From patchwork Wed Oct 7 16:44:26 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Daniel Vetter X-Patchwork-Id: 11821151 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 6FE0814D5 for ; Wed, 7 Oct 2020 16:45:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 49FBA2087D for ; Wed, 7 Oct 2020 16:45:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="a2SgXBBU" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728719AbgJGQpO (ORCPT ); Wed, 7 Oct 2020 12:45:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52752 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728151AbgJGQpK (ORCPT ); Wed, 7 Oct 2020 12:45:10 -0400 Received: from mail-wm1-x344.google.com (mail-wm1-x344.google.com [IPv6:2a00:1450:4864:20::344]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1EF4FC0613AE for ; Wed, 7 Oct 2020 09:44:53 -0700 (PDT) Received: by mail-wm1-x344.google.com with SMTP id d81so3056060wmc.1 for ; Wed, 07 Oct 2020 09:44:53 -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=a2SgXBBUMUv5rmGUViyhFF3lXGILq+ogZQ2bnU5yTikNVO1UZPKFkXR+cMKdD1Rm41 5hVocxtJ1ruQTjzYF+j/kcPmUrlEoxcZlfmxmNQGpyMtXOQYmsEC5x5GfoD+TsHChPd5 kBGdx5zpKgy7OHc0eDbqjMmuhQ+fylwUh0bkY= 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=Oje42w4f81hcU2KH7sbsKHAlpQlw3Z4vk7gocvvhB3TCVBMGn+W52qZ11/UXGmfivp P7PQH8VLEMxGRHWHetvczedqRLKseL8inIruJ8ObniGG98KHD1UtQZDxNdbxn6iO3rp8 bXQQtQc4AaeDbAsyr8FKhdFAkfWA2TasLHI/ZeLFV0RbYMsqEkYS9GDsjZHnfc787+ov jEiQEqzNeikJG19hcqpSIGI8tiykMxad4wKgSBK2ZXMLxUIZskuCvYzQFQaFB8dExDkz 0NVAJj2aPWjBEVgh1iFSWmrqjEKbTWFMm94VHJjrGb/kzuhpAw2/1RJ18SLlVtC/UvjO mq3g== X-Gm-Message-State: AOAM531eEUoQH8jpqUdSk//4sBPn8wZdpTVunzR0Z7BjCq3H5M3eHQYE 1CxWmdT1qrIHtxWDyDkxYkKJBg== X-Google-Smtp-Source: ABdhPJyl2kosXxLomdssAdbm1Dfrg8OGKCCvnST/uKNr1+7zqiZZaytFpiBFyLEYCms+wEDhkOE1tw== X-Received: by 2002:a1c:5a05:: with SMTP id o5mr4000978wmb.7.1602089091831; Wed, 07 Oct 2020 09:44:51 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id z191sm3332280wme.40.2020.10.07.09.44.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 07 Oct 2020 09:44:51 -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 13/13] vfio/type1: Mark follow_pfn as unsafe Date: Wed, 7 Oct 2020 18:44:26 +0200 Message-Id: <20201007164426.1812530-14-daniel.vetter@ffwll.ch> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201007164426.1812530-1-daniel.vetter@ffwll.ch> References: <20201007164426.1812530-1-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;