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// SPDX-License-Identifier: GPL-2.0-only/****************************************************************************** * features.c * * Xen feature flags. * * Copyright (c) 2006, Ian Campbell, XenSource Inc. */#include <linux/types.h>#include <linux/cache.h>#include <linux/export.h>#include <linux/printk.h> #include <asm/xen/hypercall.h> #include <xen/xen.h>#include <xen/interface/xen.h>#include <xen/interface/version.h>#include <xen/features.h> /* * Linux kernel expects at least Xen 4.0. * * Assume some features to be available for that reason (depending on guest * mode, of course). */#define chk_required_feature(f) {					\		if (!xen_feature(f))					\			panic("Xen: feature %s not available!\n", #f);	\	} u8 xen_features[XENFEAT_NR_SUBMAPS * 32] __read_mostly;EXPORT_SYMBOL_GPL(xen_features); void xen_setup_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 & 1U << j);	} 	if (xen_pv_domain()) {		chk_required_feature(XENFEAT_mmu_pt_update_preserve_ad);		chk_required_feature(XENFEAT_gnttab_map_avail_bits);	}}