From patchwork Thu May 17 10:35:48 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 10406293 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 449EB60155 for ; Thu, 17 May 2018 10:36:20 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3391128A5A for ; Thu, 17 May 2018 10:36:20 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 26A9528A5D; Thu, 17 May 2018 10:36:20 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C438C28A5A for ; Thu, 17 May 2018 10:36:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752186AbeEQKgR (ORCPT ); Thu, 17 May 2018 06:36:17 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:33376 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751478AbeEQKgO (ORCPT ); Thu, 17 May 2018 06:36:14 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 00557165C; Thu, 17 May 2018 03:36:14 -0700 (PDT) Received: from approximate.cambridge.arm.com (approximate.cambridge.arm.com [10.1.206.75]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E73663F25D; Thu, 17 May 2018 03:36:12 -0700 (PDT) From: Marc Zyngier To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Cc: Christoffer Dall , Catalin Marinas Subject: [PATCH 4/4] arm64: KVM: Handle Set/Way CMOs as NOPs if FWB is present Date: Thu, 17 May 2018 11:35:48 +0100 Message-Id: <20180517103548.5622-5-marc.zyngier@arm.com> X-Mailer: git-send-email 2.14.2 In-Reply-To: <20180517103548.5622-1-marc.zyngier@arm.com> References: <20180517103548.5622-1-marc.zyngier@arm.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Set/Way handling is one of the ugliest corners of KVM. We shouldn't have to handle that, but better safe than sorry. Thankfully, FWB fixes this for us by not requiering any maintenance whatsoever, which means we don't have to emulate S/W CMOs, and don't have to track VM ops either. We still have to trap S/W though, if only to prevent the guest from doing something bad. Signed-off-by: Marc Zyngier --- arch/arm64/kvm/sys_regs.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 806b0b126a64..ef373963bf95 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -195,7 +195,13 @@ static bool access_dcsw(struct kvm_vcpu *vcpu, if (!p->is_write) return read_from_write_only(vcpu, p, r); - kvm_set_way_flush(vcpu); + /* + * Only track S/W ops if we don't have FWB. It still indicates + * that the guest is a bit broken... + */ + if (!cpus_have_const_cap(ARM64_HAS_STAGE2_FWB)) + kvm_set_way_flush(vcpu); + return true; }