From patchwork Fri Nov 27 16:41:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Daniel Vetter X-Patchwork-Id: 11936801 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=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 06747C8301F for ; Fri, 27 Nov 2020 16:43:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C1E10206DF for ; Fri, 27 Nov 2020 16:43:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="QYSE9aht" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731972AbgK0QmY (ORCPT ); Fri, 27 Nov 2020 11:42:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54098 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731915AbgK0QmV (ORCPT ); Fri, 27 Nov 2020 11:42:21 -0500 Received: from mail-wr1-x444.google.com (mail-wr1-x444.google.com [IPv6:2a00:1450:4864:20::444]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 08C02C061A51 for ; Fri, 27 Nov 2020 08:42:19 -0800 (PST) Received: by mail-wr1-x444.google.com with SMTP id m6so6195296wrg.7 for ; Fri, 27 Nov 2020 08:42:18 -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=QYSE9ahtLKl5EGqlS1wxqny1lcMayoTshiQPV4fpDlmhPBNcviZXZr4Hw/D0VvV1nZ SlhSkjL1LPH6m8vp1Ns0BA38yTfYlhhdthl3ANf0Zfah59++5CuB09/jCSZWOACnz6YY w3HN6kMl99DtY/VTvVNMApS0itb5pUGMEw+wM= 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=V04GzDzPzRV2iy77hrQXm0vzDvb33iuXw5nK9CIVBbId/12k33u/KNQu8LdXXFAs81 ueh9sn4mMfNV+OhnVsvIIMtmIE1NnSgIO86c8H1lucA2yrEMCdjiWf4hSzsTotgmAZH/ B1NeA40JfR5FOH67bMmM37gcC+47jk+9U7B7m4oOy8PqrQcSgSzx58oYXjUCEsrQyX89 m3Qv1r9QgPeJ/khvY9CMOv/e+lcGf+ysOU6W0Rb//17qoMxEWdVVnkW/Tja8vriDLXir wj9cDjm+kPceVbsQ7EmS1frU0j6XxHXLtO8eRp2t0mepej6dT4XOYKvrDQm0Fg2eo4gm acdA== X-Gm-Message-State: AOAM5333Mv38wJSAyhD1nOglD3jwToGkBWtwG85MZwW6409iHBIm/BNM 8LfuI+wM1fmEfxOFWJS9Dda67g== X-Google-Smtp-Source: ABdhPJwcuwkwTEGjFtq/EaV85N+PVRZBWU4U/IYqc96jNDCQ+Wh7QXU+d6PyrzBG7/osel2wfk3tIQ== X-Received: by 2002:a5d:5651:: with SMTP id j17mr11831109wrw.221.1606495337823; Fri, 27 Nov 2020 08:42:17 -0800 (PST) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id q12sm14859078wrx.86.2020.11.27.08.42.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 27 Nov 2020 08:42:17 -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 v7 15/17] vfio/type1: Mark follow_pfn as unsafe Date: Fri, 27 Nov 2020 17:41:29 +0100 Message-Id: <20201127164131.2244124-16-daniel.vetter@ffwll.ch> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201127164131.2244124-1-daniel.vetter@ffwll.ch> References: <20201127164131.2244124-1-daniel.vetter@ffwll.ch> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@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;