From patchwork Thu Aug 17 14:23:27 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anthony PERARD X-Patchwork-Id: 802701 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=2001:4830:134:3::11; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3xY7kk72MTz9t4P for ; Fri, 18 Aug 2017 00:24:14 +1000 (AEST) Received: from localhost ([::1]:55256 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1diLiW-0001mP-AG for incoming@patchwork.ozlabs.org; Thu, 17 Aug 2017 10:24:12 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34312) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1diLhu-0001kF-V9 for qemu-devel@nongnu.org; Thu, 17 Aug 2017 10:23:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1diLhr-0003Mh-Ny for qemu-devel@nongnu.org; Thu, 17 Aug 2017 10:23:34 -0400 Received: from smtp02.citrix.com ([66.165.176.63]:47564) by eggs.gnu.org with esmtps (TLS1.0:RSA_ARCFOUR_SHA1:16) (Exim 4.71) (envelope-from ) id 1diLhr-0003Lq-Eu for qemu-devel@nongnu.org; Thu, 17 Aug 2017 10:23:31 -0400 X-IronPort-AV: E=Sophos;i="5.41,388,1498521600"; d="scan'208";a="444173730" Date: Thu, 17 Aug 2017 15:23:27 +0100 From: Anthony PERARD To: Igor Mammedov Message-ID: <20170817142327.GE1475@perard.uk.xensource.com> References: <20170815111549.6232-1-anthony.perard@citrix.com> <20170815111549.6232-2-anthony.perard@citrix.com> <20170815140751.2d432a46@nial.brq.redhat.com> <20170815222133-mutt-send-email-mst@kernel.org> <20170816111046.7e0a935d@nial.brq.redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20170816111046.7e0a935d@nial.brq.redhat.com> User-Agent: Mutt/1.8.3 (2017-05-23) X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 66.165.176.63 Subject: Re: [Qemu-devel] [PATCH for-2.10 v2 1/2] hw/acpi: Call acpi_set_pci_info when no ACPI tables needed X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Stefano Stabellini , Eduardo Habkost , "Michael S. Tsirkin" , qemu-devel@nongnu.org, Bruce Rogers , Paolo Bonzini , xen-devel@lists.xenproject.org, Richard Henderson Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" On Wed, Aug 16, 2017 at 11:10:46AM +0200, Igor Mammedov wrote: > On Tue, 15 Aug 2017 22:24:08 +0300 > "Michael S. Tsirkin" wrote: > > > On Tue, Aug 15, 2017 at 02:07:51PM +0200, Igor Mammedov wrote: > > > On Tue, 15 Aug 2017 12:15:48 +0100 > > > Anthony PERARD wrote: > > > > > > > To do PCI passthrough with Xen, the property acpi-pcihp-bsel needs to be > > > > set, but this was done only when ACPI tables are built which is not > > > > needed for a Xen guest. The need for the property starts with commit > > > > "pc: pcihp: avoid adding ACPI_PCIHP_PROP_BSEL twice" > > > > (f0c9d64a68b776374ec4732424a3e27753ce37b6). > > > > > > > > Set pci info before checking for the needs to build ACPI tables. > > > > > > > > Assign bsel=0 property only to the root bus on Xen as there is no > > > > support in the Xen ACPI tables for a different value. > > > > > > looking at hw/acpi/pcihp.c and bsel usage there it looks like > > > bsel property is owned by it and not by ACPI tables, so instead of > > > shuffling it in acpi_setup(), how about moving bsel initialization > > > to hw/acpi/pcihp.c and initialize it there unconditionally? > > > > > > It could be as simple as moving acpi_set_pci_info()/acpi_set_bsel() > > > there and calling it from acpi_pcihp_reset(). > > > > > > Then there won't be need for Xen specific branches, as root bus > > > will have bsel set automatically which is sufficient for Xen and > > > the rest of bsel-s (bridges) will be just unused by Xen, > > > which could later extend its ACPI table implementation to utilize them. > > > > Later is exactly what I'd like to try to avoid. > > Whoever wants acpi hotplug for bridges needs to get > > the bsel info from qemu supplied acpi tables. > > I'd prefer to have only one behavior in QEMU (on hw interface) > side and let Xen to maintain their own ACPI tables dealing > with issues that arise from it since they insist on doing job twice. > > The point is bsel is so embedded in HW part of impl. > that it should be allocated/manged there, otherwise it leads > to hacks where acpi_setup() is called but does partial init > and then bails out to fix code pcihp.c that depend on it being run, > pcihp.c (hw part) shouldn't depend on on ACPI tables generation > (bios part). > > Anyway if you insist on capping Xen, it probably could be done > with comat machinery, something like this: > > (where the 1st hunk should been there since, we've introduced > "acpi-pci-hotplug-with-bridge-support") > > diff --git a/hw/acpi/pcihp.c b/hw/acpi/pcihp.c > index c420a38..a55f022 100644 > --- a/hw/acpi/pcihp.c > +++ b/hw/acpi/pcihp.c > @@ -273,7 +273,7 @@ static void pci_write(void *opaque, hwaddr addr, uint64_t data, > addr, data); > break; > case PCI_SEL_BASE: > - s->hotplug_select = data; > + s->hotplug_select = s->legacy_piix ? 0 : data; > ACPI_PCIHP_DPRINTF("pcisel write %" HWADDR_PRIx " <== %" PRIu64 "\n", > addr, data); > default: > diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c > index 22dbef6..81b8c3e 100644 > --- a/hw/i386/pc_piix.c > +++ b/hw/i386/pc_piix.c > @@ -1117,6 +1117,13 @@ static void xenfv_machine_options(MachineClass *m) > m->max_cpus = HVM_MAX_VCPUS; > m->default_machine_opts = "accel=xen"; > m->hot_add_cpu = pc_hot_add_cpu; > + SET_MACHINE_COMPAT(m, > + {\ > + .driver = "PIIX4_PM",\ > + .property = "acpi-pci-hotplug-with-bridge-support",\ > + .value = "off",\ That property is actually already turned off for Xen, but this is done in piix4_pm_init(). Also, having the property only for xenfv would not be enought because we can use -machine pc,accel=xen. Maybe we could use s->legacy_piix in acpi_pcihp_device_{,un}plug_cb() to find out if the missing bsel property is an issue or not? diff --git a/hw/acpi/pcihp.c b/hw/acpi/pcihp.c index c420a388ea..79b7ed9900 100644 --- a/hw/acpi/pcihp.c +++ b/hw/acpi/pcihp.c @@ -186,6 +186,9 @@ void acpi_pcihp_device_plug_cb(HotplugHandler *hotplug_dev, AcpiPciHpState *s, PCIDevice *pdev = PCI_DEVICE(dev); int slot = PCI_SLOT(pdev->devfn); int bsel = acpi_pcihp_get_bsel(pdev->bus); + + if (bsel < 0 && s->legacy_piix) + bsel = 0; if (bsel < 0) { error_setg(errp, "Unsupported bus. Bus doesn't have property '" ACPI_PCIHP_PROP_BSEL "' set"); @@ -209,6 +212,9 @@ void acpi_pcihp_device_unplug_cb(HotplugHandler *hotplug_dev, AcpiPciHpState *s, PCIDevice *pdev = PCI_DEVICE(dev); int slot = PCI_SLOT(pdev->devfn); int bsel = acpi_pcihp_get_bsel(pdev->bus); + + if (bsel < 0 && s->legacy_piix) + bsel = 0; if (bsel < 0) { error_setg(errp, "Unsupported bus. Bus doesn't have property '" ACPI_PCIHP_PROP_BSEL "' set");