From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51388) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a3mLd-0003rQ-EV for qemu-devel@nongnu.org; Tue, 01 Dec 2015 09:56:09 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1a3mLa-0004ZX-OB for qemu-devel@nongnu.org; Tue, 01 Dec 2015 09:56:05 -0500 Received: from mx1.redhat.com ([209.132.183.28]:42788) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a3mLa-0004ZS-Gv for qemu-devel@nongnu.org; Tue, 01 Dec 2015 09:56:02 -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> <565DA9A5.8010408@redhat.com> <20151201144816.GI23717@thinpad.lan.raisama.net> From: Marcel Apfelbaum Message-ID: <565DB4FD.7050909@redhat.com> Date: Tue, 1 Dec 2015 16:55:57 +0200 MIME-Version: 1.0 In-Reply-To: <20151201144816.GI23717@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 12/01/2015 04:48 PM, Eduardo Habkost wrote: > On Tue, Dec 01, 2015 at 04:07:33PM +0200, Marcel Apfelbaum wrote: >> 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.S > > There's no existing field or method in PCIBus that can be already > used for that? Hmm, you can derive the info you need from pci_bus_is_express. If express-> no acpi_hotplug. This is not 100% true, but since we don't support acpi hotplug on PCIe machines, it should be OK for now. If not, that sounds good to me. But I would move > the field to PCMachineClass instead of PCMachineState. Sure. > > Would you like me to do it? I am planning to submit other changes > to remove q35/piix dependencies from acpi-build.c. > If you have the time, go for it :) Is a "one liner", if applied on top of this series. Thanks, Marcel