From patchwork Fri Oct 9 07:59:28 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Daniel Vetter X-Patchwork-Id: 11825197 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 7CAC917D1 for ; Fri, 9 Oct 2020 08:00:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 51706222C2 for ; Fri, 9 Oct 2020 08:00:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="D1VJi6UD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732736AbgJIIAO (ORCPT ); Fri, 9 Oct 2020 04:00:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49540 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732738AbgJIIAN (ORCPT ); Fri, 9 Oct 2020 04:00:13 -0400 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 6311DC0604C0 for ; Fri, 9 Oct 2020 01:00:09 -0700 (PDT) Received: by mail-wr1-x444.google.com with SMTP id i1so3122886wro.1 for ; Fri, 09 Oct 2020 01:00:09 -0700 (PDT) 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=le1GUptU9JjBH114uU563JmUcYegKwYn9xh0zAQdRv8=; b=D1VJi6UDBiQk2hO8dFve4gh+DKwL/4hvYIL5H14t+/WkC6EkC0QuzB+xVNaIVhimgb u3J/6YYVnKsy9E3ATy/UWE+cLNXaPddTma9scUgc+w9imr71cIasK3qOPcYgE9YB/pK2 huXf9HsnQzVH0icRGFbigbp5CUz+XW5pf1/tI= 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=le1GUptU9JjBH114uU563JmUcYegKwYn9xh0zAQdRv8=; b=GdqLJEWruyPG15K7xMg/I+WyEJDHjeHpMV/Yv7SjN+uIwkNnXzMhX5V64E4/9/QZyu 2/F/080INqij29mBvV4KHUa7dTwQb5j+g2WBDEeAEb4tD0vHCP1//MioYQvGqFHvQ1P4 ja1zlPNLZOhuKSLKOS1LDBya4xf+MOYZAPB6wQNwxPjjiDGYQMytIP9SfVPFY8PYb9En SGhHZj+XiRJZFW0MDvNYcFK1DzS/maHZvGVvuWX9CRg9h0Xnnwk5iABnKcWHXpeipAja DubM5KLMgZQbZFxZNCgP6Nb9sihGrTZ9NtHeQX9fgPOiHF/IescW6JyGGYsFZuXPs9vy UoLQ== X-Gm-Message-State: AOAM530gSZl9tXa8Zl27gPlLlRylHmgcwJ6RlfXHcZDz+R+O4IULHJhk FXMzbXQa65YkfIw3vQX/WVseuA== X-Google-Smtp-Source: ABdhPJz4MKP5KGohAdR58eqqZNbRUjATksd5quRpBzCsMu6hT8STZxdOkUvTUNe8EYXb+jIiohIVBA== X-Received: by 2002:adf:bc14:: with SMTP id s20mr14299261wrg.220.1602230408064; Fri, 09 Oct 2020 01:00:08 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id u17sm11634118wri.45.2020.10.09.01.00.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 09 Oct 2020 01:00:07 -0700 (PDT) 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, linux-s390@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 v2 11/17] vfio/type1: Mark follow_pfn as unsafe Date: Fri, 9 Oct 2020 09:59:28 +0200 Message-Id: <20201009075934.3509076-12-daniel.vetter@ffwll.ch> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201009075934.3509076-1-daniel.vetter@ffwll.ch> References: <20201009075934.3509076-1-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 --- 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 5fbf0c1f7433..a4d53f3d0a35 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;