hv: mshv_vtl: Handle unmapping of redirected interrupts

User space requests the tear down of a redirected interrupt using the
APIC ID and the CPU interrupt vector number associated with it.

Traverse the list of redirected interrupt and release the resources of
the IRQ being teared down.

Signed-off-by: Ricardo Neri <[email protected]>
---
Changes since v2:
 * Introduced this patch.

Changes since v1:
 * N/A

Author: ricardon

drivers/hv/mshv_vtl_main.c

@@ -1759,7 +1759,24 @@ static int mshv_vtl_map_redirected_intr(u32 proxy_vector, u32 apic_id)
 
 static int mshv_vtl_unmap_redirected_intr(u32 hw_vector, u32 apic_id)
 {
-	return -ENODEV;
+	struct redirected_intr *rintr;
+
+	if (hw_vector  > 255)
+		return -EINVAL;
+
+	guard(mutex)(&redirected_intr_lock);
+	list_for_each_entry(rintr, &redirected_intr_list, list) {
+		unsigned int vector = irq_cfg(rintr->irq)->vector;
+
+		if (vector == hw_vector && rintr->apic_id == apic_id) {
+			free_irq(rintr->irq, rintr);
+			list_del(&rintr->list);
+			kfree(rintr);
+			return 0;
+		}
+	}
+
+	return -ENOENT;
 }
 
 static long mshv_vtl_ioctl_setup_redirected_intr(void __user *user_arg)