From patchwork Mon Jul 2 15:02:46 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 10501779 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 5588E6028F for ; Mon, 2 Jul 2018 15:03:08 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4588F286F2 for ; Mon, 2 Jul 2018 15:03:08 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3A02028A6E; Mon, 2 Jul 2018 15:03:08 +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 D9B42286F2 for ; Mon, 2 Jul 2018 15:03:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752292AbeGBPDG (ORCPT ); Mon, 2 Jul 2018 11:03:06 -0400 Received: from foss.arm.com ([217.140.101.70]:34032 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752274AbeGBPDF (ORCPT ); Mon, 2 Jul 2018 11:03:05 -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 156C015AD; Mon, 2 Jul 2018 08:03:05 -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 B45A03F2EA; Mon, 2 Jul 2018 08:03:03 -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 , Mark Rutland , Suzuki K Poulose Subject: [PATCH v4 2/6] arm64: KVM: Handle Set/Way CMOs as NOPs if FWB is present Date: Mon, 2 Jul 2018 16:02:46 +0100 Message-Id: <20180702150250.16550-3-marc.zyngier@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180702150250.16550-1-marc.zyngier@arm.com> References: <20180702150250.16550-1-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 (the guest is forced to use cacheable memory, no matter what it says, and the whole system is garanteed to be cache coherent), 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. Reviewed-by: Christoffer Dall Signed-off-by: Marc Zyngier --- arch/arm64/kvm/sys_regs.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index a4363735d3f8..774d72155904 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -194,7 +194,16 @@ 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 (S/W operations should only + * be done by firmware, knowing that there is only a single + * CPU left in the system, and certainly not from non-secure + * software). + */ + if (!cpus_have_const_cap(ARM64_HAS_STAGE2_FWB)) + kvm_set_way_flush(vcpu); + return true; }