vfio/device: add vfio_disable_irq_from_start

To disable (de-assign) one or more IRQs from vfio-pci kernel driver, irq_set data -1 should be passed to irq_set->data. uapi <linux/vfio.h> says that value -1 with DATA_EVENTFD|ACTION_TRIGGER) will de-assign interrupts if already assigned. This patch fixes de-assign behavior by replacing DATA_NONE to DATA_EVENTFD with data -1 along with adding a new API to disable specific interrupts with start and count. Signed-off-by: Minwoo Im <[email protected]>
SamsungDS · Nov 19, 2024 · d6d09e1 · d6d09e1
1 parent d5102dc
commit d6d09e1
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Showing 2 changed files with 43 additions and 6 deletions.
diff --git a/include/vfn/vfio/device.h b/include/vfn/vfio/device.h
@@ -61,6 +61,18 @@ int vfio_set_irq_from_start(struct vfio_device *dev, int *eventfds, int start, i
  */
 int vfio_disable_irq(struct vfio_device *dev);
 
+/**
+ * vfio_disable_irq_from_start - Disable number of count IRQs from given start
+ * @dev: &struct vfio_device
+ * @start: start irq number
+ * @count: number of eventfds
+ *
+ * Disable given number of IRQs from start.
+ *
+ * Return: ``0`` on success, ``-1`` on error and sets ``errno``.
+ */
+int vfio_disable_irq_from_start(struct vfio_device *dev, int start, int count);
+
 /**
  * vfio_reset - reset vfio device
  * @dev: &struct vfio_device to reset

diff --git a/src/vfio/device.c b/src/vfio/device.c
@@ -87,18 +87,33 @@ int vfio_set_irq_from_start(struct vfio_device *dev, int *eventfds, int start,
 	return __vfio_set_irq(dev, eventfds, start, count);
 }
 
-int vfio_disable_irq(struct vfio_device *dev)
+static int __vfio_disable_irq(struct vfio_device *dev, int start, int count)
 {
-	struct vfio_irq_set irq_set;
+	struct vfio_irq_set *irq_set;
+	size_t irq_set_size;
+	int *data;
 	int ret;
 
-	irq_set = (struct vfio_irq_set) {
-		.argsz = sizeof(irq_set),
-		.flags = VFIO_IRQ_SET_DATA_NONE | VFIO_IRQ_SET_ACTION_TRIGGER,
+	irq_set_size = sizeof(*irq_set) + sizeof(int) * count;
+	irq_set = xmalloc(irq_set_size);
+
+	data = xmalloc(sizeof(int) * count);
+	for (int i = 0; i < count; i++)
+		data[i] = -1;
+
+	*irq_set = (struct vfio_irq_set) {
+		.argsz = (uint32_t)irq_set_size,
+		.flags = VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_TRIGGER,
 		.index = dev->irq_info.index,
+		.start = start,
+		.count = count,
 	};
 
-	ret = ioctl(dev->fd, VFIO_DEVICE_SET_IRQS, &irq_set);
+	memcpy(irq_set->data, data, sizeof(int) * count);
+
+	ret = ioctl(dev->fd, VFIO_DEVICE_SET_IRQS, irq_set);
+	free(data);
+	free(irq_set);
 
 	if (ret) {
 		log_debug("failed to disable device irq\n");
@@ -108,6 +123,16 @@ int vfio_disable_irq(struct vfio_device *dev)
 	return 0;
 }
 
+int vfio_disable_irq(struct vfio_device *dev)
+{
+	return __vfio_disable_irq(dev, 0, dev->irq_info.count);
+}
+
+int vfio_disable_irq_from_start(struct vfio_device *dev, int start, int count)
+{
+	return __vfio_disable_irq(dev, start, count);
+}
+
 int vfio_reset(struct vfio_device *dev)
 {
 	if (!(dev->device_info.flags & VFIO_DEVICE_FLAGS_RESET)) {