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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 3071FC4332B for ; Fri, 20 Mar 2020 18:34:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 01A852072C for ; Fri, 20 Mar 2020 18:34:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="gDPJeP35" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727129AbgCTSeb (ORCPT ); Fri, 20 Mar 2020 14:34:31 -0400 Received: from us-smtp-delivery-74.mimecast.com ([216.205.24.74]:58837 "EHLO us-smtp-delivery-74.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726783AbgCTSeb (ORCPT ); Fri, 20 Mar 2020 14:34:31 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1584729269; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=y0Np0CarGBUbN7siKQ/jnSvkwfPUS2q7/dKzjlzIzSk=; b=gDPJeP35XH+1nM3TumcQ7jAUTeTyz0adMp9XixloxNfU4JSogzJ1daqsDMi9qMgfpjMcI+ o7zeUuNmrfUTPp83z6BDqSntE7TH3VEFAGAS4bO5pR+TZpfOQ7zZD5Bb7o5VzOEB0xMiGG Gz0AmByQE+o7ttuBwkJho6nPzdki4MU= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-429-A2lGiqZvP1aGsscMkHDWpQ-1; Fri, 20 Mar 2020 14:34:28 -0400 X-MC-Unique: A2lGiqZvP1aGsscMkHDWpQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C0CFF101FC64; Fri, 20 Mar 2020 18:34:26 +0000 (UTC) Received: from w520.home (ovpn-112-162.phx2.redhat.com [10.3.112.162]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4A2A45C3FD; Fri, 20 Mar 2020 18:34:26 +0000 (UTC) Date: Fri, 20 Mar 2020 12:34:25 -0600 From: Alex Williamson To: Yonghyun Hwang Cc: Kirti Wankhede , Cornelia Huck , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Havard Skinnemoen , Moritz Fischer Subject: Re: [PATCH] vfio-mdev: support mediated device creation in kernel Message-ID: <20200320123425.49c6568e@w520.home> In-Reply-To: <20200320175910.180266-1-yonghyun@google.com> References: <20200320175910.180266-1-yonghyun@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 20 Mar 2020 10:59:10 -0700 Yonghyun Hwang wrote: > To enable a mediated device, a device driver registers its device to VFIO > MDev framework. Once the mediated device gets enabled, UUID gets fed onto > the sysfs attribute, "create", to create the mediated device. This > additional step happens after boot-up gets complete. If the driver knows > how many mediated devices need to be created during probing time, the > additional step becomes cumbersome. This commit implements a new function > to allow the driver to create a mediated device in kernel. But pre-creating mdev devices seems like a policy decision. Why can't userspace make such a policy decision, and do so with persistent uuids, via something like mdevctl? Thanks, Alex > Signed-off-by: Yonghyun Hwang > --- > drivers/vfio/mdev/mdev_core.c | 45 +++++++++++++++++++++++++++++++++++ > include/linux/mdev.h | 3 +++ > 2 files changed, 48 insertions(+) > > diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c > index b558d4cfd082..a6d32516de42 100644 > --- a/drivers/vfio/mdev/mdev_core.c > +++ b/drivers/vfio/mdev/mdev_core.c > @@ -350,6 +350,51 @@ int mdev_device_create(struct kobject *kobj, > return ret; > } > > +/* > + * mdev_create_device : Create a mdev device > + * @dev: device structure representing parent device. > + * @uuid: uuid char string for a mdev device. > + * @group: index to supported type groups for a mdev device. > + * > + * Create a mdev device in kernel. > + * Returns a negative value on error, otherwise 0. > + */ > +int mdev_create_device(struct device *dev, > + const char *uuid, int group) > +{ > + struct mdev_parent *parent = NULL; > + struct mdev_type *type = NULL; > + guid_t guid; > + int i = 1; > + int ret; > + > + ret = guid_parse(uuid, &guid); > + if (ret) { > + dev_err(dev, "Failed to parse UUID"); > + return ret; > + } > + > + parent = __find_parent_device(dev); > + if (!parent) { > + dev_err(dev, "Failed to find parent mdev device"); > + return -ENODEV; > + } > + > + list_for_each_entry(type, &parent->type_list, next) { > + if (i == group) > + break; > + i++; > + } > + > + if (!type || i != group) { > + dev_err(dev, "Failed to find mdev device"); > + return -ENODEV; > + } > + > + return mdev_device_create(&type->kobj, parent->dev, &guid); > +} > +EXPORT_SYMBOL(mdev_create_device); > + > int mdev_device_remove(struct device *dev) > { > struct mdev_device *mdev, *tmp; > diff --git a/include/linux/mdev.h b/include/linux/mdev.h > index 0ce30ca78db0..b66f67998916 100644 > --- a/include/linux/mdev.h > +++ b/include/linux/mdev.h > @@ -145,4 +145,7 @@ struct device *mdev_parent_dev(struct mdev_device *mdev); > struct device *mdev_dev(struct mdev_device *mdev); > struct mdev_device *mdev_from_dev(struct device *dev); > > +extern int mdev_create_device(struct device *dev, > + const char *uuid, int group_idx); > + > #endif /* MDEV_H */