From patchwork Sun Nov 6 17:46:21 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yishai Hadas X-Patchwork-Id: 13033519 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 76BC0C4332F for ; Sun, 6 Nov 2022 17:47:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230162AbiKFRr0 (ORCPT ); Sun, 6 Nov 2022 12:47:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44576 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230398AbiKFRrY (ORCPT ); Sun, 6 Nov 2022 12:47:24 -0500 Received: from NAM12-DM6-obe.outbound.protection.outlook.com (mail-dm6nam12on2083.outbound.protection.outlook.com [40.107.243.83]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4F6536441 for ; Sun, 6 Nov 2022 09:47:23 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=iO1cqfEPvT4OVmbQuFvdxmx15ZvUmlKEEVGdTVAHkrL7a0HtwsDGY8ozMXtkZqUDO3iFfaNJb9ZCCU+PR0bZdhFYkdiP3ytCu+rcbHG2nmiwfi7n9BiUqEPtJg+CaaoNhLm1US81QDTJA3mzOMTEcq3JHtn7yLP0hXnhWZX6FJOYQXGb5TruWLbcyC3plx+pqxP0TvvoCU9kqGwwaAuAKFF0vZyicRL4oDIOgzqNUIjmB7HgUKwc9Tihqtx8zJV8eJ+S3U1WI+8qwNyHXHTIkZkPsgZSPXqOz88Mseo5Srd5B8xqtwCHe4xPYs2Y1O/ktyLbHeN3uyUIFKlbEWzOsA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=wn+CAXVEh+49LP4O9QRcHF/PKj2/uSGJRMg/oed3FYI=; b=VOoJDlXAkK6D17g56DPc4yn2iSNsyWowZMNyzNnUgkNFvWJ0pp4hOPub1BRjkED/euwEGttnOnQFBt9v5LEoRO+fv9c0Q7KYCbgonIT1NGm4kCaIuC48nRt9frgU2oGc2vL9RhUdgDEdVhoh8Xg9pXzFgVXKSxqtj9lnoTHahN4Cp9pyfTaxBgUq3yahFliQRnttproJrFZpFSj61neMrjhbFIpHsZjeUuyeLaI9pkLmBAiUxzERtym10uXWqrjQ2CSk8wUhZbSbxHKyazp/MotK+DzD+mUlRQxLLmKXXGLcZzsYNfrIB3AJm1kvHg3iiIFye95V57Xa5iwwhbXzBg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass (sender ip is 216.228.118.232) smtp.rcpttodomain=redhat.com smtp.mailfrom=nvidia.com; dmarc=pass (p=reject sp=reject pct=100) action=none header.from=nvidia.com; dkim=none (message not signed); arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=wn+CAXVEh+49LP4O9QRcHF/PKj2/uSGJRMg/oed3FYI=; b=jrvdgFf2wNiJCs7fhJSfRLDaiNMO8PXi+ER6CoVKeujAOmgS5VsdOPRtO45PwPnoU66RtNqx6h9C/LZF5S7mm6cRe/pFqeK36vA3E9CkNh+MwDr+YTn3A3wkWfIS9FZAG9lWt1KdLRaLA8nROnF4cZPRn3+R/IR9WhBXY1dat4w/4/PRV/J/viHjUBNXrfU6K5gGOQD75r+5jDorUZkA7gdEWFT1W+rLtMYyUfmTUhkhsgUaWhHUjO9Bo2+EAphvPmfZrSUAcWNsia+lRoXBbwB0wIS97i9PWQcMzYWvfYlk77AAF2DLCCdjw9trogVUOjVaexEY7zeNgioTDNCkMA== Received: from BN0PR03CA0007.namprd03.prod.outlook.com (2603:10b6:408:e6::12) by DS7PR12MB5816.namprd12.prod.outlook.com (2603:10b6:8:78::20) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5791.25; Sun, 6 Nov 2022 17:47:20 +0000 Received: from BN8NAM11FT057.eop-nam11.prod.protection.outlook.com (2603:10b6:408:e6:cafe::79) by BN0PR03CA0007.outlook.office365.com (2603:10b6:408:e6::12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5791.25 via Frontend Transport; Sun, 6 Nov 2022 17:47:20 +0000 X-MS-Exchange-Authentication-Results: spf=pass (sender IP is 216.228.118.232) smtp.mailfrom=nvidia.com; dkim=none (message not signed) header.d=none;dmarc=pass action=none header.from=nvidia.com; Received-SPF: Pass (protection.outlook.com: domain of nvidia.com designates 216.228.118.232 as permitted sender) receiver=protection.outlook.com; client-ip=216.228.118.232; helo=mail.nvidia.com; pr=C Received: from mail.nvidia.com (216.228.118.232) by BN8NAM11FT057.mail.protection.outlook.com (10.13.177.49) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5791.20 via Frontend Transport; Sun, 6 Nov 2022 17:47:20 +0000 Received: from drhqmail201.nvidia.com (10.126.190.180) by mail.nvidia.com (10.127.129.5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.26; Sun, 6 Nov 2022 09:47:19 -0800 Received: from drhqmail202.nvidia.com (10.126.190.181) by drhqmail201.nvidia.com (10.126.190.180) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.29; Sun, 6 Nov 2022 09:47:18 -0800 Received: from vdi.nvidia.com (10.127.8.10) by mail.nvidia.com (10.126.190.181) with Microsoft SMTP Server id 15.2.986.29 via Frontend Transport; Sun, 6 Nov 2022 09:47:16 -0800 From: Yishai Hadas To: , CC: , , , , , , , , Subject: [PATCH vfio 04/13] vfio: Extend the device migration protocol with PRE_COPY Date: Sun, 6 Nov 2022 19:46:21 +0200 Message-ID: <20221106174630.25909-5-yishaih@nvidia.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20221106174630.25909-1-yishaih@nvidia.com> References: <20221106174630.25909-1-yishaih@nvidia.com> MIME-Version: 1.0 X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BN8NAM11FT057:EE_|DS7PR12MB5816:EE_ X-MS-Office365-Filtering-Correlation-Id: 0d114f7b-5a6a-4173-567e-08dac01ef41b X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:216.228.118.232;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:mail.nvidia.com;PTR:dc7edge1.nvidia.com;CAT:NONE;SFS:(13230022)(4636009)(376002)(136003)(39860400002)(396003)(346002)(451199015)(36840700001)(40470700004)(46966006)(40480700001)(478600001)(30864003)(8936002)(5660300002)(36756003)(2906002)(316002)(6636002)(54906003)(110136005)(41300700001)(70586007)(70206006)(8676002)(4326008)(7636003)(83380400001)(356005)(36860700001)(82740400003)(7696005)(6666004)(86362001)(186003)(40460700003)(336012)(47076005)(426003)(1076003)(26005)(2616005)(82310400005);DIR:OUT;SFP:1101; X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 06 Nov 2022 17:47:20.0987 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 0d114f7b-5a6a-4173-567e-08dac01ef41b X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.118.232];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: BN8NAM11FT057.eop-nam11.prod.protection.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS7PR12MB5816 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Jason Gunthorpe The optional PRE_COPY states open the saving data transfer FD before reaching STOP_COPY and allows the device to dirty track internal state changes with the general idea to reduce the volume of data transferred in the STOP_COPY stage. While in PRE_COPY the device remains RUNNING, but the saving FD is open. Only if the device also supports RUNNING_P2P can it support PRE_COPY_P2P, which halts P2P transfers while continuing the saving FD. PRE_COPY, with P2P support, requires the driver to implement 7 new arcs and exists as an optional FSM branch between RUNNING and STOP_COPY: RUNNING -> PRE_COPY -> PRE_COPY_P2P -> STOP_COPY A new ioctl VFIO_MIG_GET_PRECOPY_INFO is provided to allow userspace to query the progress of the precopy operation in the driver with the idea it will judge to move to STOP_COPY at least once the initial data set is transferred, and possibly after the dirty size has shrunk appropriately. This ioctl is valid only in PRE_COPY states and kernel driver should return -EINVAL from any other migration state. Compared to the v1 clarification, STOP_COPY -> PRE_COPY is blocked and to be defined in future. We also split the pending_bytes report into the initial and sustaining values, e.g.: initial_bytes and dirty_bytes. initial_bytes: Amount of initial mandatory precopy data. dirty_bytes: device state changes relative to data previously retrieved. These fields are not required to have any bearing to STOP_COPY phase. Signed-off-by: Jason Gunthorpe Signed-off-by: Shay Drory Signed-off-by: Yishai Hadas --- drivers/vfio/vfio_main.c | 74 ++++++++++++++++++++++- include/uapi/linux/vfio.h | 122 ++++++++++++++++++++++++++++++++++++-- 2 files changed, 190 insertions(+), 6 deletions(-) diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c index b118e7b1bc59..c58a795510f9 100644 --- a/drivers/vfio/vfio_main.c +++ b/drivers/vfio/vfio_main.c @@ -1056,7 +1056,7 @@ int vfio_mig_get_next_state(struct vfio_device *device, enum vfio_device_mig_state new_fsm, enum vfio_device_mig_state *next_fsm) { - enum { VFIO_DEVICE_NUM_STATES = VFIO_DEVICE_STATE_RUNNING_P2P + 1 }; + enum { VFIO_DEVICE_NUM_STATES = VFIO_DEVICE_STATE_PRE_COPY_P2P + 1 }; /* * The coding in this table requires the driver to implement the * following FSM arcs: @@ -1071,30 +1071,65 @@ int vfio_mig_get_next_state(struct vfio_device *device, * RUNNING_P2P -> RUNNING * RUNNING_P2P -> STOP * STOP -> RUNNING_P2P - * Without P2P the driver must implement: + * + * If precopy is supported then the driver must support these additional + * FSM arcs: + * RUNNING -> PRE_COPY + * PRE_COPY -> RUNNING + * PRE_COPY -> STOP_COPY + * However, if precopy and P2P are supported together then the driver + * must support these additional arcs beyond the P2P arcs above: + * PRE_COPY -> RUNNING + * PRE_COPY -> PRE_COPY_P2P + * PRE_COPY_P2P -> PRE_COPY + * PRE_COPY_P2P -> RUNNING_P2P + * PRE_COPY_P2P -> STOP_COPY + * RUNNING -> PRE_COPY + * RUNNING_P2P -> PRE_COPY_P2P + * + * Without P2P and precopy the driver must implement: * RUNNING -> STOP * STOP -> RUNNING * * The coding will step through multiple states for some combination * transitions; if all optional features are supported, this means the * following ones: + * PRE_COPY -> PRE_COPY_P2P -> STOP_COPY + * PRE_COPY -> RUNNING -> RUNNING_P2P + * PRE_COPY -> RUNNING -> RUNNING_P2P -> STOP + * PRE_COPY -> RUNNING -> RUNNING_P2P -> STOP -> RESUMING + * PRE_COPY_P2P -> RUNNING_P2P -> RUNNING + * PRE_COPY_P2P -> RUNNING_P2P -> STOP + * PRE_COPY_P2P -> RUNNING_P2P -> STOP -> RESUMING * RESUMING -> STOP -> RUNNING_P2P + * RESUMING -> STOP -> RUNNING_P2P -> PRE_COPY_P2P * RESUMING -> STOP -> RUNNING_P2P -> RUNNING + * RESUMING -> STOP -> RUNNING_P2P -> RUNNING -> PRE_COPY * RESUMING -> STOP -> STOP_COPY + * RUNNING -> RUNNING_P2P -> PRE_COPY_P2P * RUNNING -> RUNNING_P2P -> STOP * RUNNING -> RUNNING_P2P -> STOP -> RESUMING * RUNNING -> RUNNING_P2P -> STOP -> STOP_COPY + * RUNNING_P2P -> RUNNING -> PRE_COPY * RUNNING_P2P -> STOP -> RESUMING * RUNNING_P2P -> STOP -> STOP_COPY + * STOP -> RUNNING_P2P -> PRE_COPY_P2P * STOP -> RUNNING_P2P -> RUNNING + * STOP -> RUNNING_P2P -> RUNNING -> PRE_COPY * STOP_COPY -> STOP -> RESUMING * STOP_COPY -> STOP -> RUNNING_P2P * STOP_COPY -> STOP -> RUNNING_P2P -> RUNNING + * + * The following transitions are blocked: + * STOP_COPY -> PRE_COPY + * STOP_COPY -> PRE_COPY_P2P */ static const u8 vfio_from_fsm_table[VFIO_DEVICE_NUM_STATES][VFIO_DEVICE_NUM_STATES] = { [VFIO_DEVICE_STATE_STOP] = { [VFIO_DEVICE_STATE_STOP] = VFIO_DEVICE_STATE_STOP, [VFIO_DEVICE_STATE_RUNNING] = VFIO_DEVICE_STATE_RUNNING_P2P, + [VFIO_DEVICE_STATE_PRE_COPY] = VFIO_DEVICE_STATE_RUNNING_P2P, + [VFIO_DEVICE_STATE_PRE_COPY_P2P] = VFIO_DEVICE_STATE_RUNNING_P2P, [VFIO_DEVICE_STATE_STOP_COPY] = VFIO_DEVICE_STATE_STOP_COPY, [VFIO_DEVICE_STATE_RESUMING] = VFIO_DEVICE_STATE_RESUMING, [VFIO_DEVICE_STATE_RUNNING_P2P] = VFIO_DEVICE_STATE_RUNNING_P2P, @@ -1103,14 +1138,38 @@ int vfio_mig_get_next_state(struct vfio_device *device, [VFIO_DEVICE_STATE_RUNNING] = { [VFIO_DEVICE_STATE_STOP] = VFIO_DEVICE_STATE_RUNNING_P2P, [VFIO_DEVICE_STATE_RUNNING] = VFIO_DEVICE_STATE_RUNNING, + [VFIO_DEVICE_STATE_PRE_COPY] = VFIO_DEVICE_STATE_PRE_COPY, + [VFIO_DEVICE_STATE_PRE_COPY_P2P] = VFIO_DEVICE_STATE_RUNNING_P2P, [VFIO_DEVICE_STATE_STOP_COPY] = VFIO_DEVICE_STATE_RUNNING_P2P, [VFIO_DEVICE_STATE_RESUMING] = VFIO_DEVICE_STATE_RUNNING_P2P, [VFIO_DEVICE_STATE_RUNNING_P2P] = VFIO_DEVICE_STATE_RUNNING_P2P, [VFIO_DEVICE_STATE_ERROR] = VFIO_DEVICE_STATE_ERROR, }, + [VFIO_DEVICE_STATE_PRE_COPY] = { + [VFIO_DEVICE_STATE_STOP] = VFIO_DEVICE_STATE_RUNNING, + [VFIO_DEVICE_STATE_RUNNING] = VFIO_DEVICE_STATE_RUNNING, + [VFIO_DEVICE_STATE_PRE_COPY] = VFIO_DEVICE_STATE_PRE_COPY, + [VFIO_DEVICE_STATE_PRE_COPY_P2P] = VFIO_DEVICE_STATE_PRE_COPY_P2P, + [VFIO_DEVICE_STATE_STOP_COPY] = VFIO_DEVICE_STATE_PRE_COPY_P2P, + [VFIO_DEVICE_STATE_RESUMING] = VFIO_DEVICE_STATE_RUNNING, + [VFIO_DEVICE_STATE_RUNNING_P2P] = VFIO_DEVICE_STATE_RUNNING, + [VFIO_DEVICE_STATE_ERROR] = VFIO_DEVICE_STATE_ERROR, + }, + [VFIO_DEVICE_STATE_PRE_COPY_P2P] = { + [VFIO_DEVICE_STATE_STOP] = VFIO_DEVICE_STATE_RUNNING_P2P, + [VFIO_DEVICE_STATE_RUNNING] = VFIO_DEVICE_STATE_RUNNING_P2P, + [VFIO_DEVICE_STATE_PRE_COPY] = VFIO_DEVICE_STATE_PRE_COPY, + [VFIO_DEVICE_STATE_PRE_COPY_P2P] = VFIO_DEVICE_STATE_PRE_COPY_P2P, + [VFIO_DEVICE_STATE_STOP_COPY] = VFIO_DEVICE_STATE_STOP_COPY, + [VFIO_DEVICE_STATE_RESUMING] = VFIO_DEVICE_STATE_RUNNING_P2P, + [VFIO_DEVICE_STATE_RUNNING_P2P] = VFIO_DEVICE_STATE_RUNNING_P2P, + [VFIO_DEVICE_STATE_ERROR] = VFIO_DEVICE_STATE_ERROR, + }, [VFIO_DEVICE_STATE_STOP_COPY] = { [VFIO_DEVICE_STATE_STOP] = VFIO_DEVICE_STATE_STOP, [VFIO_DEVICE_STATE_RUNNING] = VFIO_DEVICE_STATE_STOP, + [VFIO_DEVICE_STATE_PRE_COPY] = VFIO_DEVICE_STATE_ERROR, + [VFIO_DEVICE_STATE_PRE_COPY_P2P] = VFIO_DEVICE_STATE_ERROR, [VFIO_DEVICE_STATE_STOP_COPY] = VFIO_DEVICE_STATE_STOP_COPY, [VFIO_DEVICE_STATE_RESUMING] = VFIO_DEVICE_STATE_STOP, [VFIO_DEVICE_STATE_RUNNING_P2P] = VFIO_DEVICE_STATE_STOP, @@ -1119,6 +1178,8 @@ int vfio_mig_get_next_state(struct vfio_device *device, [VFIO_DEVICE_STATE_RESUMING] = { [VFIO_DEVICE_STATE_STOP] = VFIO_DEVICE_STATE_STOP, [VFIO_DEVICE_STATE_RUNNING] = VFIO_DEVICE_STATE_STOP, + [VFIO_DEVICE_STATE_PRE_COPY] = VFIO_DEVICE_STATE_STOP, + [VFIO_DEVICE_STATE_PRE_COPY_P2P] = VFIO_DEVICE_STATE_STOP, [VFIO_DEVICE_STATE_STOP_COPY] = VFIO_DEVICE_STATE_STOP, [VFIO_DEVICE_STATE_RESUMING] = VFIO_DEVICE_STATE_RESUMING, [VFIO_DEVICE_STATE_RUNNING_P2P] = VFIO_DEVICE_STATE_STOP, @@ -1127,6 +1188,8 @@ int vfio_mig_get_next_state(struct vfio_device *device, [VFIO_DEVICE_STATE_RUNNING_P2P] = { [VFIO_DEVICE_STATE_STOP] = VFIO_DEVICE_STATE_STOP, [VFIO_DEVICE_STATE_RUNNING] = VFIO_DEVICE_STATE_RUNNING, + [VFIO_DEVICE_STATE_PRE_COPY] = VFIO_DEVICE_STATE_RUNNING, + [VFIO_DEVICE_STATE_PRE_COPY_P2P] = VFIO_DEVICE_STATE_PRE_COPY_P2P, [VFIO_DEVICE_STATE_STOP_COPY] = VFIO_DEVICE_STATE_STOP, [VFIO_DEVICE_STATE_RESUMING] = VFIO_DEVICE_STATE_STOP, [VFIO_DEVICE_STATE_RUNNING_P2P] = VFIO_DEVICE_STATE_RUNNING_P2P, @@ -1135,6 +1198,8 @@ int vfio_mig_get_next_state(struct vfio_device *device, [VFIO_DEVICE_STATE_ERROR] = { [VFIO_DEVICE_STATE_STOP] = VFIO_DEVICE_STATE_ERROR, [VFIO_DEVICE_STATE_RUNNING] = VFIO_DEVICE_STATE_ERROR, + [VFIO_DEVICE_STATE_PRE_COPY] = VFIO_DEVICE_STATE_ERROR, + [VFIO_DEVICE_STATE_PRE_COPY_P2P] = VFIO_DEVICE_STATE_ERROR, [VFIO_DEVICE_STATE_STOP_COPY] = VFIO_DEVICE_STATE_ERROR, [VFIO_DEVICE_STATE_RESUMING] = VFIO_DEVICE_STATE_ERROR, [VFIO_DEVICE_STATE_RUNNING_P2P] = VFIO_DEVICE_STATE_ERROR, @@ -1145,6 +1210,11 @@ int vfio_mig_get_next_state(struct vfio_device *device, static const unsigned int state_flags_table[VFIO_DEVICE_NUM_STATES] = { [VFIO_DEVICE_STATE_STOP] = VFIO_MIGRATION_STOP_COPY, [VFIO_DEVICE_STATE_RUNNING] = VFIO_MIGRATION_STOP_COPY, + [VFIO_DEVICE_STATE_PRE_COPY] = + VFIO_MIGRATION_STOP_COPY | VFIO_MIGRATION_PRE_COPY, + [VFIO_DEVICE_STATE_PRE_COPY_P2P] = VFIO_MIGRATION_STOP_COPY | + VFIO_MIGRATION_P2P | + VFIO_MIGRATION_PRE_COPY, [VFIO_DEVICE_STATE_STOP_COPY] = VFIO_MIGRATION_STOP_COPY, [VFIO_DEVICE_STATE_RESUMING] = VFIO_MIGRATION_STOP_COPY, [VFIO_DEVICE_STATE_RUNNING_P2P] = diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h index 3e45dbaf190e..fca8e1b7e619 100644 --- a/include/uapi/linux/vfio.h +++ b/include/uapi/linux/vfio.h @@ -819,12 +819,20 @@ struct vfio_device_feature { * VFIO_MIGRATION_STOP_COPY | VFIO_MIGRATION_P2P means that RUNNING_P2P * is supported in addition to the STOP_COPY states. * + * VFIO_MIGRATION_STOP_COPY | VFIO_MIGRATION_PRE_COPY means that + * PRE_COPY is supported in addition to the STOP_COPY states. + * + * VFIO_MIGRATION_STOP_COPY | VFIO_MIGRATION_P2P | VFIO_MIGRATION_PRE_COPY + * means that RUNNING_P2P, PRE_COPY and PRE_COPY_P2P are supported + * in addition to the STOP_COPY states. + * * Other combinations of flags have behavior to be defined in the future. */ struct vfio_device_feature_migration { __aligned_u64 flags; #define VFIO_MIGRATION_STOP_COPY (1 << 0) #define VFIO_MIGRATION_P2P (1 << 1) +#define VFIO_MIGRATION_PRE_COPY (1 << 2) }; #define VFIO_DEVICE_FEATURE_MIGRATION 1 @@ -875,8 +883,13 @@ struct vfio_device_feature_mig_state { * RESUMING - The device is stopped and is loading a new internal state * ERROR - The device has failed and must be reset * - * And 1 optional state to support VFIO_MIGRATION_P2P: + * And optional states to support VFIO_MIGRATION_P2P: * RUNNING_P2P - RUNNING, except the device cannot do peer to peer DMA + * And VFIO_MIGRATION_PRE_COPY: + * PRE_COPY - The device is running normally but tracking internal state + * changes + * And VFIO_MIGRATION_P2P | VFIO_MIGRATION_PRE_COPY: + * PRE_COPY_P2P - PRE_COPY, except the device cannot do peer to peer DMA * * The FSM takes actions on the arcs between FSM states. The driver implements * the following behavior for the FSM arcs: @@ -908,20 +921,48 @@ struct vfio_device_feature_mig_state { * * To abort a RESUMING session the device must be reset. * + * PRE_COPY -> RUNNING * RUNNING_P2P -> RUNNING * While in RUNNING the device is fully operational, the device may generate * interrupts, DMA, respond to MMIO, all vfio device regions are functional, * and the device may advance its internal state. * + * The PRE_COPY arc will terminate a data transfer session. + * + * PRE_COPY_P2P -> RUNNING_P2P * RUNNING -> RUNNING_P2P * STOP -> RUNNING_P2P * While in RUNNING_P2P the device is partially running in the P2P quiescent * state defined below. * + * The PRE_COPY_P2P arc will terminate a data transfer session. + * + * RUNNING -> PRE_COPY + * RUNNING_P2P -> PRE_COPY_P2P * STOP -> STOP_COPY - * This arc begin the process of saving the device state and will return a - * new data_fd. + * PRE_COPY, PRE_COPY_P2P and STOP_COPY form the "saving group" of states + * which share a data transfer session. Moving between these states alters + * what is streamed in session, but does not terminate or otherwise affect + * the associated fd. + * + * These arcs begin the process of saving the device state and will return a + * new data_fd. The migration driver may perform actions such as enabling + * dirty logging of device state when entering PRE_COPY or PER_COPY_P2P. * + * Each arc does not change the device operation, the device remains + * RUNNING, P2P quiesced or in STOP. The STOP_COPY state is described below + * in PRE_COPY_P2P -> STOP_COPY. + * + * PRE_COPY -> PRE_COPY_P2P + * Entering PRE_COPY_P2P continues all the behaviors of PRE_COPY above. + * However, while in the PRE_COPY_P2P state, the device is partially running + * in the P2P quiescent state defined below, like RUNNING_P2P. + * + * PRE_COPY_P2P -> PRE_COPY + * This arc allows returning the device to a full RUNNING behavior while + * continuing all the behaviors of PRE_COPY. + * + * PRE_COPY_P2P -> STOP_COPY * While in the STOP_COPY state the device has the same behavior as STOP * with the addition that the data transfers session continues to stream the * migration state. End of stream on the FD indicates the entire device @@ -939,6 +980,13 @@ struct vfio_device_feature_mig_state { * device state for this arc if required to prepare the device to receive the * migration data. * + * STOP_COPY -> PRE_COPY + * STOP_COPY -> PRE_COPY_P2P + * These arcs are not permitted and return error if requested. Future + * revisions of this API may define behaviors for these arcs, in this case + * support will be discoverable by a new flag in + * VFIO_DEVICE_FEATURE_MIGRATION. + * * any -> ERROR * ERROR cannot be specified as a device state, however any transition request * can be failed with an errno return and may then move the device_state into @@ -950,7 +998,7 @@ struct vfio_device_feature_mig_state { * The optional peer to peer (P2P) quiescent state is intended to be a quiescent * state for the device for the purposes of managing multiple devices within a * user context where peer-to-peer DMA between devices may be active. The - * RUNNING_P2P states must prevent the device from initiating + * RUNNING_P2P and PRE_COPY_P2P states must prevent the device from initiating * any new P2P DMA transactions. If the device can identify P2P transactions * then it can stop only P2P DMA, otherwise it must stop all DMA. The migration * driver must complete any such outstanding operations prior to completing the @@ -963,6 +1011,8 @@ struct vfio_device_feature_mig_state { * above FSM arcs. As there are multiple paths through the FSM arcs the path * should be selected based on the following rules: * - Select the shortest path. + * - The path cannot have saving group states as interior arcs, only + * starting/end states. * Refer to vfio_mig_get_next_state() for the result of the algorithm. * * The automatic transit through the FSM arcs that make up the combination @@ -976,6 +1026,9 @@ struct vfio_device_feature_mig_state { * support them. The user can discover if these states are supported by using * VFIO_DEVICE_FEATURE_MIGRATION. By using combination transitions the user can * avoid knowing about these optional states if the kernel driver supports them. + * + * Arcs touching PRE_COPY and PRE_COPY_P2P are removed if support for PRE_COPY + * is not present. */ enum vfio_device_mig_state { VFIO_DEVICE_STATE_ERROR = 0, @@ -984,8 +1037,69 @@ enum vfio_device_mig_state { VFIO_DEVICE_STATE_STOP_COPY = 3, VFIO_DEVICE_STATE_RESUMING = 4, VFIO_DEVICE_STATE_RUNNING_P2P = 5, + VFIO_DEVICE_STATE_PRE_COPY = 6, + VFIO_DEVICE_STATE_PRE_COPY_P2P = 7, +}; + +/** + * VFIO_MIG_GET_PRECOPY_INFO - _IO(VFIO_TYPE, VFIO_BASE + 21) + * + * This ioctl is used on the migration data FD in the precopy phase of the + * migration data transfer. It returns an estimate of the current data sizes + * remaining to be transferred. It allows the user to judge when it is + * appropriate to leave PRE_COPY for STOP_COPY. + * + * This ioctl is valid only in PRE_COPY states and kernel driver should + * return -EINVAL from any other migration state. + * + * The vfio_precopy_info data structure returned by this ioctl provides + * estimates of data available from the device during the PRE_COPY states. + * This estimate is split into two categories, initial_bytes and + * dirty_bytes. + * + * The initial_bytes field indicates the amount of initial mandatory precopy + * data available from the device. This field should have a non-zero initial + * value and decrease as migration data is read from the device. + * It is a must to leave PRE_COPY for STOP_COPY only after this field reach + * zero. + * + * The dirty_bytes field tracks device state changes relative to data + * previously retrieved. This field starts at zero and may increase as + * the internal device state is modified or decrease as that modified + * state is read from the device. + * + * Userspace may use the combination of these fields to estimate the + * potential data size available during the PRE_COPY phases, as well as + * trends relative to the rate the device is dirtying its internal + * state, but these fields are not required to have any bearing relative + * to the data size available during the STOP_COPY phase. + * + * Drivers have a lot of flexibility in when and what they transfer during the + * PRE_COPY phase, and how they report this from VFIO_MIG_GET_PRECOPY_INFO. + * + * During pre-copy the migration data FD has a temporary "end of stream" that is + * reached when both initial_bytes and dirty_byte are zero. For instance, this + * may indicate that the device is idle and not currently dirtying any internal + * state. When read() is done on this temporary end of stream the kernel driver + * should return ENOMSG from read(). Userspace can wait for more data (which may + * never come) by using poll. + * + * Once in STOP_COPY the migration data FD has a permanent end of stream + * signaled in the usual way by read() always returning 0 and poll always + * returning readable. ENOMSG may not be returned in STOP_COPY. Support + * for this ioctl is optional. + * + * Return: 0 on success, -1 and errno set on failure. + */ +struct vfio_precopy_info { + __u32 argsz; + __u32 flags; + __aligned_u64 initial_bytes; + __aligned_u64 dirty_bytes; }; +#define VFIO_MIG_GET_PRECOPY_INFO _IO(VFIO_TYPE, VFIO_BASE + 21) + /* * Upon VFIO_DEVICE_FEATURE_SET, allow the device to be moved into a low power * state with the platform-based power management. Device use of lower power