From mboxrd@z Thu Jan 1 00:00:00 1970 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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham 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 C937CCA9EBC for ; Fri, 25 Oct 2019 15:57:18 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 5961221E6F for ; Fri, 25 Oct 2019 15:57:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5961221E6F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvmarm-bounces@lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id CB5344A53F; Fri, 25 Oct 2019 11:57:17 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id LbR4bGIyYNAT; Fri, 25 Oct 2019 11:57:16 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id B80534A4FC; Fri, 25 Oct 2019 11:57:16 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id E72F94A3B4 for ; Fri, 25 Oct 2019 11:57:14 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id dPOwwXt0EMYv for ; Fri, 25 Oct 2019 11:57:13 -0400 (EDT) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by mm01.cs.columbia.edu (Postfix) with ESMTP id D8CD14A389 for ; Fri, 25 Oct 2019 11:57:13 -0400 (EDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5C30B328; Fri, 25 Oct 2019 08:57:13 -0700 (PDT) Received: from C02TF0J2HF1T.local (C02TF0J2HF1T.cambridge.arm.com [10.1.26.186]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 78F003F71A; Fri, 25 Oct 2019 08:57:10 -0700 (PDT) Date: Fri, 25 Oct 2019 16:57:08 +0100 From: Catalin Marinas To: Steven Price Subject: Re: [PATCH v7 10/10] arm64: Retrieve stolen time as paravirtualized guest Message-ID: <20191025155708.GB999@C02TF0J2HF1T.local> References: <20191021152823.14882-1-steven.price@arm.com> <20191021152823.14882-11-steven.price@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20191021152823.14882-11-steven.price@arm.com> User-Agent: Mutt/1.12.1 (2019-06-15) Cc: kvm@vger.kernel.org, Marc Zyngier , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Russell King , Paolo Bonzini , Will Deacon , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu On Mon, Oct 21, 2019 at 04:28:23PM +0100, Steven Price wrote: > Enable paravirtualization features when running under a hypervisor > supporting the PV_TIME_ST hypercall. > > For each (v)CPU, we ask the hypervisor for the location of a shared > page which the hypervisor will use to report stolen time to us. We set > pv_time_ops to the stolen time function which simply reads the stolen > value from the shared page for a VCPU. We guarantee single-copy > atomicity using READ_ONCE which means we can also read the stolen > time for another VCPU than the currently running one while it is > potentially being updated by the hypervisor. > > Signed-off-by: Steven Price Acked-by: Catalin Marinas _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm