[PATCH v2 4/5] vduse: Support querying IOLTB information

Xie Yongji
2022-07-06T05:06:12Z

This introduces a new ioctl: VDUSE_IOTLB_GET_INFO to
support querying IOLTB information such as bounce
buffer size.

Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
---
drivers/vdpa/vdpa_user/vduse_dev.c | 13 +++++++++++++
include/uapi/linux/vduse.h | 17 +++++++++++++++++
2 files changed, 30 insertions(+)

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 3bc27de58f46..c47a5d9765cf 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -1089,6 +1089,19 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
ret = vduse_dev_queue_irq_work(dev, &dev->vqs[index].inject);
break;
}
+ case VDUSE_IOTLB_GET_INFO: {
+ struct vduse_iotlb_info iotlb;
+
+ iotlb.bounce_iova = 0;
+ iotlb.bounce_size = dev->domain->bounce_size;
+
+ ret = -EFAULT;
+ if (copy_to_user(argp, &iotlb, sizeof(iotlb)))
+ break;
+
+ ret = 0;
+ break;
+ }
default:
ret = -ENOIOCTLCMD;
break;
diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h
index 7cfe1c1280c0..c201b7a77c2c 100644
--- a/include/uapi/linux/vduse.h
+++ b/include/uapi/linux/vduse.h
@@ -210,6 +210,23 @@ struct vduse_vq_eventfd {
*/
#define VDUSE_VQ_INJECT_IRQ _IOW(VDUSE_BASE, 0x17, __u32)

+/**
+ * struct vduse_iotlb_info - IOTLB information
+ * @bounce_iova: start IOVA of bounce buffer
+ * @bounce_size: bounce buffer size
+ * @reserved: for future use, needs to be initialized to zero
+ *
+ * Structure used by VDUSE_IOTLB_GET_INFO ioctl to get IOTLB information.
+ */
+struct vduse_iotlb_info {
+ __u64 bounce_iova;
+ __u64 bounce_size;
+ __u64 reserved[2];
+};
+
+/* Get IOTLB information, e.g. bounce buffer size */
+#define VDUSE_IOTLB_GET_INFO _IOR(VDUSE_BASE, 0x18, struct vduse_iotlb_info)
+
/* The control messages definition for read(2)/write(2) on /dev/vduse/$NAME */

/**
--
2.20.1