From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34703) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a3laq-0005zM-AD for qemu-devel@nongnu.org; Tue, 01 Dec 2015 09:07:48 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1a3lal-0005sU-5Y for qemu-devel@nongnu.org; Tue, 01 Dec 2015 09:07:44 -0500 Received: from mx1.redhat.com ([209.132.183.28]:53141) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a3lak-0005sM-Vh for qemu-devel@nongnu.org; Tue, 01 Dec 2015 09:07:39 -0500 References: <1448553628-5446-1-git-send-email-marcel@redhat.com> <1448553628-5446-4-git-send-email-marcel@redhat.com> <20151127172852.GZ23717@thinpad.lan.raisama.net> <565ABB4B.9080703@redhat.com> <20151130150733.GG23717@thinpad.lan.raisama.net> From: Marcel Apfelbaum Message-ID: <565DA9A5.8010408@redhat.com> Date: Tue, 1 Dec 2015 16:07:33 +0200 MIME-Version: 1.0 In-Reply-To: <20151130150733.GG23717@thinpad.lan.raisama.net> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH V3 3/3] hw/i386: extend pxb query for all PC machines List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eduardo Habkost Cc: mst@redhat.com, qemu-devel@nongnu.org, armbru@redhat.com, kraxel@redhat.com, laine@redhat.com, pbonzini@redhat.com, imammedo@redhat.com, lersek@redhat.com, rth@twiddle.net On 11/30/2015 05:07 PM, Eduardo Habkost wrote: > On Sun, Nov 29, 2015 at 10:46:03AM +0200, Marcel Apfelbaum wrote: >> On 11/27/2015 07:28 PM, Eduardo Habkost wrote: >>> On Thu, Nov 26, 2015 at 06:00:28PM +0200, Marcel Apfelbaum wrote: >>>> Add bus property to PC machines and use it when looking >>>> for primary PCI root bus (bus 0). >>>> >>>> Signed-off-by: Marcel Apfelbaum >>> >>> I can't pretend I have reviewed the q35 part, but the changes are >>> an improvement to the existing code that depended on >>> find_i440fx(). >>> >>> Acked-by: Eduardo Habkost >> >> Thanks! >> >>> >>> BTW, what's missing to allow us to change acpi_set_pci_info() to >>> use PCMachine::bus instead of find_i440fx(), too? How much of the >>> PCI hotplug stuff is different in q35? >> >> It is pretty different. >> i440fx has acpi based hotplug while q35 has PCIe native hotplug. Since is >> "native", no acpi info is necessary. >> >> Having said that, if we have an PCIe-PCI bridge, the pci devices behind it >> cannot be hotplugged/unplugged right now. >> >> Once we decide to add hotplug support for this scenario, maybe we can get rid of >> find_i440fx(). > > Thanks for the explanation. I wonder if there's a better way to > check if ACPI-based hotplug is needed by looking at > PCMachineState or PCIBus, so we don't couple the ACPI code to > piix.c. > I suppose we can do something about it, like adding a property to PCMachineState, lets say bool acpi_hotplug and set it false for Q35. Then we have: pcm = PC_MACHINE(current_machine); if(pcm->acpi_hotplug) { bus = pcm->bus; ... } Sounds acceptable? If yes, I'll send a patch on top since is not directly related. Thanks, Marcel