From patchwork Mon Oct 26 10:58:13 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Daniel Vetter X-Patchwork-Id: 11856529 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 1C8E9921 for ; Mon, 26 Oct 2020 10:59:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 010FF2225C for ; Mon, 26 Oct 2020 10:59:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="Cr+pmJXJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1772957AbgJZK7h (ORCPT ); Mon, 26 Oct 2020 06:59:37 -0400 Received: from mail-wm1-f66.google.com ([209.85.128.66]:53064 "EHLO mail-wm1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1772804AbgJZK6l (ORCPT ); Mon, 26 Oct 2020 06:58:41 -0400 Received: by mail-wm1-f66.google.com with SMTP id c194so11152243wme.2 for ; Mon, 26 Oct 2020 03:58:40 -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=hp7lChw6Uow+58XPniSHemIeAoNErbB/sdK6im80Iug=; b=Cr+pmJXJLsWocfKRIRa/5RHLA7hSR2O/V8a+9H+OfOBLfntuyYXq0XvJAi9z0VTfHT o6muhLbGVgMDDFHz7pi7g0wbMI0xim0wkiLglb6gq1U7avKTlbLZaGt6brXdeBhZPYiG 7tcXzotmBBEhyDhg4r894G/MEQ31CzKNdntL0= 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=hp7lChw6Uow+58XPniSHemIeAoNErbB/sdK6im80Iug=; b=uSg/krxXj2iT/zQ30OpbuSmBMKj9VOxy1WRwqob9YRpyStooIkQkFY0NdUfarnCtqq Yze4Ja5wPTOkGwKM8YUg/kgzQti4eu/pz8yxBNIeWvaVme6GFIssmPyonnGZr+lUkXbv /soOwvW2ZnZKeUl4rplVst2GD6JsVGLnvoCMfumUuX6lXA0ZQfN/31LFmDCTHnirsOkq xJHLbZJqiy+8UXIo/3KgZRtFrrVu0iwUB7hgYI20OqqhDNSgn4QV/tj0J2JZSqSw5cag dYazrfdWftLFim7DIRCeoEEIBpCERSrern4zW6sxuvgiXmgFwvXE8LJ0kgjMWRlu+chw DIzA== X-Gm-Message-State: AOAM532AYFvsasstI8D055S8E3PPqNSQxdyELYaCdzv0/N6LL4p12b/H ciJRHafcbdb5w56C4LuB+5yVaQ== X-Google-Smtp-Source: ABdhPJyXE1xnVL9rMrbjHo2QW8UsY5WSv6Qb5ykdefmn1P9qttdIUjS9wMyJqMVtlrB26EUB1SiNdg== X-Received: by 2002:a05:600c:25a:: with SMTP id 26mr14957501wmj.39.1603709919599; Mon, 26 Oct 2020 03:58:39 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id w83sm21165156wmg.48.2020.10.26.03.58.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 26 Oct 2020 03:58:38 -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 v4 10/15] vfio/type1: Mark follow_pfn as unsafe Date: Mon, 26 Oct 2020 11:58:13 +0100 Message-Id: <20201026105818.2585306-11-daniel.vetter@ffwll.ch> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201026105818.2585306-1-daniel.vetter@ffwll.ch> References: <20201026105818.2585306-1-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 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;