From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752762AbbIKNQM (ORCPT ); Fri, 11 Sep 2015 09:16:12 -0400 Received: from smtp.citrix.com ([66.165.176.89]:59900 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751795AbbIKNQK (ORCPT ); Fri, 11 Sep 2015 09:16:10 -0400 X-IronPort-AV: E=Sophos;i="5.17,511,1437436800"; d="scan'208";a="299435767" Date: Fri, 11 Sep 2015 14:14:09 +0100 From: Stefano Stabellini X-X-Sender: sstabellini@kaball.uk.xensource.com To: Daniel Kiper CC: Mark Rutland , Stefano Stabellini , Shannon Zhao , "linux-arm-kernel@lists.infradead.org" , "devicetree@vger.kernel.org" , "linux-efi@vger.kernel.org" , "Ian.Campbell@citrix.com" , "linux-doc@vger.kernel.org" , "ard.biesheuvel@linaro.org" , "linux-kernel@vger.kernel.org" , "leif.lindholm@linaro.org" , "xen-devel@lists.xen.org" , "julien.grall@citrix.com" , "freebsd-arm@freebsd.org" , "matt.fleming@intel.com" , "christoffer.dall@linaro.org" , "jbeulich@suse.com" , "peter.huangpeng@huawei.com" , "shannon.zhao@linaro.org" , Konrad Rzeszutek Wilk Subject: Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub parameters In-Reply-To: <20150911124643.GB4530@olila.local.net-space.pl> Message-ID: References: <1441874516-11364-1-git-send-email-zhaoshenglong@huawei.com> <20150910095208.GA29293@leverpostej> <20150910112418.GC29293@leverpostej> <20150910121514.GE29293@leverpostej> <20150910144938.GI29293@leverpostej> <20150910162302.GN29293@leverpostej> <20150911124643.GB4530@olila.local.net-space.pl> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" X-DLP: MIA2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 11 Sep 2015, Daniel Kiper wrote: > On Thu, Sep 10, 2015 at 05:23:02PM +0100, Mark Rutland wrote: > > > > C) When you could go: > > > > > > > > DT -> Discover Xen -> Xen-specific stuff -> Xen-specific EFI/ACPI discovery > > > > > > I take you mean discovering Xen with the usual Xen hypervisor node on > > > device tree. I think that C) is a good option actually. I like it. Not > > > sure why we didn't think about this earlier. Is there anything EFI or > > > ACPI which is needed before Xen support is discovered by > > > arch/arm64/kernel/setup.c:setup_arch -> xen_early_init()? > > > > Currently lots (including the memory map). With the stuff to support > > SPCR, the ACPI discovery would be moved before xen_early_init(). > > > > > If not, we could just go for this. A lot of complexity would go away. > > > > I suspect this would still be fairly complex, but would at least prevent > > the Xen-specific EFI handling from adversely affecting the native case. > > > > > > D) If you want to be generic: > > > > EFI -> EFI application -> EFI tables -> ACPI tables -> Xen-specific stuff > > > > \------------------------------------------/ > > > > (virtualize these, provide shims to Dom0, but handle > > > > everything in Xen itself) > > > > > > I think that this is good in theory but could turn out to be a lot of > > > work in practice. We could probably virtualize the RuntimeServices but > > > the BootServices are troublesome. > > > > What's troublesome with the boot services? > > > > What can't be simulated? > > How do you want to access bare metal EFI boot services from dom0 if they > were shutdown long time ago before loading dom0 image? What do you need > from EFI boot services in dom0? That's right. Trying to emulate BootServices after the real ExitBootServices has already been called seems like a very bad plan. I think that whatever interface we come up with, would need to be past ExitBootServices. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefano Stabellini Subject: Re: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub parameters Date: Fri, 11 Sep 2015 14:14:09 +0100 Message-ID: References: <1441874516-11364-1-git-send-email-zhaoshenglong@huawei.com> <20150910095208.GA29293@leverpostej> <20150910112418.GC29293@leverpostej> <20150910121514.GE29293@leverpostej> <20150910144938.GI29293@leverpostej> <20150910162302.GN29293@leverpostej> <20150911124643.GB4530@olila.local.net-space.pl> Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Return-path: In-Reply-To: <20150911124643.GB4530-fJNZiO034lp9pOct4yEdx/3oZC3j2Omk@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Daniel Kiper Cc: Mark Rutland , Stefano Stabellini , Shannon Zhao , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "Ian.Campbell-Sxgqhf6Nn4DQT0dZR+AlfA@public.gmane.org" , "linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "leif.lindholm-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org" , "xen-devel-GuqFBffKawuEi8DpZVb4nw@public.gmane.org" , "julien.grall-Sxgqhf6Nn4DQT0dZR+AlfA@public.gmane.org" , "freebsd-arm-h+KGxgPPiopAfugRpC6u6w@public.gmane.org" , "matt.fleming-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org" , "christoffer.dall-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org" List-Id: linux-efi@vger.kernel.org On Fri, 11 Sep 2015, Daniel Kiper wrote: > On Thu, Sep 10, 2015 at 05:23:02PM +0100, Mark Rutland wrote: > > > > C) When you could go: > > > > > > > > DT -> Discover Xen -> Xen-specific stuff -> Xen-specific EFI/ACPI discovery > > > > > > I take you mean discovering Xen with the usual Xen hypervisor node on > > > device tree. I think that C) is a good option actually. I like it. Not > > > sure why we didn't think about this earlier. Is there anything EFI or > > > ACPI which is needed before Xen support is discovered by > > > arch/arm64/kernel/setup.c:setup_arch -> xen_early_init()? > > > > Currently lots (including the memory map). With the stuff to support > > SPCR, the ACPI discovery would be moved before xen_early_init(). > > > > > If not, we could just go for this. A lot of complexity would go away. > > > > I suspect this would still be fairly complex, but would at least prevent > > the Xen-specific EFI handling from adversely affecting the native case. > > > > > > D) If you want to be generic: > > > > EFI -> EFI application -> EFI tables -> ACPI tables -> Xen-specific stuff > > > > \------------------------------------------/ > > > > (virtualize these, provide shims to Dom0, but handle > > > > everything in Xen itself) > > > > > > I think that this is good in theory but could turn out to be a lot of > > > work in practice. We could probably virtualize the RuntimeServices but > > > the BootServices are troublesome. > > > > What's troublesome with the boot services? > > > > What can't be simulated? > > How do you want to access bare metal EFI boot services from dom0 if they > were shutdown long time ago before loading dom0 image? What do you need > from EFI boot services in dom0? That's right. Trying to emulate BootServices after the real ExitBootServices has already been called seems like a very bad plan. I think that whatever interface we come up with, would need to be past ExitBootServices. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 From: stefano.stabellini@eu.citrix.com (Stefano Stabellini) Date: Fri, 11 Sep 2015 14:14:09 +0100 Subject: [PATCH] efi/libstub/fdt: Standardize the names of EFI stub parameters In-Reply-To: <20150911124643.GB4530@olila.local.net-space.pl> References: <1441874516-11364-1-git-send-email-zhaoshenglong@huawei.com> <20150910095208.GA29293@leverpostej> <20150910112418.GC29293@leverpostej> <20150910121514.GE29293@leverpostej> <20150910144938.GI29293@leverpostej> <20150910162302.GN29293@leverpostej> <20150911124643.GB4530@olila.local.net-space.pl> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, 11 Sep 2015, Daniel Kiper wrote: > On Thu, Sep 10, 2015 at 05:23:02PM +0100, Mark Rutland wrote: > > > > C) When you could go: > > > > > > > > DT -> Discover Xen -> Xen-specific stuff -> Xen-specific EFI/ACPI discovery > > > > > > I take you mean discovering Xen with the usual Xen hypervisor node on > > > device tree. I think that C) is a good option actually. I like it. Not > > > sure why we didn't think about this earlier. Is there anything EFI or > > > ACPI which is needed before Xen support is discovered by > > > arch/arm64/kernel/setup.c:setup_arch -> xen_early_init()? > > > > Currently lots (including the memory map). With the stuff to support > > SPCR, the ACPI discovery would be moved before xen_early_init(). > > > > > If not, we could just go for this. A lot of complexity would go away. > > > > I suspect this would still be fairly complex, but would at least prevent > > the Xen-specific EFI handling from adversely affecting the native case. > > > > > > D) If you want to be generic: > > > > EFI -> EFI application -> EFI tables -> ACPI tables -> Xen-specific stuff > > > > \------------------------------------------/ > > > > (virtualize these, provide shims to Dom0, but handle > > > > everything in Xen itself) > > > > > > I think that this is good in theory but could turn out to be a lot of > > > work in practice. We could probably virtualize the RuntimeServices but > > > the BootServices are troublesome. > > > > What's troublesome with the boot services? > > > > What can't be simulated? > > How do you want to access bare metal EFI boot services from dom0 if they > were shutdown long time ago before loading dom0 image? What do you need > from EFI boot services in dom0? That's right. Trying to emulate BootServices after the real ExitBootServices has already been called seems like a very bad plan. I think that whatever interface we come up with, would need to be past ExitBootServices.