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=-4.0 required=3.0 tests=BAYES_00,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 5E530C07E9B for ; Wed, 21 Jul 2021 08:23:09 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id C53C56120D for ; Wed, 21 Jul 2021 08:23:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C53C56120D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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 648E64B117; Wed, 21 Jul 2021 04:23:08 -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 RHUkJakRtTAa; Wed, 21 Jul 2021 04:23:07 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 517914B11E; Wed, 21 Jul 2021 04:23:07 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id EB2DA4B117 for ; Wed, 21 Jul 2021 04:23:05 -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 Z8BpiOCUs3fN for ; Wed, 21 Jul 2021 04:23:04 -0400 (EDT) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id 082ED4B112 for ; Wed, 21 Jul 2021 04:23:04 -0400 (EDT) Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 46F786120A; Wed, 21 Jul 2021 08:23:02 +0000 (UTC) Received: from sofa.misterjones.org ([185.219.108.64] helo=why.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1m67VM-00Eev3-8O; Wed, 21 Jul 2021 09:23:00 +0100 Date: Wed, 21 Jul 2021 09:22:44 +0100 Message-ID: <87im142i0b.wl-maz@kernel.org> From: Marc Zyngier To: Sergey Senozhatsky Subject: Re: [PATCHv2 2/4] arm64: add guest pvstate support In-Reply-To: References: <20210709043713.887098-1-senozhatsky@chromium.org> <20210709043713.887098-3-senozhatsky@chromium.org> <877dhv35ea.wl-maz@kernel.org> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/27.1 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: senozhatsky@chromium.org, will@kernel.org, suleiman@google.com, joelaf@google.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Cc: Joel Fernandes , linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, Suleiman Souhlal , 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 Wed, 21 Jul 2021 03:05:25 +0100, Sergey Senozhatsky wrote: > > On (21/07/12 16:42), Marc Zyngier wrote: > > > > > > PV-vcpu-state is a per-CPU struct, which, for the time being, > > > holds boolean `preempted' vCPU state. During the startup, > > > given that host supports PV-state, each guest vCPU sends > > > a pointer to its per-CPU variable to the host as a payload > > > > What is the expected memory type for this memory region? What is its > > life cycle? Where is it allocated from? > > Guest per-CPU area, which physical addresses is shared with the > host. Again: what are the memory types you expect this to be used with? When will the hypervisor ever stop accessing this? How does it work across reset? I'm sorry to be that pressing, but these are the gory details that actually matter if you want this thing to be maintainable. Thanks, M. -- Without deviation from the norm, progress is not possible. _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm