From nobody Mon Feb 9 17:36:15 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1491905562051462.65330010333446; Tue, 11 Apr 2017 03:12:42 -0700 (PDT) Received: from localhost ([::1]:38293 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cxsmu-0001ac-Rl for importer@patchew.org; Tue, 11 Apr 2017 06:12:40 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34004) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cxski-0008Ih-Ey for qemu-devel@nongnu.org; Tue, 11 Apr 2017 06:10:25 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cxskh-0002x8-8q for qemu-devel@nongnu.org; Tue, 11 Apr 2017 06:10:24 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43490) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cxskh-0002wk-0H for qemu-devel@nongnu.org; Tue, 11 Apr 2017 06:10:23 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 1864233887F; Tue, 11 Apr 2017 10:10:22 +0000 (UTC) Received: from localhost.localdomain (ovpn-112-20.ams2.redhat.com [10.36.112.20]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4119D53CC4; Tue, 11 Apr 2017 10:10:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 1864233887F Authentication-Results: ext-mx05.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx05.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=maxime.coquelin@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 1864233887F From: Maxime Coquelin To: mst@redhat.com, vkaplans@redhat.com, jasowang@redhat.com, wexu@redhat.com, peterx@redhat.com, yuanhan.liu@linux.intel.com, virtio-comment@lists.oasis-open.org, qemu-devel@nongnu.org Date: Tue, 11 Apr 2017 12:10:02 +0200 Message-Id: <20170411101002.28451-3-maxime.coquelin@redhat.com> In-Reply-To: <20170411101002.28451-1-maxime.coquelin@redhat.com> References: <20170411101002.28451-1-maxime.coquelin@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Tue, 11 Apr 2017 10:10:22 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [RFC 2/2] spec/vhost-user spec: Add IOMMU support 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: Maxime Coquelin Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" This patch specifies the master/slave communication to support device IOTLB implementation in slave. The vhost_iotlb_msg structure introduced for kernel backends is re-used, making the design close between the two backends. An exception is the use of the secondary channel to enable the slave to send IOTLB miss requests to the master. Signed-off-by: Maxime Coquelin --- docs/specs/vhost-user.txt | 56 +++++++++++++++++++++++++++++++++++++++++++= ++++ 1 file changed, 56 insertions(+) diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt index b365047..048a4d6 100644 --- a/docs/specs/vhost-user.txt +++ b/docs/specs/vhost-user.txt @@ -97,6 +97,23 @@ Depending on the request type, payload can be: log offset: offset from start of supplied file descriptor where logging starts (i.e. where guest address 0 would be logged) =20 + * An IOTLB message + --------------------------------------------------------- + | iova | size | user address | permissions flags | type | + --------------------------------------------------------- + + IOVA: a 64-bit guest I/O virtual address + Size: a 64-bit size + User address: a 64-bit user address + Permissions flags: a 8-bit bit field: + - Bit 0: Read access + - Bit 1: Write access + Type: a 8-bit IOTLB message type: + - 1: IOTLB miss + - 2: IOTLB update + - 3: IOTLB invalidate + - 4: IOTLB access fail + In QEMU the vhost-user message is implemented with the following struct: =20 typedef struct VhostUserMsg { @@ -109,6 +126,7 @@ typedef struct VhostUserMsg { struct vhost_vring_addr addr; VhostUserMemory memory; VhostUserLog log; + struct vhost_iotlb_msg iotlb; }; } QEMU_PACKED VhostUserMsg; =20 @@ -258,6 +276,30 @@ Once the source has finished migration, rings will be = stopped by the source. No further update must be done before rings are restarted. =20 +IOMMU support +------------- + +When the VIRTIO_F_IOMMU_PLATFORM feature has been negotiated, the master h= as +to send IOTLB entries update & invalidation by sending VHOST_USER_IOTLB_MSG +requests to the slave with a struct vhost_iotlb_msg payload. For update ev= ents, +the iotlb payload has to be filled with the update message type (2), the I= /O +virtual address, the size, the user virtual address, and the permissions +flags. For invalidation events, the iotlb payload has to be filled with the +update message type (3), the I/O virtual address and the size. On success,= the +slave is expected to reply with a zero payload, non-zero otherwise. + +When the VHOST_USER_PROTOCOL_F_SLAVE_REQ is supported by the slave, and the +master initiated the slave to master communication channel using the +VHOST_USER_SET_SLAVE_REQ_FD request, the slave can send IOTLB miss and acc= ess +failure events by sending VHOST_USER_IOTLB_MSG requests to the master with= a +struct vhost_iotlb_msg payload. For miss events, the iotlb payload has to = be +filled with the miss message type (1), the I/O virtual address and the +permissions flags. For access failure event, the iotlb payload has to be +filled with the access failure message type (4), the I/O virtual address a= nd +the permissions flags. On success, the master is expected to reply when t= he +request has been handled (for example, on miss requests, once the device I= OTLB +has been updated) with a zero payload, non-zero otherwise. + Protocol features ----------------- =20 @@ -524,6 +566,20 @@ Message types has been negotiated, and protocol feature bit VHOST_USER_PROTOCOL_F_= SLAVE_REQ bit is present in VHOST_USER_GET_PROTOCOL_FEATURES. =20 + * VHOST_USER_IOTLB_MSG + + Id: 22 + Equivalent ioctl: N/A (equivalent to VHOST_IOTLB_MSG message type) + Initiator: Master or slave + + Send IOTLB messages with struct vhost_iotlb_msg as payload. + Master sends such requests to update and invalidate entries in the d= evice + IOTLB. Slave sends such requests to notify of an IOTLB miss, or an I= OTLB + access failure. The recipient has to acknowledge the request with + sending zero as u64 payload for success, non-zero otherwise. + This request should be send only when VIRTIO_F_IOMMU_PLATFORM feature + has been successfully negotiated. + VHOST_USER_PROTOCOL_F_REPLY_ACK: ------------------------------- The original vhost-user specification only demands replies for certain --=20 2.9.3