From: "Liu, Changpeng" <changpeng.liu@intel.com>
To: Maxime Coquelin <maxime.coquelin@redhat.com>,
"Kulasek, TomaszX" <tomaszx.kulasek@intel.com>,
"yliu@fridaylinux.org" <yliu@fridaylinux.org>
Cc: "Verkamp, Daniel" <daniel.verkamp@intel.com>,
"Harris, James R" <james.r.harris@intel.com>,
"Wodkowski, PawelX" <pawelx.wodkowski@intel.com>,
"dev@dpdk.org" <dev@dpdk.org>,
"Tan, Jianfeng" <jianfeng.tan@intel.com>
Subject: Re: [dpdk-dev] [PATCH v2] vhost: add virtio configuration space messages
Date: Wed, 28 Mar 2018 10:03:11 +0000 [thread overview]
Message-ID: <FF7FC980937D6342B9D289F5F3C7C2625B6252FB@SHSMSX103.ccr.corp.intel.com> (raw)
In-Reply-To: <fe5a4063-1848-11b3-85b6-6f1ba7db9f20@redhat.com>
> -----Original Message-----
> From: Maxime Coquelin [mailto:maxime.coquelin@redhat.com]
> Sent: Wednesday, March 28, 2018 5:58 PM
> To: Liu, Changpeng <changpeng.liu@intel.com>; Kulasek, TomaszX
> <tomaszx.kulasek@intel.com>; yliu@fridaylinux.org
> Cc: Verkamp, Daniel <daniel.verkamp@intel.com>; Harris, James R
> <james.r.harris@intel.com>; Wodkowski, PawelX
> <pawelx.wodkowski@intel.com>; dev@dpdk.org; Tan, Jianfeng
> <jianfeng.tan@intel.com>
> Subject: Re: [dpdk-dev] [PATCH v2] vhost: add virtio configuration space
> messages
>
>
>
> On 03/28/2018 11:50 AM, Liu, Changpeng wrote:
> >
> >
> >> -----Original Message-----
> >> From: Maxime Coquelin [mailto:maxime.coquelin@redhat.com]
> >> Sent: Wednesday, March 28, 2018 5:12 PM
> >> To: Kulasek, TomaszX <tomaszx.kulasek@intel.com>; yliu@fridaylinux.org
> >> Cc: Verkamp, Daniel <daniel.verkamp@intel.com>; Harris, James R
> >> <james.r.harris@intel.com>; Wodkowski, PawelX
> >> <pawelx.wodkowski@intel.com>; dev@dpdk.org; Liu, Changpeng
> >> <changpeng.liu@intel.com>; Tan, Jianfeng <jianfeng.tan@intel.com>
> >> Subject: Re: [dpdk-dev] [PATCH v2] vhost: add virtio configuration space
> >> messages
> >>
> >>
> >>
> >> On 03/27/2018 05:35 PM, Tomasz Kulasek wrote:
> >>> This patch adds new vhost user messages GET_CONFIG and SET_CONFIG
> used
> >>> for get/set virtio device's configuration space.
> >>>
> >>> Signed-off-by: Changpeng Liu <changpeng.liu@intel.com>
> >>> Signed-off-by: Tomasz Kulasek <tomaszx.kulasek@intel.com>
> >>> ---
> >>> Changes in v2:
> >>> - code cleanup
> >>>
> >>> lib/librte_vhost/rte_vhost.h | 4 ++++
> >>> lib/librte_vhost/vhost_user.c | 22 ++++++++++++++++++++++
> >>> lib/librte_vhost/vhost_user.h | 16 ++++++++++++++++
> >>> 3 files changed, 42 insertions(+)
> >>>
> >>> diff --git a/lib/librte_vhost/rte_vhost.h b/lib/librte_vhost/rte_vhost.h
> >>> index d332069..fe30518 100644
> >>> --- a/lib/librte_vhost/rte_vhost.h
> >>> +++ b/lib/librte_vhost/rte_vhost.h
> >>> @@ -84,6 +84,10 @@ struct vhost_device_ops {
> >>> int (*new_connection)(int vid);
> >>> void (*destroy_connection)(int vid);
> >>>
> >>> + int (*get_config)(int vid, uint8_t *config, uint32_t config_len);
> >>> + int (*set_config)(int vid, uint8_t *config, uint32_t offset,
> >>> + uint32_t len, uint32_t flags);
> >>> +
> >>> void *reserved[2]; /**< Reserved for future extension */
> >>
> >> You are breaking the ABI, as you grow the size of the ops struct.
> >>
> >> Also, I'm wondering if we shouldn't have a different ops for external
> >> backends. Here these ops are more intended to the application, we could
> >> have a specific ops struct for external backends IMHO.
> >>
> >>> };
> >>>
> >>> diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
> >>> index 90ed211..0ed6a5a 100644
> >>> --- a/lib/librte_vhost/vhost_user.c
> >>> +++ b/lib/librte_vhost/vhost_user.c
> >>> @@ -50,6 +50,8 @@ static const char
> *vhost_message_str[VHOST_USER_MAX]
> >> = {
> >>> [VHOST_USER_NET_SET_MTU] = "VHOST_USER_NET_SET_MTU",
> >>> [VHOST_USER_SET_SLAVE_REQ_FD] =
> >> "VHOST_USER_SET_SLAVE_REQ_FD",
> >>> [VHOST_USER_IOTLB_MSG] = "VHOST_USER_IOTLB_MSG",
> >>> + [VHOST_USER_GET_CONFIG] = "VHOST_USER_GET_CONFIG",
> >>> + [VHOST_USER_SET_CONFIG] = "VHOST_USER_SET_CONFIG",
> >>> };
> >>>
> >>> static uint64_t
> >>> @@ -1355,6 +1357,7 @@ vhost_user_msg_handler(int vid, int fd)
> >>> * would cause a dead lock.
> >>> */
> >>> switch (msg.request.master) {
> >>> + case VHOST_USER_SET_CONFIG:
> >>
> >> It seems VHOST_USER_GET_CONFIG is missing here.
> >>
> >>> case VHOST_USER_SET_FEATURES:
> >>> case VHOST_USER_SET_PROTOCOL_FEATURES:
> >>> case VHOST_USER_SET_OWNER:
> >>> @@ -1380,6 +1383,25 @@ vhost_user_msg_handler(int vid, int fd)
> >>> }
> >>>
> >>> switch (msg.request.master) {
> >>> + case VHOST_USER_GET_CONFIG:
> >>> + if (dev->notify_ops->get_config(dev->vid,
> >> Please check ->get_config is set before calling it.
> >>
> >>> + msg.payload.config.region,
> >>> + msg.payload.config.size) != 0) {
> >>> + msg.size = sizeof(uint64_t);
> >>> + }
> >>> + send_vhost_reply(fd, &msg);
> >>> + break;
> >>> + case VHOST_USER_SET_CONFIG:
> >>> + if ((dev->notify_ops->set_config(dev->vid,
> >> Ditto.
> >>
> >>> + msg.payload.config.region,
> >>> + msg.payload.config.offset,
> >>> + msg.payload.config.size,
> >>> + msg.payload.config.flags)) != 0) {
> >>> + ret = 1;
> >>> + } else {
> >>> + ret = 0;
> >>> + }
> >>
> >> ret = dev->notify_ops->set_config instead?
> >>> + break;
> >>> case VHOST_USER_GET_FEATURES:
> >>> msg.payload.u64 = vhost_user_get_features(dev);
> >>> msg.size = sizeof(msg.payload.u64);
> >>> diff --git a/lib/librte_vhost/vhost_user.h b/lib/librte_vhost/vhost_user.h
> >>> index d4bd604..25cc026 100644
> >>> --- a/lib/librte_vhost/vhost_user.h
> >>> +++ b/lib/librte_vhost/vhost_user.h
> >>> @@ -14,6 +14,11 @@
> >>>
> >>> #define VHOST_MEMORY_MAX_NREGIONS 8
> >>>
> >>> +/*
> >>> + * Maximum size of virtio device config space
> >>> + */
> >>> +#define VHOST_USER_MAX_CONFIG_SIZE 256
> >>> +
> >>> #define VHOST_USER_PROTOCOL_F_MQ 0
> >>> #define VHOST_USER_PROTOCOL_F_LOG_SHMFD 1
> >>> #define VHOST_USER_PROTOCOL_F_RARP 2
> >>
> >> Shouldn't there be a protocol feature associated to these new messages?
> >> Else how QEMU knows the backend supports it or not?
> >>
> >> I looked at QEMU code and indeed no protocol feature associated, that's
> >> strange...
> > Nice to have, for now not all the QEMU host driver need to get this
> configuration space from slave backend
> > when getting start. This message can be used for migration of vhost-user
> devices.
>
> So if QEMU sends this message but the DPDK version does not support it
> yet, vhost_user_msg_handler() will return an error ("vhost read
> incorrect message") and the socket will be closed.
>
> How do we overcome this? I think we really need a spec update ASAP,
> before QEMU v2.12 is out (-rc1 already).
>
> Do you have time to take care of this?
For now there are no other users except us care about this message, :), it's no hurry.
I can take this after QEMU 2.12 release adding a new protocol feature bit.
>
> Thanks,
> Maxime
next prev parent reply other threads:[~2018-03-28 10:03 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-27 15:17 [dpdk-dev] [PATCH] " Tomasz Kulasek
2018-03-27 15:35 ` [dpdk-dev] [PATCH v2] " Tomasz Kulasek
2018-03-28 9:11 ` Maxime Coquelin
2018-03-28 9:19 ` Wodkowski, PawelX
2018-03-28 9:33 ` Maxime Coquelin
2018-03-28 9:48 ` Maxime Coquelin
2018-03-28 9:50 ` Liu, Changpeng
2018-03-28 9:57 ` Maxime Coquelin
2018-03-28 10:03 ` Liu, Changpeng [this message]
2018-03-28 10:11 ` Maxime Coquelin
2018-03-28 10:23 ` Liu, Changpeng
2018-03-28 10:56 ` Maxime Coquelin
2018-04-19 14:39 ` Maxime Coquelin
2018-04-20 0:32 ` Liu, Changpeng
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