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Re: [Qemu-devel] [RFC 1/2] spec/vhost-user: Introduce secondary channel
From: |
Marc-André Lureau |
Subject: |
Re: [Qemu-devel] [RFC 1/2] spec/vhost-user: Introduce secondary channel for slave initiated requests |
Date: |
Tue, 11 Apr 2017 13:06:59 +0000 |
Hi
On Tue, Apr 11, 2017 at 12:10 PM Maxime Coquelin <address@hidden>
wrote:
> This vhost-user specification update aims at enabling the
> slave to send requests to the master using a dedicated socket
> created by the master.
>
> It can be used for example when the slave implements a device
> IOTLB to send cache miss requests to the master.
>
> The message types list is updated with an "Initiator" field to
> indicate for each type whether the master and/or slave can
> initiate the request.
>
> Signed-off-by: Maxime Coquelin <address@hidden>
>
This is very similar to a patch I proposed for shutdown slave initiated
requests:
https://lists.gnu.org/archive/html/qemu-devel/2016-04/msg00095.html
> ---
> docs/specs/vhost-user.txt | 38 ++++++++++++++++++++++++++++++++++++++
> 1 file changed, 38 insertions(+)
>
> diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt
> index 036890f..b365047 100644
> --- a/docs/specs/vhost-user.txt
> +++ b/docs/specs/vhost-user.txt
> @@ -139,6 +139,7 @@ in the ancillary data:
> * VHOST_USER_SET_VRING_KICK
> * VHOST_USER_SET_VRING_CALL
> * VHOST_USER_SET_VRING_ERR
> + * VHOST_USER_SET_SLAVE_REQ_FD
>
>
I like "slave-req-fd" better than "slave-fd"
> If Master is unable to send the full message or receives a wrong reply it
> will
> close the connection. An optional reconnection mechanism can be
> implemented.
> @@ -150,6 +151,11 @@ As older slaves don't support negotiating protocol
> features,
> a feature bit was dedicated for this purpose:
> #define VHOST_USER_F_PROTOCOL_FEATURES 30
>
> +If the slave supports VHOST_USER_PROTOCOL_F_SLAVE_REQ protocol feature,
> the
> +master may create a secondary Unix domain socket and send its file
> descriptor
> +to the slave using VHOST_USER_SET_SLAVE_REQ_FD request. This new channel
> enables
> +the slave to send message requests and master to send message replies.
> +
> Starting and stopping rings
> ----------------------
> Client must only process each ring when it is started.
> @@ -260,6 +266,7 @@ Protocol features
> #define VHOST_USER_PROTOCOL_F_RARP 2
> #define VHOST_USER_PROTOCOL_F_REPLY_ACK 3
> #define VHOST_USER_PROTOCOL_F_MTU 4
> +#define VHOST_USER_PROTOCOL_F_SLAVE_REQ 5
>
> Message types
> -------------
> @@ -268,6 +275,7 @@ Message types
>
> Id: 1
> Equivalent ioctl: VHOST_GET_FEATURES
> + Initiator: Master
> Master payload: N/A
> Slave payload: u64
>
> @@ -279,6 +287,7 @@ Message types
>
> Id: 2
> Ioctl: VHOST_SET_FEATURES
> + Initiator: Master
> Master payload: u64
>
> Enable features in the underlying vhost implementation using a
> bitmask.
> @@ -289,6 +298,7 @@ Message types
>
> Id: 15
> Equivalent ioctl: VHOST_GET_FEATURES
> + Initiator: Master
> Master payload: N/A
> Slave payload: u64
>
> @@ -302,6 +312,7 @@ Message types
>
> Id: 16
> Ioctl: VHOST_SET_FEATURES
> + Initiator: Master
> Master payload: u64
>
> Enable protocol features in the underlying vhost implementation.
> @@ -314,6 +325,7 @@ Message types
>
> Id: 3
> Equivalent ioctl: VHOST_SET_OWNER
> + Initiator: Master
> Master payload: N/A
>
> Issued when a new connection is established. It sets the current
> Master
> @@ -323,6 +335,7 @@ Message types
> * VHOST_USER_RESET_OWNER
>
> Id: 4
> + Initiator: Master
> Master payload: N/A
>
> This is no longer used. Used to be sent to request disabling
> @@ -335,6 +348,7 @@ Message types
>
> Id: 5
> Equivalent ioctl: VHOST_SET_MEM_TABLE
> + Initiator: Master
> Master payload: memory regions description
>
> Sets the memory map regions on the slave so it can translate the
> vring
> @@ -346,6 +360,7 @@ Message types
>
> Id: 6
> Equivalent ioctl: VHOST_SET_LOG_BASE
> + Initiator: Master
> Master payload: u64
> Slave payload: N/A
>
> @@ -360,6 +375,7 @@ Message types
>
> Id: 7
> Equivalent ioctl: VHOST_SET_LOG_FD
> + Initiator: Master
> Master payload: N/A
>
> Sets the logging file descriptor, which is passed as ancillary data.
> @@ -368,6 +384,7 @@ Message types
>
> Id: 8
> Equivalent ioctl: VHOST_SET_VRING_NUM
> + Initiator: Master
> Master payload: vring state description
>
> Set the size of the queue.
> @@ -376,6 +393,7 @@ Message types
>
> Id: 9
> Equivalent ioctl: VHOST_SET_VRING_ADDR
> + Initiator: Master
> Master payload: vring address description
> Slave payload: N/A
>
> @@ -385,6 +403,7 @@ Message types
>
> Id: 10
> Equivalent ioctl: VHOST_SET_VRING_BASE
> + Initiator: Master
> Master payload: vring state description
>
> Sets the base offset in the available vring.
> @@ -393,6 +412,7 @@ Message types
>
> Id: 11
> Equivalent ioctl: VHOST_USER_GET_VRING_BASE
> + Initiator: Master
> Master payload: vring state description
> Slave payload: vring state description
>
> @@ -402,6 +422,7 @@ Message types
>
> Id: 12
> Equivalent ioctl: VHOST_SET_VRING_KICK
> + Initiator: Master
> Master payload: u64
>
> Set the event file descriptor for adding buffers to the vring. It
> @@ -415,6 +436,7 @@ Message types
>
> Id: 13
> Equivalent ioctl: VHOST_SET_VRING_CALL
> + Initiator: Master
> Master payload: u64
>
> Set the event file descriptor to signal when buffers are used. It
> @@ -428,6 +450,7 @@ Message types
>
> Id: 14
> Equivalent ioctl: VHOST_SET_VRING_ERR
> + Initiator: Master
> Master payload: u64
>
> Set the event file descriptor to signal when error occurs. It
> @@ -440,6 +463,7 @@ Message types
>
> Id: 17
> Equivalent ioctl: N/A
> + Initiator: Master
> Master payload: N/A
> Slave payload: u64
>
> @@ -451,6 +475,7 @@ Message types
>
> Id: 18
> Equivalent ioctl: N/A
> + Initiator: Master
> Master payload: vring state description
>
> Signal slave to enable or disable corresponding vring.
> @@ -461,6 +486,7 @@ Message types
>
> Id: 19
> Equivalent ioctl: N/A
> + Initiator: Master
> Master payload: u64
>
> Ask vhost user backend to broadcast a fake RARP to notify the
> migration
> @@ -475,6 +501,7 @@ Message types
>
> Id: 20
> Equivalent ioctl: N/A
> + Initiator: Master
> Master payload: u64
>
> Set host MTU value exposed to the guest.
> @@ -486,6 +513,17 @@ Message types
> If VHOST_USER_PROTOCOL_F_REPLY_ACK is negotiated, slave must respond
> with zero in case the specified MTU is valid, or non-zero otherwise.
>
> + * VHOST_USER_SET_SLAVE_REQ_FD
> +
> + Id: 21
> + Equivalent ioctl: N/A
> + Initiator: Master
> +
> + Set the socket file descriptor for slave initiated requests.
> + This request should be sent only when VHOST_USER_F_PROTOCOL_FEATURES
> + has been negotiated, and protocol feature bit
> VHOST_USER_PROTOCOL_F_SLAVE_REQ
> + bit is present in VHOST_USER_GET_PROTOCOL_FEATURES.
> +
>
looks good to me
> VHOST_USER_PROTOCOL_F_REPLY_ACK:
> -------------------------------
> The original vhost-user specification only demands replies for certain
> --
> 2.9.3
>
>
> --
Marc-André Lureau
- [Qemu-devel] [RFC 0/2] vhost-user: Specify device IOTLB support, Maxime Coquelin, 2017/04/11
- [Qemu-devel] [RFC 1/2] spec/vhost-user: Introduce secondary channel for slave initiated requests, Maxime Coquelin, 2017/04/11
- Re: [Qemu-devel] [RFC 1/2] spec/vhost-user: Introduce secondary channel for slave initiated requests,
Marc-André Lureau <=
- Re: [Qemu-devel] [RFC 1/2] spec/vhost-user: Introduce secondary channel for slave initiated requests, Maxime Coquelin, 2017/04/11
- Re: [Qemu-devel] [RFC 1/2] spec/vhost-user: Introduce secondary channel for slave initiated requests, Marc-André Lureau, 2017/04/14
- Re: [Qemu-devel] [virtio-comment] Re: [RFC 1/2] spec/vhost-user: Introduce secondary channel for slave initiated requests, Wei Wang, 2017/04/24
- Re: [Qemu-devel] [virtio-comment] Re: [RFC 1/2] spec/vhost-user: Introduce secondary channel for slave initiated requests, Maxime Coquelin, 2017/04/25
- Re: [Qemu-devel] [virtio-comment] Re: [RFC 1/2] spec/vhost-user: Introduce secondary channel for slave initiated requests, Wei Wang, 2017/04/26
[Qemu-devel] [RFC 2/2] spec/vhost-user spec: Add IOMMU support, Maxime Coquelin, 2017/04/11