From mboxrd@z Thu Jan 1 00:00:00 1970 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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 DF893C433EF for ; Thu, 23 Sep 2021 10:33:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C3C3661164 for ; Thu, 23 Sep 2021 10:33:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240331AbhIWKeo convert rfc822-to-8bit (ORCPT ); Thu, 23 Sep 2021 06:34:44 -0400 Received: from frasgout.his.huawei.com ([185.176.79.56]:3852 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231392AbhIWKeo (ORCPT ); Thu, 23 Sep 2021 06:34:44 -0400 Received: from fraeml713-chm.china.huawei.com (unknown [172.18.147.206]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4HFWdw4R79z67bWP; Thu, 23 Sep 2021 18:30:44 +0800 (CST) Received: from lhreml717-chm.china.huawei.com (10.201.108.68) by fraeml713-chm.china.huawei.com (10.206.15.32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.8; Thu, 23 Sep 2021 12:33:10 +0200 Received: from lhreml710-chm.china.huawei.com (10.201.108.61) by lhreml717-chm.china.huawei.com (10.201.108.68) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.8; Thu, 23 Sep 2021 11:33:10 +0100 Received: from lhreml710-chm.china.huawei.com ([169.254.81.184]) by lhreml710-chm.china.huawei.com ([169.254.81.184]) with mapi id 15.01.2308.008; Thu, 23 Sep 2021 11:33:10 +0100 From: Shameerali Kolothum Thodi To: Leon Romanovsky , 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: RE: [PATCH mlx5-next 2/7] vfio: Add an API to check migration state transition validity Thread-Topic: [PATCH mlx5-next 2/7] vfio: Add an API to check migration state transition validity Thread-Index: AQHXr54pt96rmXk0YUaXSN2Kf89+2auxakgA Date: Thu, 23 Sep 2021 10:33:10 +0000 Message-ID: <42729adc4df649f7b3ce5dc95e66e2dc@huawei.com> References: In-Reply-To: Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.47.85.235] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org > -----Original Message----- > From: Leon Romanovsky [mailto:leon@kernel.org] > Sent: 22 September 2021 11:39 > 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 > > 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, Do we need to allow _RESUMING state here or not? As per the "State transitions" section from uapi/linux/vfio.h, " * 4. To start the resuming phase, the device state should be transitioned from * the _RUNNING to the _RESUMING state." IIRC, I have seen that transition happening on the destination dev while testing the HiSilicon ACC dev migration. Thanks, Shameer > + }, > + [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 { > -- > 2.31.1