From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58144) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XoWPa-00030m-1Z for qemu-devel@nongnu.org; Wed, 12 Nov 2014 06:48:43 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XoWPZ-0003zF-9c for qemu-devel@nongnu.org; Wed, 12 Nov 2014 06:48:33 -0500 Received: from mail-wi0-x22b.google.com ([2a00:1450:400c:c05::22b]:50400) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XoWPZ-0003yu-1k for qemu-devel@nongnu.org; Wed, 12 Nov 2014 06:48:33 -0500 Received: by mail-wi0-f171.google.com with SMTP id r20so4609631wiv.4 for ; Wed, 12 Nov 2014 03:48:32 -0800 (PST) Sender: Paolo Bonzini Message-ID: <5463490B.9080101@redhat.com> Date: Wed, 12 Nov 2014 12:48:27 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <1414691045-4793-1-git-send-email-a.spyridakis@virtualopensystems.com> <546323A7.6040805@huawei.com> <20141112105640.GB28015@leverpostej> <1857764.BysEu3dgOQ@wuerfel> <20141112113401.GH19598@cbox> In-Reply-To: <20141112113401.GH19598@cbox> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [Linaro-acpi] [RFC PATCH 0/7] hw/arm/virt: Dynamic ACPI v5.1 table generation List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Christoffer Dall , Arnd Bergmann Cc: Mark Rutland , Peter Maydell , linaro-acpi@lists.linaro.org, Paul Mundt , Claudio Fontana , QEMU Developers , Jani Kokkonen , "tech@virtualopensystems.com" On 12/11/2014 12:34, Christoffer Dall wrote: > AFAIU ACPI already has a method for doing this It's not defined in the spec. QEMU defines a bunch of registers to do that, and provides AML that works with those registers. While these registers can be separated from the ACPI code in QEMU... > and I speculate that there is some IRQ > assigned to an ACPI event that causes some AML code to be interpreted by > your OS. ... QEMU does exactly this, it uses the "general purpose event" (GPE) mechanism to trigger the parsing of the AML. When you hot-plug/unplug a CPU or memory, an SCI (system control interrupt - the ACPI IRQ) is triggered in the guest and that's not entirely disconnected from ACPI. Perhaps you could treat it as a shared level-triggered interrupt in DT? I don't know. > Wouldn't it be a matter of QEMU putting the right AML table > fragments in place to wire this up then? Yes. Paolo