From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49557) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bziTP-00079n-SO for qemu-devel@nongnu.org; Thu, 27 Oct 2016 07:03:55 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bziTK-00020D-Sk for qemu-devel@nongnu.org; Thu, 27 Oct 2016 07:03:51 -0400 Received: from smtp.citrix.com ([66.165.176.89]:19006) by eggs.gnu.org with esmtps (TLS1.0:RSA_ARCFOUR_SHA1:16) (Exim 4.71) (envelope-from ) id 1bziTK-0001yx-Lu for qemu-devel@nongnu.org; Thu, 27 Oct 2016 07:03:46 -0400 Date: Thu, 27 Oct 2016 12:03:42 +0100 From: Wei Liu Message-ID: <20161027110342.GY30231@citrix.com> References: <1477416484-29054-1-git-send-email-wei.liu2@citrix.com> <20161026170952.18c02dbb@nial.brq.redhat.com> <20161026152234.GQ30231@citrix.com> <20161027125402.63484b99@nial.brq.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20161027125402.63484b99@nial.brq.redhat.com> Subject: Re: [Qemu-devel] [PATCH RFC] acpi: don't build acpi tables for xen hvm guests List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Igor Mammedov Cc: Wei Liu , Anthony PERARD , Xen-devel , Stefano Stabellini , qemu-devel@nongnu.org, Sander Eikelenboom Cc Sander On Thu, Oct 27, 2016 at 12:54:02PM +0200, Igor Mammedov wrote: > On Wed, 26 Oct 2016 16:22:34 +0100 > Wei Liu wrote: > > > On Wed, Oct 26, 2016 at 05:09:52PM +0200, Igor Mammedov wrote: > > > On Tue, 25 Oct 2016 18:28:04 +0100 > > > Wei Liu wrote: > > > > > > > Xen's toolstack is in charge of building ACPI tables. Skip acpi table > > > > building if running on Xen. > > > > > > > > This issue is discovered due to direct kernel boot on Xen doesn't boot > > > > anymore, because the new ACPI tables cause the guest to exceed its > > > > memory allocation limit. > > > > > > > > Reported-by: Sander Eikelenboom > > > > Signed-off-by: Wei Liu > > > Question is: > > > Why does xen guest get ACPI tables from QEMU instead of using > > > Xen provided ones. > > > Maybe it's firmware issue i.e. firmware side shouldn't load > > > ACPI tables from QEMU provided fwcfg file and load Xen provided instead. > > > > > > > It hasn't come to the point that the guest is booted. QEMU exits when > > trying to populate some pages for the guest, at which point the guest > > has not yet been started. In a sense, Xen guest doesn't get ACPI from > > QEMU because it never gets to that point. > > > > Direct kernel boot causes fw_cfg to be filled in. pcms->has_acpi_build > > defaults to true and acpi_enabled is also true. These make all checks in > > acpi_setup pass. QEMU proceeds to build and load ACPI tables (which are > > never going to be used by Xen guests), causing the guest to exceeds its > > limit. > > > > Wei. > Would something like this fix issue for you? > > diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c > index a54a468..61b6026 100644 > --- a/hw/i386/pc_piix.c > +++ b/hw/i386/pc_piix.c > @@ -1094,10 +1094,13 @@ DEFINE_PC_MACHINE(isapc, "isapc", pc_init_isa, > #ifdef CONFIG_XEN > static void xenfv_machine_options(MachineClass *m) > { > + PCMachineClass *pcmc = PC_MACHINE_CLASS(m); > + > m->desc = "Xen Fully-virtualized PC"; > m->max_cpus = HVM_MAX_VCPUS; > m->default_machine_opts = "accel=xen"; > m->hot_add_cpu = pc_hot_add_cpu; > + pcmc->has_acpi_build = false; > } > > DEFINE_PC_MACHINE(xenfv, "xenfv", pc_xen_hvm_init, > Yes, it does. (I have a similar patch in my queue already) Wei.