From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58043) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gIZbA-0002DG-Om for qemu-devel@nongnu.org; Fri, 02 Nov 2018 09:34:54 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gIZb7-00033O-4Y for qemu-devel@nongnu.org; Fri, 02 Nov 2018 09:34:52 -0400 References: <20181024101930.20674-1-david@redhat.com> <20181024101930.20674-3-david@redhat.com> <20181101151034.4eb1618c@redhat.com> <85802555-0f27-847d-22a9-e87ce2e5df55@redhat.com> <20181102140032.43f6c93c@redhat.com> From: David Hildenbrand Message-ID: <84cb2e23-7004-fec5-e4de-8f4c2c9725b3@redhat.com> Date: Fri, 2 Nov 2018 14:34:40 +0100 MIME-Version: 1.0 In-Reply-To: <20181102140032.43f6c93c@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v1 2/7] pcihp: overwrite hotplug handler recursively from the start List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Igor Mammedov Cc: qemu-devel@nongnu.org, "Michael S . Tsirkin" , Marcel Apfelbaum , qemu-ppc@nongnu.org, Libvirt On 02.11.18 14:00, Igor Mammedov wrote: > On Fri, 2 Nov 2018 12:43:10 +0100 > David Hildenbrand wrote: > >> On 01.11.18 15:10, Igor Mammedov wrote: >>> On Wed, 24 Oct 2018 12:19:25 +0200 >>> David Hildenbrand wrote: >>> >>>> For now, the hotplug handler is not called for devices that are >>>> being cold plugged. The hotplug handler is setup when the machine >>>> initialization is fully done. Only bridges that were cold plugged are >>>> considered. >>>> >>>> Set the hotplug handler for the root piix bus directly when realizing. >>>> Overwrite the hotplug handler of bridges when hotplugging/coldplugging >>>> them. >>>> >>>> This will now make sure that the ACPI PCI hotplug handler is also called >>>> for cold-plugged devices (also on bridges) and for bridges that were >>>> hotplugged. >>>> >>>> When trying to hotplug a device to a hotplugged bridge, we now correctly >>>> get the error message >>>> "Unsupported bus. Bus doesn't have property 'acpi-pcihp-bsel' set" >>>> Insted of going via the standard PCI hotplug handler. >>> Erroring out is probably not ok, since it can break existing setups >>> where SHPC hotplugging to hotplugged bridge was working just fine before. >> >> The question is if it actually was supposed (and eventually did) work. > I think it works now, it's QEMU 'ACPI hotplug hack' (which exists for > the sake of Windows) limitation. We weren't able to dynamically add > ACPI description for hotplugged bridge, so it was using native hotplug. > Now theoretically we can load tables dynamically but that, would add > maintenance nightmare (versioned tables) and would be harder to debug. > I'd rather not go that direction and keep current limited version, > suggesting users to use native hotplug if guest is capable. Alright I'll keep current behavior (checking if the bridge is hotplugged or coldplugged). Thanks! -- Thanks, David / dhildenb