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 214E2C54E5D for ; Tue, 12 Mar 2024 15:47:55 +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-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=c80tP0QJHqOVhn+kAXtwU+U/lEnnmkGx4G7Of1qKHrU=; b=mfiaqAC+Caold4 pQqJ1C8FoX/XIJYiqQWbLrOOPv2IxrUJoR+uTVG93n7ou3fAjVrXMXyQHW/XPPX+VPnZZ6tIBx7NE Nl01cjZaLsv3aRM860Z4ZMesbMXTTJY4QBBfvlR4UiCILO3wLZRyskWGR4MGzHwqh+HEnnhXy2W+o LoCAVH/QjCB6GrOB+ts3o1g9QlY1VT12IpNQKJb552J8qVYSm4TP2E9SyORJPfATZjbGE+wGAGlv9 g/faLt0YyaM7Gy0jR0lK7Lha1/zbZoQy6W1RPkJrjvglrIg6nG4jF3ZzoAlmezdx0aymMNzGYoHRr fqUbbvUxxlwG72v6pvdg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rk4Ls-00000006QyG-2g1H; Tue, 12 Mar 2024 15:47:40 +0000 Received: from out-174.mta0.migadu.com ([2001:41d0:1004:224b::ae]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rk4Lj-00000006Qvf-2E9N for linux-arm-kernel@lists.infradead.org; Tue, 12 Mar 2024 15:47:38 +0000 Date: Tue, 12 Mar 2024 08:47:16 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1710258444; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=IBHh3k3RuYYlysG4vpKtI1L13MnMBvP8xcIit+nrqtY=; b=O9yoOEgW8BhLzG2TDA19BQDFTvIiAOMlFuKlMxTj31EWLltBgp9M1mg2KDOdV6i1POGOOz iKT4+h8XoCkn5X865U1ZnNivg1fzpmCZqJKpivy/6l/qV2eUmT/FIvLTdE9E2r3XlfwLP8 kYjxOFuqbx2cjyxgCx275UPlGHSvssI= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Oliver Upton To: David Woodhouse Cc: linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, Paolo Bonzini , Jonathan Corbet , Marc Zyngier , James Morse , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon , Mark Rutland , Lorenzo Pieralisi , "Rafael J. Wysocki" , Len Brown , Pavel Machek , David Woodhouse , Mostafa Saleh , Jean-Philippe Brucker , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev, linux-pm@vger.kernel.org Subject: Re: [RFC PATCH 1/2] KVM: arm64: Add PSCI SYSTEM_OFF2 function for hibernation Message-ID: References: <20240312135958.727765-1-dwmw2@infradead.org> <20240312135958.727765-2-dwmw2@infradead.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20240312135958.727765-2-dwmw2@infradead.org> X-Migadu-Flow: FLOW_OUT X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240312_084736_900367_A0806D41 X-CRM114-Status: GOOD ( 15.90 ) 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-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi, On Tue, Mar 12, 2024 at 01:51:28PM +0000, David Woodhouse wrote: > From: David Woodhouse > > The PSCI v1.3 specification (alpha) adds support for a SYSTEM_OFF2 function > which is analogous to ACPI S4 state. This will allow hosting environments > to determine that a guest is hibernated rather than just powered off, and > ensure that they preserve the virtual environment appropriately to allow > the guest to resume safely (or bump the hardware_signature in the FACS to > trigger a clean reboot instead). > > The beta version will be changed to say that PSCI_FEATURES returns a bit > mask of the supported hibernate types, which is implemented here. Have you considered doing the PSCI implementation in userspace? The SMCCC filter [*] was added for this exact purpose. There are other features being done in userspace (e.g. vCPU hotplug) built on intercepting hypercalls, this seems to be a reasonable candidate too. [*] https://docs.kernel.org/virt/kvm/devices/vm.html#attribute-kvm-arm-vm-smccc-filter-w-o -- Thanks, Oliver _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel