On Wed, Jun 1, 2022 at 7:35 AM Eli Cohen [off-list ref] wrote:

quoted

From: Eugenio Pérez <eperezma@redhat.com>
Sent: Thursday, May 26, 2022 3:44 PM
To: Michael S. Tsirkin <mst@redhat.com>; kvm@vger.kernel.org; virtualization@lists.linux-foundation.org; linux-kernel@vger.kernel.org;
Jason Wang [off-list ref]; netdev@vger.kernel.org
Cc: martinh@xilinx.com; Stefano Garzarella <sgarzare@redhat.com>; martinpo@xilinx.com; lvivier@redhat.com; pabloc@xilinx.com;
Parav Pandit [off-list ref]; Eli Cohen [off-list ref]; Dan Carpenter [off-list ref]; Xie Yongji
[off-list ref]; Christophe JAILLET [off-list ref]; Zhang Min [off-list ref]; Wu Zongyong
[off-list ref]; lulu@redhat.com; Zhu Lingshan [off-list ref]; Piotr.Uminski@intel.com; Si-Wei Liu <si-
wei.liu@oracle.com>; ecree.xilinx@gmail.com; gautam.dawar@amd.com; habetsm.xilinx@gmail.com; tanuj.kamde@amd.com;
hanand@xilinx.com; dinang@xilinx.com; Longpeng [off-list ref]
Subject: [PATCH v4 1/4] vdpa: Add stop operation

This operation is optional: It it's not implemented, backend feature bit
will not be exposed.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 include/linux/vdpa.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
index 15af802d41c4..ddfebc4e1e01 100644
--- a/include/linux/vdpa.h
+++ b/include/linux/vdpa.h

@@ -215,6 +215,11 @@ struct vdpa_map_file {
  * @reset:                   Reset device
  *                           @vdev: vdpa device
  *                           Returns integer: success (0) or error (< 0)
+ * @stop:                    Stop or resume the device (optional, but it must
+ *                           be implemented if require device stop)
+ *                           @vdev: vdpa device
+ *                           @stop: stop (true), not stop (false)
+ *                           Returns integer: success (0) or error (< 0)

I assume after successful "stop" the device is guaranteed to stop processing descriptors and after resume it may process descriptors?
If that is so, I think it should be clear in the change log.

Yes.

It's better described in the changelog of vdpa sim change, maybe it's
better to move here.

Thanks!

quoted

  * @get_config_size:         Get the size of the configuration space includes
  *                           fields that are conditional on feature bits.
  *                           @vdev: vdpa device

@@ -316,6 +321,7 @@ struct vdpa_config_ops {
      u8 (*get_status)(struct vdpa_device *vdev);
      void (*set_status)(struct vdpa_device *vdev, u8 status);
      int (*reset)(struct vdpa_device *vdev);
+     int (*stop)(struct vdpa_device *vdev, bool stop);
      size_t (*get_config_size)(struct vdpa_device *vdev);
      void (*get_config)(struct vdpa_device *vdev, unsigned int offset,
                         void *buf, unsigned int len);
--

2.31.1