From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755613Ab2HAPqB (ORCPT ); Wed, 1 Aug 2012 11:46:01 -0400 Received: from smtp.eu.citrix.com ([62.200.22.115]:65199 "EHLO SMTP.EU.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753483Ab2HAPp7 (ORCPT ); Wed, 1 Aug 2012 11:45:59 -0400 X-IronPort-AV: E=Sophos;i="4.77,694,1336348800"; d="scan'208";a="13807298" Date: Wed, 1 Aug 2012 16:45:40 +0100 From: Stefano Stabellini X-X-Sender: sstabellini@kaball.uk.xensource.com To: Konrad Rzeszutek Wilk CC: Stefano Stabellini , "linux-kernel@vger.kernel.org" , "xen-devel@lists.xensource.com" , Ian Campbell , "Tim (Xen.org)" , "linux-arm-kernel@lists.infradead.org" , "linaro-dev@lists.linaro.org" , "catalin.marinas@arm.com" , "arnd@arndb.de" Subject: Re: [PATCH 07/24] xen/arm: Xen detection and shared_info page mapping In-Reply-To: <20120801141959.GE7227@phenom.dumpdata.com> Message-ID: References: <1343316846-25860-7-git-send-email-stefano.stabellini@eu.citrix.com> <20120801141959.GE7227@phenom.dumpdata.com> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 1 Aug 2012, Konrad Rzeszutek Wilk wrote: > On Thu, Jul 26, 2012 at 04:33:49PM +0100, Stefano Stabellini wrote: > > Check for a "/xen" node in the device tree, if it is present set > > xen_domain_type to XEN_HVM_DOMAIN and continue initialization. > > > > Map the real shared info page using XENMEM_add_to_physmap with > > XENMAPSPACE_shared_info. > > > > Signed-off-by: Stefano Stabellini > > --- > > arch/arm/xen/enlighten.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++ > > 1 files changed, 56 insertions(+), 0 deletions(-) > > > > diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c > > index d27c2a6..8c923af 100644 > > --- a/arch/arm/xen/enlighten.c > > +++ b/arch/arm/xen/enlighten.c > > @@ -5,6 +5,9 @@ > > #include > > #include > > #include > > +#include > > +#include > > +#include > > > > struct start_info _xen_start_info; > > struct start_info *xen_start_info = &_xen_start_info; > > @@ -33,3 +36,56 @@ int xen_remap_domain_mfn_range(struct vm_area_struct *vma, > > return -ENOSYS; > > } > > EXPORT_SYMBOL_GPL(xen_remap_domain_mfn_range); > > + > > +/* > > + * == Xen Device Tree format == > > + * - /xen node; > > + * - compatible "arm,xen"; > > + * - one interrupt for Xen event notifications; > > + * - one memory region to map the grant_table. > > + */ > > +static int __init xen_guest_init(void) > > +{ > > + int cpu; > > + struct xen_add_to_physmap xatp; > > + static struct shared_info *shared_info_page = 0; > > + struct device_node *node; > > + > > + node = of_find_compatible_node(NULL, NULL, "arm,xen"); > > + if (!node) { > > + pr_info("No Xen support\n"); > > I don't think the pr_info is appropiate here? Yes, you are right. In fact I had already turned it into a pr_debug. > > + return 0; > > Should this be -ENODEV? Considering that xen_guest_init is called by a core_initcall, I didn't want to return an error just because Xen is not present on the platform. > > + } > > + xen_domain_type = XEN_HVM_DOMAIN; > > + > > + if (!shared_info_page) > > + shared_info_page = (struct shared_info *) > > + get_zeroed_page(GFP_KERNEL); > > + if (!shared_info_page) { > > + pr_err("not enough memory"); > > \n OK > > + return -ENOMEM; > > + } > > + xatp.domid = DOMID_SELF; > > + xatp.idx = 0; > > + xatp.space = XENMAPSPACE_shared_info; > > + xatp.gpfn = __pa(shared_info_page) >> PAGE_SHIFT; > > + if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp)) > > + BUG(); > > + > > + HYPERVISOR_shared_info = (struct shared_info *)shared_info_page; > > + > > + /* xen_vcpu is a pointer to the vcpu_info struct in the shared_info > > + * page, we use it in the event channel upcall and in some pvclock > > + * related functions. We don't need the vcpu_info placement > > + * optimizations because we don't use any pv_mmu or pv_irq op on > > + * HVM. > > + * When xen_hvm_init_shared_info is run at boot time only vcpu 0 is > > + * online but xen_hvm_init_shared_info is run at resume time too and > > + * in that case multiple vcpus might be online. */ > > + for_each_online_cpu(cpu) { > > + per_cpu(xen_vcpu, cpu) = > > + &HYPERVISOR_shared_info->vcpu_info[cpu]; > > + } > > + return 0; > > This above looks stringly similar to the x86 one. Could it be > abstracted away to share the same code? Or is that something that > ought to be done later on when there is more meat on the bone? Actually I had to remove these three lines because on ARM we are going to have just one vcpu_info struct in the shared_info page and then rely on VCPUOP_register_vcpu_info.