From patchwork Thu Aug 26 13:34:15 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 12459869 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=-16.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 99E07C432BE for ; Thu, 26 Aug 2021 13:41:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7B91060E73 for ; Thu, 26 Aug 2021 13:41:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242745AbhHZNm1 (ORCPT ); Thu, 26 Aug 2021 09:42:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49024 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242712AbhHZNm1 (ORCPT ); Thu, 26 Aug 2021 09:42:27 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D4BA1C061757 for ; Thu, 26 Aug 2021 06:41:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=+5pcR9shTFpIoryoVzMQ1haWJAZEzLk7xrUKnLWneaU=; b=mx48KhCIa67B1IjB+6Du85ZJeE 6xCadWsnGdUXzQOr1RqHCYQh1cFJ2U4FL/VfQtQhb+d0vw5EzvfghZDEigWUiALMInsdqypmUJJWX tCUJlxTGFLYYRsIwJuovv87vPAp5y+ncP4CWH0SylN5PdxJ4/AJqTrOmGf6gcT2+UEr4s1ZPrFrxg oCC7KffVcgnrpJyb9VXsYww2/7iNXrRp3bZLcJQDCz8fVfh+6syJ3XYaYRCMjahCBffdIcf+FDxCF 73iiQcJ7s8svW69PNc8NpMdLuLSz+CJowS1hcCUlYJ51nadDIPbDLC/TpoKcyu65+QWGgZisOyq8t 1tN1GSWw==; Received: from [2001:4bb8:193:fd10:d9d9:6c15:481b:99c4] (helo=localhost) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1mJFbG-00DL87-Rg; Thu, 26 Aug 2021 13:39:53 +0000 From: Christoph Hellwig To: Alex Williamson Cc: Diana Craciun , Cornelia Huck , Kirti Wankhede , Eric Auger , Jason Gunthorpe , kvm@vger.kernel.org, Jason Gunthorpe Subject: [PATCH 05/14] vfio: refactor noiommu group creation Date: Thu, 26 Aug 2021 15:34:15 +0200 Message-Id: <20210826133424.3362-6-hch@lst.de> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210826133424.3362-1-hch@lst.de> References: <20210826133424.3362-1-hch@lst.de> MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Split the actual noiommu group creation from vfio_iommu_group_get into a new helper, and open code the rest of vfio_iommu_group_get in its only caller. This creates an entirely separate and clear code path for the noiommu group creation. Signed-off-by: Christoph Hellwig Reviewed-by: Jason Gunthorpe --- drivers/vfio/vfio.c | 101 ++++++++++++++++++++++---------------------- 1 file changed, 51 insertions(+), 50 deletions(-) diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index 852fe22125520d..109d3ef57665b0 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -169,50 +169,6 @@ static void vfio_release_device_set(struct vfio_device *device) xa_unlock(&vfio_device_set_xa); } -static struct iommu_group *vfio_iommu_group_get(struct device *dev) -{ - struct iommu_group *group; - int __maybe_unused ret; - - group = iommu_group_get(dev); - -#ifdef CONFIG_VFIO_NOIOMMU - /* - * With noiommu enabled, an IOMMU group will be created for a device - * that doesn't already have one and doesn't have an iommu_ops on their - * bus. We set iommudata simply to be able to identify these groups - * as special use and for reclamation later. - */ - if (group || !noiommu || iommu_present(dev->bus)) - return group; - - group = iommu_group_alloc(); - if (IS_ERR(group)) - return NULL; - - iommu_group_set_name(group, "vfio-noiommu"); - iommu_group_set_iommudata(group, &noiommu, NULL); - ret = iommu_group_add_device(group, dev); - if (ret) { - iommu_group_put(group); - return NULL; - } - - /* - * Where to taint? At this point we've added an IOMMU group for a - * device that is not backed by iommu_ops, therefore any iommu_ - * callback using iommu_ops can legitimately Oops. So, while we may - * be about to give a DMA capable device to a user without IOMMU - * protection, which is clearly taint-worthy, let's go ahead and do - * it here. - */ - add_taint(TAINT_USER, LOCKDEP_STILL_OK); - dev_warn(dev, "Adding kernel taint for vfio-noiommu group on device\n"); -#endif - - return group; -} - #ifdef CONFIG_VFIO_NOIOMMU static void *vfio_noiommu_open(unsigned long arg) { @@ -823,12 +779,61 @@ void vfio_uninit_group_dev(struct vfio_device *device) } EXPORT_SYMBOL_GPL(vfio_uninit_group_dev); -struct vfio_group *vfio_group_find_or_alloc(struct device *dev) +#ifdef CONFIG_VFIO_NOIOMMU +static struct vfio_group *vfio_noiommu_group_alloc(struct device *dev) { struct iommu_group *iommu_group; struct vfio_group *group; + int ret; + + iommu_group = iommu_group_alloc(); + if (IS_ERR(iommu_group)) + return ERR_CAST(iommu_group); - iommu_group = vfio_iommu_group_get(dev); + iommu_group_set_name(iommu_group, "vfio-noiommu"); + iommu_group_set_iommudata(iommu_group, &noiommu, NULL); + ret = iommu_group_add_device(iommu_group, dev); + if (ret) + goto out_put_group; + + group = vfio_create_group(iommu_group); + if (IS_ERR(group)) { + ret = PTR_ERR(group); + goto out_remove_device; + } + + return group; + +out_remove_device: + iommu_group_remove_device(dev); +out_put_group: + iommu_group_put(iommu_group); + return ERR_PTR(ret); +} +#endif + +static struct vfio_group *vfio_group_find_or_alloc(struct device *dev) +{ + struct iommu_group *iommu_group; + struct vfio_group *group; + + iommu_group = iommu_group_get(dev); +#ifdef CONFIG_VFIO_NOIOMMU + if (!iommu_group && noiommu && !iommu_present(dev->bus)) { + /* + * With noiommu enabled, create an IOMMU group for devices that + * don't already have one and don't have an iommu_ops on their + * bus. Taint the kernel because we're about to give a DMA + * capable device to a user without IOMMU protection. + */ + group = vfio_noiommu_group_alloc(dev); + if (group) { + add_taint(TAINT_USER, LOCKDEP_STILL_OK); + dev_warn(dev, "Adding kernel taint for vfio-noiommu group on device\n"); + } + return group; + } +#endif if (!iommu_group) return ERR_PTR(-EINVAL); @@ -844,10 +849,6 @@ struct vfio_group *vfio_group_find_or_alloc(struct device *dev) return group; out_put: -#ifdef CONFIG_VFIO_NOIOMMU - if (iommu_group_get_iommudata(iommu_group) == &noiommu) - iommu_group_remove_device(dev); -#endif iommu_group_put(iommu_group); return group; }