cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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features.c (1269B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/******************************************************************************
      3 * features.c
      4 *
      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 guest
     25 * 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}