From patchwork Thu Apr 14 00:04:31 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Chamberlain X-Patchwork-Id: 8830021 Return-Path: X-Original-To: patchwork-xen-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 7E3119F3D1 for ; Thu, 14 Apr 2016 00:07:26 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 95D0E20173 for ; Thu, 14 Apr 2016 00:07:25 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9939620274 for ; Thu, 14 Apr 2016 00:07:24 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1aqUmK-0007NC-4Q; Thu, 14 Apr 2016 00:05:00 +0000 Received: from mail6.bemta6.messagelabs.com ([85.158.143.247]) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1aqUmI-0007Mz-H0 for xen-devel@lists.xensource.com; Thu, 14 Apr 2016 00:04:58 +0000 Received: from [85.158.143.35] by server-3.bemta-6.messagelabs.com id D5/63-07120-9AEDE075; Thu, 14 Apr 2016 00:04:57 +0000 X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFmphkeJIrShJLcpLzFFi42I5NlG2Q3flPb5 wg51zJS3uTXnP7sDosb1vF3sAYxRrZl5SfkUCa8ac802MBZulKyZe62dtYDwq1sXIxSEkMJVR Yt7TL6wQzgwmiaWvfjN1MXJwsAnoSty8LdHFyMkhIpAgcffpN2aQGmaBY6wS81bNZQWpERaIk Lh9zwSkhkVAVeLzsgnsIGFeAXuJReeFQcISAnISLT92s4LYnAIOEgt2rgCzhYBK+m8fYISoyZ CY1zOHFcL2klh04xKUrSZx9dwm5gmMfAsYGVYxqhenFpWlFuka6SUVZaZnlOQmZuboGhqY6eW mFhcnpqfmJCYV6yXn525iBIYIAxDsYFz21+kQoyQHk5Ior8kqvnAhvqT8lMqMxOKM+KLSnNTi Q4wyHBxKEryH7wLlBItS01Mr0jJzgMEKk5bg4FES4d0OkuYtLkjMLc5Mh0idYtTl2LLgxlomI Za8/LxUKXHeGSBFAiBFGaV5cCNgkXOJUVZKmJcR6CghnoLUotzMElT5V4ziHIxKwrxnQKbwZO aVwG16BXQEE9ARZe94QY4oSURISTUwNquf+vZQbkFzwcmNc55L9j1+OM1MU43D4ctd36BjhVc OfPG/zfV5CqeqUdv6d1nrtNvcg+2/ybRzrxfY+6LasD2JzfBFmar7O95crzovK6vqa3x2K1fG 8Ah7X5/5mScogH3Wr7k3Am/o9xfvSww/3OLp4ZU7Z82WzBN8J15/Ect7qeu7JcVLiaU4I9FQi 7moOBEAC4Zm85cCAAA= X-Env-Sender: mcgrof@kernel.org X-Msg-Ref: server-4.tower-21.messagelabs.com!1460592296!6895227!1 X-Originating-IP: [198.145.29.136] X-SpamReason: No, hits=0.0 required=7.0 tests= X-StarScan-Received: X-StarScan-Version: 8.28; banners=-,-,- X-VirusChecked: Checked Received: (qmail 54787 invoked from network); 14 Apr 2016 00:04:57 -0000 Received: from mail.kernel.org (HELO mail.kernel.org) (198.145.29.136) by server-4.tower-21.messagelabs.com with DHE-RSA-AES256-GCM-SHA384 encrypted SMTP; 14 Apr 2016 00:04:57 -0000 Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 7DB3C20173; Thu, 14 Apr 2016 00:04:54 +0000 (UTC) Received: from garbanzo.do-not-panic.com (c-73-15-241-2.hsd1.ca.comcast.net [73.15.241.2]) (using TLSv1.2 with cipher AES128-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4F142201BB; Thu, 14 Apr 2016 00:04:52 +0000 (UTC) From: "Luis R. Rodriguez" To: bp@alien8.de, hpa@zytor.com, tglx@linutronix.de, mingo@redhat.com, rusty@rustcorp.com.au Date: Wed, 13 Apr 2016 17:04:31 -0700 Message-Id: <1460592286-300-2-git-send-email-mcgrof@kernel.org> X-Mailer: git-send-email 2.7.0 In-Reply-To: <1460592286-300-1-git-send-email-mcgrof@kernel.org> References: <1460592286-300-1-git-send-email-mcgrof@kernel.org> X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Cc: kozerkov@parallels.com, matt@codeblueprint.co.uk, bigeasy@linutronix.de, lv.zheng@intel.com, ffainelli@freebox.fr, mbizon@freebox.fr, xen-devel@lists.xensource.com, x86@kernel.org, robert.moore@intel.com, linux-acpi@vger.kernel.org, glin@suse.com, lenb@kernel.org, julien.grall@linaro.org, josh@joshtriplett.org, george.dunlap@citrix.com, jlee@suse.com, lguest@lists.ozlabs.org, boris.ostrovsky@oracle.com, andriy.shevchenko@linux.intel.com, jgross@suse.com, toshi.kani@hp.com, andrew.cooper3@citrix.com, rjw@rjwysocki.net, linux-kernel@vger.kernel.org, luto@amacapital.net, "Luis R. Rodriguez" , david.vrabel@citrix.com, tiwai@suse.de Subject: [Xen-devel] [PATCH v6 01/16] x86/boot: enumerate documentation for the x86 hardware_subarch X-BeenThere: xen-devel@lists.xen.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" X-Virus-Scanned: ClamAV using ClamSMTP Although hardware_subarch has been in place since the x86 boot protocol 2.07 it hasn't been used much. Enumerate current possible values to avoid misuses and help with semantics later at boot time should this be used further. These enums should only ever be used by architecture x86 code, and all that code should be well contained and compartamentalized, clarify that as well. v4: updates documentation further -- be a bit more pedantic about annotating care and use of these guys. v5: Use s/SOC/SoC and also anntoate that both domU and dom0 are both currently supported through the PV boot path. v6: add big fat warning about how this is for legacy platforms only, as per Ingo's request Signed-off-by: Luis R. Rodriguez --- arch/x86/include/uapi/asm/bootparam.h | 41 ++++++++++++++++++++++++++++++++++- 1 file changed, 40 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h index 329254373479..c18ce67495fa 100644 --- a/arch/x86/include/uapi/asm/bootparam.h +++ b/arch/x86/include/uapi/asm/bootparam.h @@ -157,7 +157,46 @@ struct boot_params { __u8 _pad9[276]; /* 0xeec */ } __attribute__((packed)); -enum { +/** + * enum x86_hardware_subarch - x86 hardware subarchitecture + * + * The x86 hardware_subarch and hardware_subarch_data were added as of the x86 + * boot protocol 2.07 to help distinguish and support custom x86 boot + * sequences. This enum represents accepted values for the x86 + * hardware_subarch. Custom x86 boot sequences (not X86_SUBARCH_PC) do not + * have or simply *cannot* make use of natural stubs like BIOS or EFI, the + * hardware_subarch can be used on the Linux entry path to revector to a + * subarchitecture stub when needed. This subarchitecture stub can be used to + * set up Linux boot parameters or for special care to account for nonstandard + * handling of page tables. + * + * These enums should only ever be used by x86 code, and the code that uses + * it should be well contained and compartamentalized. + * + * KVM and Xen HVM do not have a subarch as these are expected to follow + * standard x86 boot entries. If there is a genuine need for "hypervisor" type + * that should be considered separately in the future. Future guest types + * should seriously consider working with standard x86 boot stubs such as + * the BIOS or EFI boot stubs. + * + * WARNING: this enum is only used for legacy hacks, for platform features that + * are not easily enumerated or discoverable. You should not ever use + * this for new features. + * + * @X86_SUBARCH_PC: Should be used if the hardware is enumerable using standard + * PC mechanisms (PCI, ACPI) and doesn't need a special boot flow. + * @X86_SUBARCH_LGUEST: Used for x86 hypervisor demo, lguest + * @X86_SUBARCH_XEN: Used for Xen guest types which follow the PV boot path, + * which start at asm startup_xen() entry point and later jump to the C + * xen_start_kernel() entry point. Both domU and dom0 type of guests are + * currently supportd through this PV boot path. + * @X86_SUBARCH_INTEL_MID: Used for Intel MID (Mobile Internet Device) platform + * systems which do not have the PCI legacy interfaces. + * @X86_SUBARCH_CE4100: Used for Intel CE media processor (CE4100) SoC for + * for settop boxes and media devices, the use of a subarch for CE4100 + * is more of a hack... + */ +enum x86_hardware_subarch { X86_SUBARCH_PC = 0, X86_SUBARCH_LGUEST, X86_SUBARCH_XEN,