From patchwork Mon Dec 19 11:05:52 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Wang, Wei W" X-Patchwork-Id: 707038 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3thyp05ykQz9t1C for ; Mon, 19 Dec 2016 22:08:24 +1100 (AEDT) Received: from localhost ([::1]:44599 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cIvnq-0004Mn-Lm for incoming@patchwork.ozlabs.org; Mon, 19 Dec 2016 06:08:22 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56620) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cIvmh-0003M0-9q for qemu-devel@nongnu.org; Mon, 19 Dec 2016 06:07:12 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cIvmf-0001aU-0h for qemu-devel@nongnu.org; Mon, 19 Dec 2016 06:07:11 -0500 Received: from mga05.intel.com ([192.55.52.43]:37967) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cIvme-0001XE-NY for qemu-devel@nongnu.org; Mon, 19 Dec 2016 06:07:08 -0500 Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga105.fm.intel.com with ESMTP; 19 Dec 2016 03:07:08 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos; i="5.33,373,1477983600"; d="scan'208"; a="1073938894" Received: from devel-ww.sh.intel.com ([10.239.48.105]) by orsmga001.jf.intel.com with ESMTP; 19 Dec 2016 03:07:04 -0800 From: Wei Wang To: marcandre.lureau@gmail.com, mst@redhat.com, stefanha@redhat.com, pbonzini@redhat.com, qemu-devel@nongnu.org, virtio-comment@lists.oasis-open.org Date: Mon, 19 Dec 2016 19:05:52 +0800 Message-Id: <1482145554-88823-2-git-send-email-wei.w.wang@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1482145554-88823-1-git-send-email-wei.w.wang@intel.com> References: <1482145554-88823-1-git-send-email-wei.w.wang@intel.com> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 192.55.52.43 Subject: [Qemu-devel] [PATCH v3 1/3] spec/vhost-user: extend vhost-user to support the vhost-pci based inter-vm communiaction X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Wei Wang Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" The protocol feature, VHOST_USER_PROTOCOL_F_VHOST_PCI, indicates the support of vhost-pci. The vhost-pci extension requires the master side implementation to support an asynchronous socket read method. This is used when the slave side vhost-pci device and driver finishes the feature bits negotiation. The negotiated feature bits are sent to the master. If the feature bits sent by the slave are a subset of the ones that were sent by the master, the master should perform a reset of the master device (e.g. virtio_net), to re-negotiate the feature bits using the ones sent by the slave. Signed-off-by: Wei Wang --- docs/specs/vhost-user.txt | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt index d70bd83..18e49d0 100644 --- a/docs/specs/vhost-user.txt +++ b/docs/specs/vhost-user.txt @@ -17,12 +17,15 @@ The protocol defines 2 sides of the communication, master and slave. Master is the application that shares its virtqueues, in our case QEMU. Slave is the consumer of the virtqueues. -In the current implementation QEMU is the Master, and the Slave is intended to +In the traditional implementation QEMU is the master, and the slave is intended to be a software Ethernet switch running in user space, such as Snabbswitch. Master and slave can be either a client (i.e. connecting) or server (listening) in the socket communication. +The current vhost-user protocol is extended to support the vhost-pci based inter-VM +communication. In this case, both the slave and master are QEMU instances. + Message Specification --------------------- @@ -36,7 +39,7 @@ consists of 3 header fields and a payload: * Request: 32-bit type of the request * Flags: 32-bit bit field: - Lower 2 bits are the version (currently 0x01) - - Bit 2 is the reply flag - needs to be sent on each reply from the slave + - Bit 2 is the reply flag - needs to be sent on each reply - Bit 3 is the need_reply flag - see VHOST_USER_PROTOCOL_F_REPLY_ACK for details. * Size - 32-bit size of the payload @@ -119,9 +122,9 @@ The protocol for vhost-user is based on the existing implementation of vhost for the Linux Kernel. Most messages that can be sent via the Unix domain socket implementing vhost-user have an equivalent ioctl to the kernel implementation. -The communication consists of master sending message requests and slave sending -message replies. Most of the requests don't require replies. Here is a list of -the ones that do: +Traditionally, the communication consists of master sending message requests and +slave sending message replies. Most of the requests don't require replies. Here +is a list of the ones that do: * VHOST_USER_GET_FEATURES * VHOST_USER_GET_PROTOCOL_FEATURES @@ -130,6 +133,10 @@ the ones that do: [ Also see the section on REPLY_ACK protocol extension. ] +Currently, the communication also supports the slave actively sending messages +to the master. Here is a list of them: + * VHOST_USER_SET_FEATURES + There are several messages that the master sends with file descriptors passed in the ancillary data: @@ -259,6 +266,7 @@ Protocol features #define VHOST_USER_PROTOCOL_F_LOG_SHMFD 1 #define VHOST_USER_PROTOCOL_F_RARP 2 #define VHOST_USER_PROTOCOL_F_REPLY_ACK 3 +#define VHOST_USER_PROTOCOL_F_VHOST_PCI 4 Message types ------------- @@ -279,8 +287,9 @@ Message types Id: 2 Ioctl: VHOST_SET_FEATURES Master payload: u64 + Slave payload: u64 - Enable features in the underlying vhost implementation using a bitmask. + Feature bits negotiation between the master and slave using a bitmask. Feature bit VHOST_USER_F_PROTOCOL_FEATURES signals slave support for VHOST_USER_GET_PROTOCOL_FEATURES and VHOST_USER_SET_PROTOCOL_FEATURES.