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: 69458 Received: from vger.kernel.org ([23.128.96.18]) by www.linuxtv.org with esmtp (Exim 4.92) (envelope-from ) id 1kigqC-00Cqiq-4I; Fri, 27 Nov 2020 16:43:24 +0000 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731981AbgK0Qme (ORCPT + 1 other); Fri, 27 Nov 2020 11:42:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54092 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731906AbgK0QmU (ORCPT ); Fri, 27 Nov 2020 11:42:20 -0500 Received: from mail-wr1-x443.google.com (mail-wr1-x443.google.com [IPv6:2a00:1450:4864:20::443]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 06CB6C061A48 for ; Fri, 27 Nov 2020 08:42:19 -0800 (PST) Received: by mail-wr1-x443.google.com with SMTP id e7so6207471wrv.6 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=n3MGVJfuoLo0ViN0KQ1zHioi/2r1xpHUqcMajovacstWaa20wwMqFDdGRk/3UfDYzP o7xCcSNr/tmibs50fN45XErlOWesEQvNrbRsScfCOTRyhKTdunbciPLKopsXBvB0Es20 n6I50AOREgVkNyEFAt8obidU2qonFE8+usRvHQbA7kXKZNXWefidgHZLOEYSN60RUSOI +8wOj7kcgKXW36RbYXPLAQKXxPlnhdcVA8H1kIj29PTOQHtTIMdMIL5pwULWBU0wjYAZ JAYglEO+gQPyJl8v+1hfq8lWtDVopunwDKhjgKgjWejqSh/33y6TiuvNgSVE6AQSc9Iy xIXw== X-Gm-Message-State: AOAM5326Q7xXSSljanaN65FWCUb9LPyoCcwnsbjkAd14Ot8UfkPs5GO3 WSvwUcmU9+/YNAOXTO+kASsJhQ== 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: linux-media@vger.kernel.org X-LSpam-Score: -2.5 (--) X-LSpam-Report: No, score=-2.5 required=5.0 tests=BAYES_00=-1.9,DKIM_SIGNED=0.1,DKIM_VALID=-0.1,DKIM_VALID_AU=-0.1,HEADER_FROM_DIFFERENT_DOMAINS=0.5,MAILING_LIST_MULTI=-1 autolearn=ham autolearn_force=no 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;