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: 10564323 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 2CFE814E2 for ; Mon, 13 Aug 2018 14:59:08 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1E05D2941C for ; Mon, 13 Aug 2018 14:59:08 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 11A1F2942A; Mon, 13 Aug 2018 14:59:08 +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=-2.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id B295A2941C for ; Mon, 13 Aug 2018 14:59:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=y3UeTOrWc/4zqpHRCuNRt23cClFtQ2fb/vPMq/kCqTA=; b=ur9MSPTx7RjL2kqKhecM9/9Gsh FxUd7KwcesdnlMxuPAj9Ogu1pKtYgRg/jQhjkE5HFi622/f14tX/0D9RToTmsXElFJ0IpqW1ZZ0GM +hpUlLEiP54cd0hj/935ekG60/QsPsC6Gc+s414t9i8EPvJoF+dWmxY/npexJM2LeqH/UzJcKDjwU jWkqEtjPdUGKjNw79/zGaMaqfAphr3OVTfgz3XGe1LLSyRxhZoOkRYYK8ji1AeN3WEdRKbzbRBjvS R5VdoeLwfe5WhqolVNbZF10RpqihzpFAQJKWHsA7VxgI5GQ+g0XpLCDDVTeIoIMLPP0daAdaL9dol Iafu3qCw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1fpEJE-0005PO-FS; Mon, 13 Aug 2018 14:59:04 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1fpEJA-0005NJ-V3 for linux-arm-kernel@lists.infradead.org; Mon, 13 Aug 2018 14:59:02 +0000 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?= 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> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20180813_075901_018328_0D439B4B X-CRM114-Status: GOOD ( 14.37 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Andrew Jones , Kees Cook , kvm@vger.kernel.org, "Gustavo A . R . Silva" , Andre Przywara , Punit Agrawal , Christoffer Dall , Dongjiu Geng , Jia He , Eric Auger , James Morse , Catalin Marinas , Suzuki Poulose , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.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; }