Re: [RFC 02/10] vhost: add 3 commands for vhost-vdpa

[Jason Wang]

在 2022/1/5 下午2:40, Longpeng (Mike, Cloud Infrastructure Service Product 
Dept.) 写道:

-----Original Message-----
From: Jason Wang [mailto:jasow...@redhat.com]
Sent: Wednesday, January 5, 2022 12:36 PM
To: Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
<longpe...@huawei.com>
Cc: Stefan Hajnoczi <stefa...@redhat.com>; mst <m...@redhat.com>; Stefano
Garzarella <sgarz...@redhat.com>; Cornelia Huck <coh...@redhat.com>; pbonzini
<pbonz...@redhat.com>; Gonglei (Arei) <arei.gong...@huawei.com>; Yechuan
<yech...@huawei.com>; Huangzhichao <huangzhic...@huawei.com>; qemu-devel
<qemu-devel@nongnu.org>
Subject: Re: [RFC 02/10] vhost: add 3 commands for vhost-vdpa

On Wed, Jan 5, 2022 at 8:59 AM Longpeng(Mike) <longpe...@huawei.com> wrote:
From: Longpeng <longpe...@huawei.com>

To support generic vdpa deivce, we need add the following ioctls:
- GET_VECTORS_NUM: the count of vectors that supported
Does this mean MSI vectors? If yes, it looks like a layer violation:
vhost is transport independent.  And it reveals device implementation
details which block (cross vendor) migration.

Can we set the VirtIOPCIProxy.nvectors to "the count of virtqueues + 1 
(config)" ?


That should work.

Thanks



Thanks

- GET_CONFIG_SIZE: the size of the virtio config space
- GET_VQS_NUM: the count of virtqueues that exported

Signed-off-by: Longpeng <longpe...@huawei.com>
---
  linux-headers/linux/vhost.h | 10 ++++++++++
  1 file changed, 10 insertions(+)

diff --git a/linux-headers/linux/vhost.h b/linux-headers/linux/vhost.h
index c998860d7b..c5edd75d15 100644
--- a/linux-headers/linux/vhost.h
+++ b/linux-headers/linux/vhost.h
@@ -150,4 +150,14 @@
  /* Get the valid iova range */
  #define VHOST_VDPA_GET_IOVA_RANGE      _IOR(VHOST_VIRTIO, 0x78, \
                                              struct vhost_vdpa_iova_range)
+
+/* Get the number of vectors */
+#define VHOST_VDPA_GET_VECTORS_NUM     _IOR(VHOST_VIRTIO, 0x79, int)
+
+/* Get the virtio config size */
+#define VHOST_VDPA_GET_CONFIG_SIZE     _IOR(VHOST_VIRTIO, 0x80, int)
+
+/* Get the number of virtqueues */
+#define VHOST_VDPA_GET_VQS_NUM         _IOR(VHOST_VIRTIO, 0x81, int)
+
  #endif
--
2.23.0