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=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 DEE60C433E2 for ; Fri, 11 Sep 2020 13:28:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 96B8222251 for ; Fri, 11 Sep 2020 13:28:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599830904; bh=Ck6R26J1uh6Rx8WttW2mXHHMdiQg0iuI2zMfWNWohzE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=gC+g2bnEn3qD6/k5JVc5QmXuraveb8jep8gPJqIc8K874ZGcQJ5rrJCL9lN4+nRcx e0PHmbLtr6n+2LjUhTg6K8eolTUZnzDxazPb6f4u3nsC1UBD3SF/x1rq9bnakmEirL U0BTcPHDpEcowPUugQUuSmCKMgG1nylWZeiEgETU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726295AbgIKN2V (ORCPT ); Fri, 11 Sep 2020 09:28:21 -0400 Received: from mail.kernel.org ([198.145.29.99]:54394 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726196AbgIKNFo (ORCPT ); Fri, 11 Sep 2020 09:05:44 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E6ABC22204; Fri, 11 Sep 2020 12:57:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599829072; bh=Ck6R26J1uh6Rx8WttW2mXHHMdiQg0iuI2zMfWNWohzE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=h0I4YvmYoockp/XpZmGwNq5vyBJ6OuhtHcTYMo/OD/OSVF7U/BxIDT9k0elnrp9Ze rOqFroGO4myp0EXmwiia1OPLI1HyLgHOgTEybCGae22DqJ0OVoIpfA7NvCGojzS3av MCq/pXjvC2uSxpJliwqeqZmykc0UZYdDulHjvyHU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , James Morse , Marc Zyngier , Catalin Marinas , Andre Przywara Subject: [PATCH 4.9 55/71] KVM: arm64: Set HCR_EL2.PTW to prevent AT taking synchronous exception Date: Fri, 11 Sep 2020 14:46:39 +0200 Message-Id: <20200911122507.657997515@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200911122504.928931589@linuxfoundation.org> References: <20200911122504.928931589@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: James Morse commit 71a7f8cb1ca4ca7214a700b1243626759b6c11d4 upstream. AT instructions do a translation table walk and return the result, or the fault in PAR_EL1. KVM uses these to find the IPA when the value is not provided by the CPU in HPFAR_EL1. If a translation table walk causes an external abort it is taken as an exception, even if it was due to an AT instruction. (DDI0487F.a's D5.2.11 "Synchronous faults generated by address translation instructions") While we previously made KVM resilient to exceptions taken due to AT instructions, the device access causes mismatched attributes, and may occur speculatively. Prevent this, by forbidding a walk through memory described as device at stage2. Now such AT instructions will report a stage2 fault. Such a fault will cause KVM to restart the guest. If the AT instructions always walk the page tables, but guest execution uses the translation cached in the TLB, the guest can't make forward progress until the TLB entry is evicted. This isn't a problem, as since commit 5dcd0fdbb492 ("KVM: arm64: Defer guest entry when an asynchronous exception is pending"), KVM will return to the host to process IRQs allowing the rest of the system to keep running. Cc: stable@vger.kernel.org # v4.9 Signed-off-by: James Morse Reviewed-by: Marc Zyngier Signed-off-by: Catalin Marinas Signed-off-by: Andre Przywara Signed-off-by: Greg Kroah-Hartman --- arch/arm64/include/asm/kvm_arm.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/arch/arm64/include/asm/kvm_arm.h +++ b/arch/arm64/include/asm/kvm_arm.h @@ -78,10 +78,11 @@ * IMO: Override CPSR.I and enable signaling with VI * FMO: Override CPSR.F and enable signaling with VF * SWIO: Turn set/way invalidates into set/way clean+invalidate + * PTW: Take a stage2 fault if a stage1 walk steps in device memory */ #define HCR_GUEST_FLAGS (HCR_TSC | HCR_TSW | HCR_TWE | HCR_TWI | HCR_VM | \ HCR_TVM | HCR_BSU_IS | HCR_FB | HCR_TAC | \ - HCR_AMO | HCR_SWIO | HCR_TIDCP | HCR_RW) + HCR_AMO | HCR_SWIO | HCR_TIDCP | HCR_RW | HCR_PTW) #define HCR_VIRT_EXCP_MASK (HCR_VSE | HCR_VI | HCR_VF) #define HCR_INT_OVERRIDE (HCR_FMO | HCR_IMO) #define HCR_HOST_NVHE_FLAGS (HCR_RW | HCR_API | HCR_APK)