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1// SPDX-License-Identifier: GPL-2.0-only2/******************************************************************************3 * features.c4 *5 * Xen feature flags.6 *7 * Copyright (c) 2006, Ian Campbell, XenSource Inc.8 */9#include <linux/types.h>10#include <linux/cache.h>11#include <linux/export.h>12#include <linux/printk.h>13 14#include <asm/xen/hypercall.h>15 16#include <xen/xen.h>17#include <xen/interface/xen.h>18#include <xen/interface/version.h>19#include <xen/features.h>20 21/*22 * Linux kernel expects at least Xen 4.0.23 *24 * Assume some features to be available for that reason (depending on guest25 * mode, of course).26 */27#define chk_required_feature(f) { \28 if (!xen_feature(f)) \29 panic("Xen: feature %s not available!\n", #f); \30 }31 32u8 xen_features[XENFEAT_NR_SUBMAPS * 32] __read_mostly;33EXPORT_SYMBOL_GPL(xen_features);34 35void xen_setup_features(void)36{37 struct xen_feature_info fi;38 int i, j;39 40 for (i = 0; i < XENFEAT_NR_SUBMAPS; i++) {41 fi.submap_idx = i;42 if (HYPERVISOR_xen_version(XENVER_get_features, &fi) < 0)43 break;44 for (j = 0; j < 32; j++)45 xen_features[i * 32 + j] = !!(fi.submap & 1U << j);46 }47 48 if (xen_pv_domain()) {49 chk_required_feature(XENFEAT_mmu_pt_update_preserve_ad);50 chk_required_feature(XENFEAT_gnttab_map_avail_bits);51 }52}53