3 files changed, 66 insertions, 31 deletions

diff --git a/arch/x86/include/asm/uintr.h b/arch/x86/include/asm/uintr.h
index 64113ef523ca..a8bb151e4c8f 100644
--- a/arch/x86/include/asm/uintr.h
+++ b/arch/x86/include/asm/uintr.h
@@ -61,7 +61,7 @@ void uintr_free(struct task_struct *task);
 void switch_uintr_prepare(struct task_struct *prev);
 void switch_uintr_return(void);
 
-int uintr_receiver_wait(void);
+int uintr_receiver_wait(ktime_t *expires);
 void uintr_wake_up_process(void);
 
 #else /* !CONFIG_X86_USER_INTERRUPTS */
diff --git a/arch/x86/kernel/uintr_core.c b/arch/x86/kernel/uintr_core.c
index dca8819ac3fd..4856a68f7743 100644
--- a/arch/x86/kernel/uintr_core.c
+++ b/arch/x86/kernel/uintr_core.c
@@ -7,6 +7,7 @@
  */
 #define pr_fmt(fmt)    "uintr: " fmt
 
+#include <linux/hrtimer.h>
 #include <linux/refcount.h>
 #include <linux/sched.h>
 #include <linux/sched/task.h>
@@ -489,25 +490,70 @@ int do_uintr_register_sender(struct uintr_receiver_info *r_info,
 	return 0;
 }
 
-int uintr_receiver_wait(void)
+/* Called when task is unregistering/exiting or timer expired */
+static void uintr_remove_task_wait(struct task_struct *task)
 {
-	struct uintr_upid_ctx *upid_ctx;
+	struct uintr_upid_ctx *upid_ctx, *tmp;
 	unsigned long flags;
 
-	if (!is_uintr_receiver(current))
-		return -EOPNOTSUPP;
+	spin_lock_irqsave(&uintr_wait_lock, flags);
+	list_for_each_entry_safe(upid_ctx, tmp, &uintr_wait_list, node) {
+		if (upid_ctx->task == task) {
+			pr_debug("wait: Removing task %d from wait\n",
+				 upid_ctx->task->pid);
+			upid_ctx->upid->nc.nv = UINTR_NOTIFICATION_VECTOR;
+			upid_ctx->waiting = false;
+			list_del(&upid_ctx->node);
+		}
+	}
+	spin_unlock_irqrestore(&uintr_wait_lock, flags);
+}
+
+void uintr_switch_to_kernel_vector(struct task_struct *t)
+{
+	struct uintr_upid_ctx *upid_ctx;
+	unsigned long flags;
 
-	upid_ctx = current->thread.ui_recv->upid_ctx;
+	upid_ctx = t->thread.ui_recv->upid_ctx;
 	upid_ctx->upid->nc.nv = UINTR_KERNEL_VECTOR;
 	upid_ctx->waiting = true;
 	spin_lock_irqsave(&uintr_wait_lock, flags);
 	list_add(&upid_ctx->node, &uintr_wait_list);
 	spin_unlock_irqrestore(&uintr_wait_lock, flags);
+}
+
+int uintr_receiver_wait(ktime_t *expires)
+{
+	struct task_struct *tsk = current;
+	struct hrtimer_sleeper t;
+
+	if (!is_uintr_receiver(tsk))
+		return -EOPNOTSUPP;
+
+	if (expires && *expires == 0)
+		return 0;
+
+	uintr_switch_to_kernel_vector(tsk);
+
+	hrtimer_init_sleeper_on_stack(&t, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+	hrtimer_set_expires_range_ns(&t.timer, *expires, 0);
+	hrtimer_sleeper_start_expires(&t, HRTIMER_MODE_REL);
 
 	set_current_state(TASK_INTERRUPTIBLE);
-	schedule();
 
-	return -EINTR;
+	if (t.task)
+		schedule();
+
+	hrtimer_cancel(&t.timer);
+	destroy_hrtimer_on_stack(&t.timer);
+
+	if (!t.task)
+		uintr_remove_task_wait(tsk);
+
+	__set_current_state(TASK_RUNNING);
+	pr_debug("recv: Returned from schedule task=%d\n", current->pid);
+
+	return !t.task ? 0 : -EINTR;
 }
 
 /*
@@ -532,24 +578,6 @@ void uintr_wake_up_process(void)
 	spin_unlock_irqrestore(&uintr_wait_lock, flags);
 }
 
-/* Called when task is unregistering/exiting */
-static void uintr_remove_task_wait(struct task_struct *task)
-{
-	struct uintr_upid_ctx *upid_ctx, *tmp;
-	unsigned long flags;
-
-	spin_lock_irqsave(&uintr_wait_lock, flags);
-	list_for_each_entry_safe(upid_ctx, tmp, &uintr_wait_list, node) {
-		if (upid_ctx->task == task) {
-			pr_debug("wait: Removing task %d from wait\n",
-				 upid_ctx->task->pid);
-			upid_ctx->upid->nc.nv = UINTR_NOTIFICATION_VECTOR;
-			upid_ctx->waiting = false;
-			list_del(&upid_ctx->node);
-		}
-	}
-	spin_unlock_irqrestore(&uintr_wait_lock, flags);
-}
 
 int do_uintr_unregister_handler(void)
 {
@@ -810,7 +838,7 @@ void switch_uintr_return(void)
 		 */
 		
 		if (READ_ONCE(upid->puir)){
-			printk("sending self ipi\n");
+			// printk("sending self ipi\n");
 			apic->send_IPI_self(UINTR_NOTIFICATION_VECTOR);
 		}
 	}
diff --git a/arch/x86/kernel/uintr_fd.c b/arch/x86/kernel/uintr_fd.c
index 891c4568d60b..8ddc6a7575bf 100644
--- a/arch/x86/kernel/uintr_fd.c
+++ b/arch/x86/kernel/uintr_fd.c
@@ -301,16 +301,23 @@ out_fdput:
 }
 
 /*
- * sys_uintr_wait - Wait for a user interrupt
+ * sys_uintr_wait - Wait for a user interrupt for the specified time
  */
-SYSCALL_DEFINE1(uintr_wait, unsigned int, flags)
+SYSCALL_DEFINE2(uintr_wait, u64, usec, unsigned int, flags)
 {
+	ktime_t expires;
+
 	if (!uintr_arch_enabled())
 		return -EOPNOTSUPP;
 
 	if (flags)
 		return -EINVAL;
 
-	/* TODO: Add a timeout option */
-	return uintr_receiver_wait();
+	if (usec == 0)
+		return 0;
+
+	/* For now, use a default timeout value of 100 usec */
+	/* For qemu 2575 is recommend*/
+	expires = usec * NSEC_PER_USEC;
+	return uintr_receiver_wait(&expires);
 }