From mboxrd@z Thu Jan 1 00:00:00 1970 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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 AA857C3A5A1 for ; Wed, 28 Aug 2019 14:55:37 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 3CB462189D for ; Wed, 28 Aug 2019 14:55:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3CB462189D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvmarm-bounces@lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id C0BA44A532; Wed, 28 Aug 2019 10:55:36 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id HxoY7rjdl1ei; Wed, 28 Aug 2019 10:55:34 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 4704C4A546; Wed, 28 Aug 2019 10:55:34 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 834794A533 for ; Wed, 28 Aug 2019 10:55:32 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id uykpLXiu8o-F for ; Wed, 28 Aug 2019 10:55:31 -0400 (EDT) Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id 857784A3A3 for ; Wed, 28 Aug 2019 10:55:31 -0400 (EDT) Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id AD05218C426B; Wed, 28 Aug 2019 14:55:30 +0000 (UTC) Received: from kamzik.brq.redhat.com (unknown [10.43.2.160]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 02ABB600CD; Wed, 28 Aug 2019 14:55:28 +0000 (UTC) Date: Wed, 28 Aug 2019 16:55:26 +0200 From: Andrew Jones To: Alexandru Elisei Subject: Re: [kvm-unit-tests RFC PATCH 08/16] lib: arm/arm64: Refuse to disable the MMU with non-identity stack pointer Message-ID: <20190828145526.g6xlotkhial5tv57@kamzik.brq.redhat.com> References: <1566999511-24916-1-git-send-email-alexandru.elisei@arm.com> <1566999511-24916-9-git-send-email-alexandru.elisei@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1566999511-24916-9-git-send-email-alexandru.elisei@arm.com> User-Agent: NeoMutt/20180716 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.62]); Wed, 28 Aug 2019 14:55:30 +0000 (UTC) Cc: kvm@vger.kernel.org, maz@kernel.org, andre.przywara@arm.com, pbonzini@redhat.com, kvmarm@lists.cs.columbia.edu X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu On Wed, Aug 28, 2019 at 02:38:23PM +0100, Alexandru Elisei wrote: > When the MMU is off, all addresses are physical addresses. If the stack > pointer is not an identity mapped address (the virtual address is not the > same as the physical address), then we end up trying to access an invalid > memory region. This can happen if we call mmu_disable from a secondary CPU, > which has its stack allocated from the vmalloc region. > > Signed-off-by: Alexandru Elisei > --- > lib/arm/mmu.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/lib/arm/mmu.c b/lib/arm/mmu.c > index 3d38c8397f5a..161f7a8e607c 100644 > --- a/lib/arm/mmu.c > +++ b/lib/arm/mmu.c > @@ -66,8 +66,12 @@ void mmu_enable(pgd_t *pgtable) > extern void asm_mmu_disable(void); > void mmu_disable(void) > { > + unsigned long sp = current_stack_pointer; > int cpu = current_thread_info()->cpu; > > + assert_msg(__virt_to_phys(sp) == sp, > + "Attempting to disable MMU with non-identity mapped stack"); > + > mmu_mark_disabled(cpu); > > asm_mmu_disable(); > -- > 2.7.4 > Reviewed-by: Andrew Jones _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm