From patchwork Thu Nov 19 14:41:39 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Daniel Vetter X-Patchwork-Id: 11917811 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=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 8795DC6379D for ; Thu, 19 Nov 2020 14:44:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 31B0D22253 for ; Thu, 19 Nov 2020 14:44:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="lhtA9EHT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728424AbgKSOn0 (ORCPT ); Thu, 19 Nov 2020 09:43:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37436 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728285AbgKSOmK (ORCPT ); Thu, 19 Nov 2020 09:42:10 -0500 Received: from mail-wm1-x342.google.com (mail-wm1-x342.google.com [IPv6:2a00:1450:4864:20::342]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 38168C061A4A for ; Thu, 19 Nov 2020 06:42:08 -0800 (PST) Received: by mail-wm1-x342.google.com with SMTP id c9so7419277wml.5 for ; Thu, 19 Nov 2020 06:42:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=r9CpIi9VXsG+zuZeNFc6wtzpnBA/KWk/gpfUTZT1Zjk=; b=lhtA9EHTSs14S/lWfBd1cIy0B+1WAFjZ2wwrxe0xfxaPFoO4tE/BV8FsM/+QBdNKSb qaDof6bo+sV1dmoR3pr9L3cROFnjeyDX7YUhLjLaTr5vvJuZGC/AQ8qhGDGYOPWuK2ES DXV+m9I+q0gCIequCxlA9xJnLLr4u+Z/5Mgjs= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=r9CpIi9VXsG+zuZeNFc6wtzpnBA/KWk/gpfUTZT1Zjk=; b=f3N88gA6sqZ+8eyLQ9d15L8NkAn9hnq5BZd5kOzzmfylc/BUjHNkTp2etdSM1j/1z9 9zTZHLypmKaPDTo5wSQWpHLvxHWAz3Ykwuwx2bWFizVDm9BC/ut34wbVtlIw0c+J50Wf Hy/EPeVnuoh9aG8uL52LcJ/u8WXjMKeTOsHcJV2XmD9BqcKlcXScxqnyFe8JfCNg/FiZ 5KuwGhs2oPjojkyHc4YTbSpZlhWoa3NnmA9GwmIybrzLMDdfARtFc9wLp+JzDzrxnQmR DI1vDlWt2xkC+wd/MIbyVXY1JSeyce+ARHFFtGdz4jgYpxVbMHkVpB4S3K8ET6hhmtjC UmdA== X-Gm-Message-State: AOAM5329PsKZBZMIIH8nNWHgV0e+PqMwRzrhYp4UvvR3Om2Rg80oCjMZ LEBWevQUPiOjXFbYnyF5XGAI/w== X-Google-Smtp-Source: ABdhPJwmTNYcq6djsIakV7SIgJh96B+fhnfkl7M76m7WAG1RYZMmoYFSDpdjObIHYtpegBgvRnmxPg== X-Received: by 2002:a05:600c:288:: with SMTP id 8mr4943834wmk.106.1605796926931; Thu, 19 Nov 2020 06:42:06 -0800 (PST) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id x63sm51292wmb.48.2020.11.19.06.42.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 19 Nov 2020 06:42:06 -0800 (PST) From: Daniel Vetter To: DRI Development , LKML Cc: kvm@vger.kernel.org, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-media@vger.kernel.org, Daniel Vetter , Daniel Vetter , Jason Gunthorpe , Kees Cook , Dan Williams , Andrew Morton , John Hubbard , =?utf-8?b?SsOpcsO0bWUgR2xpc3Nl?= , Jan Kara , Alex Williamson , Cornelia Huck Subject: [PATCH v6 10/17] vfio/type1: Mark follow_pfn as unsafe Date: Thu, 19 Nov 2020 15:41:39 +0100 Message-Id: <20201119144146.1045202-11-daniel.vetter@ffwll.ch> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201119144146.1045202-1-daniel.vetter@ffwll.ch> References: <20201119144146.1045202-1-daniel.vetter@ffwll.ch> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org The code seems to stuff these pfns into iommu pts (or something like that, I didn't follow), but there's no mmu_notifier to ensure that access is synchronized with pte updates. Hence mark these as unsafe. This means that with CONFIG_STRICT_FOLLOW_PFN, these will be rejected. Real fix is to wire up an mmu_notifier ... somehow. Probably means any invalidate is a fatal fault for this vfio device, but then this shouldn't ever happen if userspace is reasonable. Signed-off-by: Daniel Vetter Cc: Jason Gunthorpe Cc: Kees Cook Cc: Dan Williams Cc: Andrew Morton Cc: John Hubbard Cc: Jérôme Glisse Cc: Jan Kara Cc: Dan Williams Cc: linux-mm@kvack.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-samsung-soc@vger.kernel.org Cc: linux-media@vger.kernel.org Cc: Alex Williamson Cc: Cornelia Huck Cc: kvm@vger.kernel.org Signed-off-by: Daniel Vetter --- drivers/vfio/vfio_iommu_type1.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index 67e827638995..10170723bb58 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -421,7 +421,7 @@ static int follow_fault_pfn(struct vm_area_struct *vma, struct mm_struct *mm, { int ret; - ret = follow_pfn(vma, vaddr, pfn); + ret = unsafe_follow_pfn(vma, vaddr, pfn); if (ret) { bool unlocked = false; @@ -435,7 +435,7 @@ static int follow_fault_pfn(struct vm_area_struct *vma, struct mm_struct *mm, if (ret) return ret; - ret = follow_pfn(vma, vaddr, pfn); + ret = unsafe_follow_pfn(vma, vaddr, pfn); } return ret;