From patchwork Wed Sep 22 10:38:51 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Leon Romanovsky X-Patchwork-Id: 12510189 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-20.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9E1CAC433EF for ; Wed, 22 Sep 2021 10:39:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8566A61211 for ; Wed, 22 Sep 2021 10:39:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234936AbhIVKkf (ORCPT ); Wed, 22 Sep 2021 06:40:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:48610 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234734AbhIVKke (ORCPT ); Wed, 22 Sep 2021 06:40:34 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 476D261242; Wed, 22 Sep 2021 10:39:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1632307145; bh=BcqOr4/BxckdG0JgeNfJQFTFky8MX/TUfOd14KVupMg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NO7+DDQKkUHe7MiF7RQT1bVBXOL2lYpqKp+0Ducw833CAOcSDD17RVIKO1Xlcmhha qAK7XZgWeoTr0t3Sw0vnaMW+1qy9SG1EalylI50ryXMVFLn48PfrJIzysTvtIXI3Yd edP8Z3l6ZdORIuDJ/c4Ae8J9Bxf7D9w8mZw8Hk3YUteyd76r6z7Q7MIedjHjGI1hZ/ KLNrcE8hCecIMtLEQYa5EAnj+NFB0Hl6Z7isQQT+2t6HppHdJmrb34STPrgi7Q2JpH VxId5zhQyJLVystRl10Avj5WSMlmNPPwywY1/Od0m2dasU3bldr3ownauJ4LQyUoor Vn/oZBE7cmBtQ== From: Leon Romanovsky To: Doug Ledford , Jason Gunthorpe Cc: Yishai Hadas , Alex Williamson , Bjorn Helgaas , "David S. Miller" , Jakub Kicinski , Kirti Wankhede , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-rdma@vger.kernel.org, netdev@vger.kernel.org, Saeed Mahameed Subject: [PATCH mlx5-next 2/7] vfio: Add an API to check migration state transition validity Date: Wed, 22 Sep 2021 13:38:51 +0300 Message-Id: X-Mailer: git-send-email 2.31.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org From: Yishai Hadas Add an API in the core layer to check migration state transition validity as part of a migration flow. The valid transitions follow the expected usage as described in uapi/vfio.h and triggered by QEMU. This ensures that all migration implementations follow a consistent migration state machine. Signed-off-by: Yishai Hadas Reviewed-by: Kirti Wankhede Signed-off-by: Jason Gunthorpe Signed-off-by: Leon Romanovsky --- drivers/vfio/vfio.c | 41 +++++++++++++++++++++++++++++++++++++++++ include/linux/vfio.h | 1 + 2 files changed, 42 insertions(+) diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index 3c034fe14ccb..c3ca33e513c8 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -1664,6 +1664,47 @@ static int vfio_device_fops_release(struct inode *inode, struct file *filep) return 0; } +/** + * vfio_change_migration_state_allowed - Checks whether a migration state + * transition is valid. + * @new_state: The new state to move to. + * @old_state: The old state. + * Return: true if the transition is valid. + */ +bool vfio_change_migration_state_allowed(u32 new_state, u32 old_state) +{ + enum { MAX_STATE = VFIO_DEVICE_STATE_RESUMING }; + static const u8 vfio_from_state_table[MAX_STATE + 1][MAX_STATE + 1] = { + [VFIO_DEVICE_STATE_STOP] = { + [VFIO_DEVICE_STATE_RUNNING] = 1, + [VFIO_DEVICE_STATE_RESUMING] = 1, + }, + [VFIO_DEVICE_STATE_RUNNING] = { + [VFIO_DEVICE_STATE_STOP] = 1, + [VFIO_DEVICE_STATE_SAVING] = 1, + [VFIO_DEVICE_STATE_SAVING | VFIO_DEVICE_STATE_RUNNING] = 1, + }, + [VFIO_DEVICE_STATE_SAVING] = { + [VFIO_DEVICE_STATE_STOP] = 1, + [VFIO_DEVICE_STATE_RUNNING] = 1, + }, + [VFIO_DEVICE_STATE_SAVING | VFIO_DEVICE_STATE_RUNNING] = { + [VFIO_DEVICE_STATE_RUNNING] = 1, + [VFIO_DEVICE_STATE_SAVING] = 1, + }, + [VFIO_DEVICE_STATE_RESUMING] = { + [VFIO_DEVICE_STATE_RUNNING] = 1, + [VFIO_DEVICE_STATE_STOP] = 1, + }, + }; + + if (new_state > MAX_STATE || old_state > MAX_STATE) + return false; + + return vfio_from_state_table[old_state][new_state]; +} +EXPORT_SYMBOL_GPL(vfio_change_migration_state_allowed); + static long vfio_device_fops_unl_ioctl(struct file *filep, unsigned int cmd, unsigned long arg) { diff --git a/include/linux/vfio.h b/include/linux/vfio.h index b53a9557884a..e65137a708f1 100644 --- a/include/linux/vfio.h +++ b/include/linux/vfio.h @@ -83,6 +83,7 @@ extern struct vfio_device *vfio_device_get_from_dev(struct device *dev); extern void vfio_device_put(struct vfio_device *device); int vfio_assign_device_set(struct vfio_device *device, void *set_id); +bool vfio_change_migration_state_allowed(u32 new_state, u32 old_state); /* events for the backend driver notify callback */ enum vfio_iommu_notify_type {