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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 74F30C678D4 for ; Fri, 3 Mar 2023 12:20:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To:Subject: MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=3eQU1e/JFZq6JWU0fnnc1x1l77RJhPVqip9BBA7snGY=; b=EB1VbMnRqrwl55 j1+3pwB+i4Rl4kXxBr5UcoVXgosM3r4kE6glzTlw0+37SiowMrCx8TqJl7OYG+piQN0zXFGKe3U1Y vmNOErtIC6juK+fue9rVhmQ+DTyy0nFPyF9Svr6LuOlvntqCyJext97zTVCjc8ZE/YulDuNAZ65i5 9ZxFo+Jle6bk4D+NapulLL9+RL2pChnKH/L3pMO7SHvSa5wEF59NF7LdHc5P1dQo7X0mW3IF5dSOE XSkldLwICIPVfjEpXNVLghhlfhA5IQDldz1NFLCTa+nt4tCkLDqb3tVVhXZIJ31Nir2rgLuXectPK CtSvWX4iAVNnF5lJcF9Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pY4OH-006IWW-Is; Fri, 03 Mar 2023 12:20:01 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pY4OE-006IV9-Au for linux-arm-kernel@lists.infradead.org; Fri, 03 Mar 2023 12:19:59 +0000 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 C2FE42F4; Fri, 3 Mar 2023 04:20:34 -0800 (PST) Received: from [10.57.90.45] (unknown [10.57.90.45]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id A77B93F93E; Fri, 3 Mar 2023 04:19:47 -0800 (PST) Message-ID: <2418536c-2658-18d6-f70c-c1af5adaa816@arm.com> Date: Fri, 3 Mar 2023 12:19:46 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.7.2 Subject: Re: [RFC] Support for Arm CCA VMs on Linux To: Andrew Jones , Jean-Philippe Brucker Cc: Jean-Philippe Brucker , Itaru Kitayama , linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, Alexandru Elisei , Catalin Marinas , Chao Peng , Christoffer Dall , Fuad Tabba , James Morse , Joey Gouly , Marc Zyngier , Mark Rutland , Oliver Upton , Paolo Bonzini , Quentin Perret , Sean Christopherson , Steven Price , Thomas Huth , Will Deacon , Zenghui Yu , kvmarm@lists.cs.columbia.edu References: <20230127112248.136810-1-suzuki.poulose@arm.com> <20230303094618.GC361458@myrica> <1c91b777-982e-e71a-4829-51744e9555c5@arm.com> <20230303113905.GD361458@myrica> <20230303120800.ahtyc6et77ig4s27@orel> From: Suzuki K Poulose In-Reply-To: <20230303120800.ahtyc6et77ig4s27@orel> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230303_041958_522881_1F66A1C9 X-CRM114-Status: GOOD ( 16.73 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 03/03/2023 12:08, Andrew Jones wrote: > On Fri, Mar 03, 2023 at 11:39:05AM +0000, Jean-Philippe Brucker wrote: >> On Fri, Mar 03, 2023 at 09:54:47AM +0000, Suzuki K Poulose wrote: >>> On 03/03/2023 09:46, Jean-Philippe Brucker wrote: >>>> On Thu, Mar 02, 2023 at 07:12:24AM +0900, Itaru Kitayama wrote: >>>>>>> I've tried your series in Real on CCA Host, but the KVM arch init >>>>>>> emits an Invalid argument error and terminates. >>>> >>>> This was the KVM_SET_ONE_REG for the SVE vector size. During my tests I >>>> didn't enable SVE in the host but shrinkwrap enables more options. >>> >>> Does the Qemu check for SVE capability on /dev/kvm ? For kvmtool, we >>> changed to using the VM instance and that would prevent using SVE, >>> until the RMM supports it. >> >> Yes, QEMU does check the SVE cap on /dev/kvm. I can propose changing it or >> complementing it with a VM check in my next version, it seems to work >> (though I need to double-check the VM fd lifetime). Same goes for >> KVM_CAP_STEAL_TIME, which I need to disable explicitly at the moment. > > I'm probably missing something since I haven't looked at this, but I'm > wondering what the "VM instance" check is and why it should be necessary. Userspace can check for a KVM_CAP_ on KVM fd (/dev/kvm) or a VM fd (returned via KVM_CREATE_VM). > Shouldn't KVM only expose capabilities which it can provide? I.e. the Correct, given now that we have different "types" of VMs possible on Arm64, (Normal vs Realm vs pVM), the capabilities of each of these could be different and thus we should use the KVM_CAP_ on the VM fd ( referred to VM instance above) and not the generic KVM fd. > "VM instance" check should be done by KVM and, when it fails, the SVE and > steal-time capabilities should return 0. > Correct. Suzuki > Thanks, > drew _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel