From patchwork Fri Sep 4 13:30:01 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 310125 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=-10.0 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=unavailable 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 BC45AC2BB84 for ; Fri, 4 Sep 2020 14:21:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 81E0D20797 for ; Fri, 4 Sep 2020 14:21:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599229299; bh=TFnCzz/oxl1Z9g3HmDAlM7mLxYJEGSfxJEqQhLnHhfE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=BRqyQLQkvCE97wTcu08scIODW1BOSzKm1cTDdTJuyRRkUyWiBWX/ZfofchAQGmJlk HBQR8cNIfrOruMTvsUjSvOekPWHbL3p+VLTAMwZMru9yWt0k5CBA1KgYw2XVc8sY3k piW1Ghrfv5Lhq4zAdlaE2czJKpZK9XPIBV7qyWGI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730415AbgIDOVg (ORCPT ); Fri, 4 Sep 2020 10:21:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:43444 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730395AbgIDNlu (ORCPT ); Fri, 4 Sep 2020 09:41:50 -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 F1192208C7; Fri, 4 Sep 2020 13:30:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599226210; bh=TFnCzz/oxl1Z9g3HmDAlM7mLxYJEGSfxJEqQhLnHhfE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=P/ZcULZo5H4VT4/zgjRSHf5X4Y+z/Sy+CVto82I7Bnq6rTtkJsL8k34i0gcTjaTDW tIdtzqAVf0EfcesZomWvN72k3hKdY6W6ol0eLNWeJn3yvSsVAE2fe4kZOVQf+Wir1G t3MwkAygRZhKmDbuwbnXM7IjoIn+62f5ScJXEIV8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, James Morse , Marc Zyngier , Catalin Marinas , Andre Przywara Subject: [PATCH 5.4 08/16] KVM: arm64: Set HCR_EL2.PTW to prevent AT taking synchronous exception Date: Fri, 4 Sep 2020 15:30:01 +0200 Message-Id: <20200904120257.605755537@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200904120257.203708503@linuxfoundation.org> References: <20200904120257.203708503@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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 # 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 @@ -72,11 +72,12 @@ * 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_TLOR | \ - HCR_FMO | HCR_IMO) + HCR_FMO | HCR_IMO | HCR_PTW ) #define HCR_VIRT_EXCP_MASK (HCR_VSE | HCR_VI | HCR_VF) #define HCR_HOST_NVHE_FLAGS (HCR_RW | HCR_API | HCR_APK) #define HCR_HOST_VHE_FLAGS (HCR_RW | HCR_TGE | HCR_E2H)