Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751493AbWEII4X (ORCPT ); Tue, 9 May 2006 04:56:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751500AbWEIItO (ORCPT ); Tue, 9 May 2006 04:49:14 -0400 Received: from 216-99-217-87.dsl.aracnet.com ([216.99.217.87]:2688 "EHLO sous-sol.org") by vger.kernel.org with ESMTP id S1751513AbWEIIsx (ORCPT ); Tue, 9 May 2006 04:48:53 -0400 Message-Id: <20060509085158.933866000@sous-sol.org> References: <20060509084945.373541000@sous-sol.org> Date: Tue, 09 May 2006 00:00:28 -0700 From: Chris Wright To: linux-kernel@vger.kernel.org Cc: virtualization@lists.osdl.org, xen-devel@lists.xensource.com, Ian Pratt , Christian Limpach Subject: [RFC PATCH 28/35] add support for Xen feature queries Content-Disposition: inline; filename=xen-features Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3454 Lines: 114 Add support for parsing and interpreting hypervisor feature flags. These allow the kernel to determine what features are provided by the underlying hypervisor. For example, whether page tables need to be write protected explicitly by the kernel, and whether the kernel (appears to) run in ring 0 rather than ring 1. This information allows the kernel to improve performance by avoiding unnecessary actions. Signed-off-by: Ian Pratt Signed-off-by: Christian Limpach Signed-off-by: Chris Wright --- drivers/Makefile | 1 drivers/xen/Makefile | 3 ++ drivers/xen/core/Makefile | 3 ++ drivers/xen/core/features.c | 29 ++++++++++++++++++++++++++++ include/asm-i386/mach-xen/setup_arch_post.h | 2 + include/xen/features.h | 20 +++++++++++++++++++ 6 files changed, 58 insertions(+) --- linus-2.6.orig/include/asm-i386/mach-xen/setup_arch_post.h +++ linus-2.6/include/asm-i386/mach-xen/setup_arch_post.h @@ -27,6 +27,8 @@ static void __init machine_specific_arch { struct physdev_op op; + setup_xen_features(); + HYPERVISOR_shared_info = (struct shared_info *)__va(xen_start_info->shared_info); memset(empty_zero_page, 0, sizeof(empty_zero_page)); --- linus-2.6.orig/drivers/Makefile +++ linus-2.6/drivers/Makefile @@ -31,6 +31,7 @@ obj-y += base/ block/ misc/ mfd/ net/ obj-$(CONFIG_NUBUS) += nubus/ obj-$(CONFIG_ATM) += atm/ obj-$(CONFIG_PPC_PMAC) += macintosh/ +obj-$(CONFIG_XEN) += xen/ obj-$(CONFIG_IDE) += ide/ obj-$(CONFIG_FC4) += fc4/ obj-$(CONFIG_SCSI) += scsi/ --- /dev/null +++ linus-2.6/include/xen/features.h @@ -0,0 +1,20 @@ +/****************************************************************************** + * features.h + * + * Query the features reported by Xen. + * + * Copyright (c) 2006, Ian Campbell + */ + +#ifndef __ASM_XEN_FEATURES_H__ +#define __ASM_XEN_FEATURES_H__ + +#include + +extern void setup_xen_features(void); + +extern u8 xen_features[XENFEAT_NR_SUBMAPS * 32]; + +#define xen_feature(flag) (xen_features[flag]) + +#endif /* __ASM_XEN_FEATURES_H__ */ --- /dev/null +++ linus-2.6/drivers/xen/Makefile @@ -0,0 +1,3 @@ + +obj-y += core/ + --- /dev/null +++ linus-2.6/drivers/xen/core/Makefile @@ -0,0 +1,3 @@ + +obj-y := features.o + --- /dev/null +++ linus-2.6/drivers/xen/core/features.c @@ -0,0 +1,29 @@ +/****************************************************************************** + * features.c + * + * Xen feature flags. + * + * Copyright (c) 2006, Ian Campbell, XenSource Inc. + */ +#include +#include +#include +#include +#include + +u8 xen_features[XENFEAT_NR_SUBMAPS * 32] __read_mostly; +EXPORT_SYMBOL_GPL(xen_features); + +void setup_xen_features(void) +{ + struct xen_feature_info fi; + int i, j; + + for (i = 0; i < XENFEAT_NR_SUBMAPS; i++) { + fi.submap_idx = i; + if (HYPERVISOR_xen_version(XENVER_get_features, &fi) < 0) + break; + for (j=0; j<32; j++) + xen_features[i*32+j] = !!(fi.submap & 1<