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=-9.7 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_GIT 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 2C3CCC432C3 for ; Thu, 28 Nov 2019 18:04:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 06009217BC for ; Thu, 28 Nov 2019 18:04:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726957AbfK1SEw (ORCPT ); Thu, 28 Nov 2019 13:04:52 -0500 Received: from foss.arm.com ([217.140.110.172]:39422 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727086AbfK1SEt (ORCPT ); Thu, 28 Nov 2019 13:04:49 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A39761FB; Thu, 28 Nov 2019 10:04:49 -0800 (PST) Received: from e123195-lin.cambridge.arm.com (e123195-lin.cambridge.arm.com [10.1.196.63]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 80B433F6C4; Thu, 28 Nov 2019 10:04:48 -0800 (PST) From: Alexandru Elisei To: kvm@vger.kernel.org Cc: pbonzini@redhat.com, rkrcmar@redhat.com, drjones@redhat.com, maz@kernel.org, andre.przywara@arm.com, vladimir.murzin@arm.com, mark.rutland@arm.com Subject: [kvm-unit-tests PATCH v2 14/18] lib: arm/arm64: Refuse to disable the MMU with non-identity stack pointer Date: Thu, 28 Nov 2019 18:04:14 +0000 Message-Id: <20191128180418.6938-15-alexandru.elisei@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191128180418.6938-1-alexandru.elisei@arm.com> References: <20191128180418.6938-1-alexandru.elisei@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org 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. Reviewed-by: Andrew Jones 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 ed5411c157bb..773c764c4836 100644 --- a/lib/arm/mmu.c +++ b/lib/arm/mmu.c @@ -68,8 +68,12 @@ 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(); -- 2.20.1