From patchwork Mon Aug 13 14:57:20 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 10564317 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8324C14E2 for ; Mon, 13 Aug 2018 14:58:58 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 73B7329425 for ; Mon, 13 Aug 2018 14:58:58 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 681B929432; Mon, 13 Aug 2018 14:58:58 +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 0FA4329425 for ; Mon, 13 Aug 2018 14:58:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729241AbeHMRld (ORCPT ); Mon, 13 Aug 2018 13:41:33 -0400 Received: from foss.arm.com ([217.140.101.70]:59792 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729215AbeHMRlc (ORCPT ); Mon, 13 Aug 2018 13:41:32 -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 309E01596; Mon, 13 Aug 2018 07:58:56 -0700 (PDT) Received: from approximate.Emea.Arm.com (approximate.Emea.Arm.com [10.4.13.119]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 36AE03F5D0; Mon, 13 Aug 2018 07:58:53 -0700 (PDT) From: Marc Zyngier To: Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= Cc: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, Andre Przywara , Andrew Jones , Catalin Marinas , Christoffer Dall , Dongjiu Geng , Eric Auger , "Gustavo A . R . Silva" , James Morse , Jia He , Kees Cook , Mark Rutland , Punit Agrawal , Suzuki Poulose Subject: [PATCH 02/37] arm64: KVM: Handle Set/Way CMOs as NOPs if FWB is present Date: Mon, 13 Aug 2018 15:57:20 +0100 Message-Id: <20180813145755.16566-3-marc.zyngier@arm.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180813145755.16566-1-marc.zyngier@arm.com> References: <20180813145755.16566-1-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; }