if IS_ENABLED(CONFIG_HYPERV)
-static int vmbus_irq = -1;
-static irq_handler_t vmbus_isr;
-
-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;
-}
-
-void hyperv_vector_handler(struct pt_regs *regs)
-{
-        struct pt_regs *old_regs = set_irq_regs(regs);
-        struct irq_desc *desc;
-
-        irq_enter();
-        exit_idle();
-
-        desc = irq_to_desc(vmbus_irq);
-
-        if (desc)
-                generic_handle_irq_desc(vmbus_irq, desc);
-
-        irq_exit();
-        set_irq_regs(old_regs);
-}
-#else
-void hv_register_vmbus_handler(int irq, irq_handler_t handler)
-{
-}
-#endif
-EXPORT_SYMBOL_GPL(hv_register_vmbus_handler);
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 077bb1bdac34..5a6909fff1c1 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -25,7 +25,6 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/device.h>
-#include <linux/irq.h>
 #include <linux/interrupt.h>
 #include <linux/sysctl.h>
 #include <linux/slab.h>
@@ -558,9 +557,6 @@ static struct bus_type  hv_bus = {
         .dev_groups =           vmbus_groups,
 };
 
-static const char *driver_name = "hyperv";
-
-
 struct onmessage_work_context {
         struct work_struct work;
         struct hv_message msg;
@@ -677,19 +673,6 @@ static irqreturn_t vmbus_isr(int irq, void *dev_id)
 }
 
 /*
- * vmbus interrupt flow handler:
- * vmbus interrupts can concurrently occur on multiple CPUs and
- * can be handled concurrently.
- */
-
-static void vmbus_flow_handler(unsigned int irq, struct irq_desc *desc)
-{
-        kstat_incr_irqs_this_cpu(irq, desc);
-
-        desc->action->handler(irq, desc->action->dev_id);
-}
-
-/*
  * vmbus_bus_init -Main vmbus driver initialization routine.
  *
  * Here, we
@@ -715,26 +698,13 @@ static int vmbus_bus_init(int irq)
         if (ret)
                 goto err_cleanup;
 
-        ret = request_irq(irq, vmbus_isr, 0, driver_name, hv_acpi_dev);
+        ret = hv_setup_vmbus_irq(irq, vmbus_isr, hv_acpi_dev);
 
         if (ret != 0) {
-                pr_err("Unable to request IRQ %d\n",
-                           irq);
+                pr_err("Unable to request IRQ %d\n", irq);
                 goto err_unregister;
         }
 
-        /*
-         * Vmbus interrupts can be handled concurrently on
-         * different CPUs. Establish an appropriate interrupt flow
-         * handler that can support this model.
-         */
-        irq_set_handler(irq, vmbus_flow_handler);
-
-        /*
-         * Register our interrupt handler.
-         */
-        hv_register_vmbus_handler(irq, vmbus_isr);
-
         ret = hv_synic_alloc();
         if (ret)
                 goto err_alloc;
@@ -753,7 +723,7 @@ static int vmbus_bus_init(int irq)
 
 err_alloc:
         hv_synic_free();
-        free_irq(irq, hv_acpi_dev);
+        hv_remove_vmbus_irq(irq, hv_acpi_dev);
 
 err_unregister:
         bus_unregister(&hv_bus);
@@ -978,8 +948,7 @@ cleanup:
 
 static void __exit vmbus_exit(void)
 {
-
-        free_irq(irq, hv_acpi_dev);
+        hv_remove_vmbus_irq(irq, hv_acpi_dev);
         vmbus_free_channels();
         bus_unregister(&hv_bus);
         hv_cleanup();