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=-17.5 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,URIBL_BLOCKED autolearn=unavailable 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 676B7C433F5 for ; Thu, 23 Sep 2021 11:17:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4D8AA61214 for ; Thu, 23 Sep 2021 11:17:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240565AbhIWLSy (ORCPT ); Thu, 23 Sep 2021 07:18:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:36866 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240493AbhIWLSy (ORCPT ); Thu, 23 Sep 2021 07:18:54 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2566760EC0; Thu, 23 Sep 2021 11:17:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1632395842; bh=zKKSudppIjrRqr4TCmMFfzY41RyPZoIxc16LkmrNL/U=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=oGeyDLaX4lQGPaOi+ovJOGnARXuHikewcOJiJ3hcTJg+HCmlpKK1hZtk193nKXj4g VYu/lY3gBmp7kNdJui6EMFwTnpeYXgpuv0Bl+Y07GxUpVyxMBmGsSamPafWauMYP+k fqIh+VPDyu99HwV8vYMFOxlzjCs3iTdnatfa4xqRM8qSHWFfJaxrNeyFzV5OoA0D// POBzO/pushbYCHybc5JuG8dkHMipLBXOF6zYLttGANC2mQuh6OAygYDuVRmVU86wpm PuJj+caSmaVs+3Cs1WwJVmh3D/6t2pwj7pg7iw6BN4tNxHcGkmdJetP0VtBzM0XO1s pHvTXnMKMiWyw== Date: Thu, 23 Sep 2021 14:17:18 +0300 From: Leon Romanovsky To: Shameerali Kolothum Thodi Cc: Doug Ledford , Jason Gunthorpe , 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 Message-ID: References: <42729adc4df649f7b3ce5dc95e66e2dc@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <42729adc4df649f7b3ce5dc95e66e2dc@huawei.com> Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Thu, Sep 23, 2021 at 10:33:10AM +0000, Shameerali Kolothum Thodi wrote: > > > > -----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, It looks like we missed this state transition. Thanks > > " * 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 >