drivers/xen/features.c

   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
  13 #include <asm/xen/hypercall.h>
  14
  15 #include <xen/interface/xen.h>
  16 #include <xen/interface/version.h>
  17 #include <xen/features.h>
  18
  19 u8 xen_features[XENFEAT_NR_SUBMAPS * 32] __read_mostly;
  20 EXPORT_SYMBOL_GPL(xen_features);
  21
  22 void xen_setup_features(void)
  23 {
  24         struct xen_feature_info fi;
  25         int i, j;
  26
  27         for (i = 0; i < XENFEAT_NR_SUBMAPS; i++) {
  28                 fi.submap_idx = i;
  29                 if (HYPERVISOR_xen_version(XENVER_get_features, &fi) < 0)
  30                         break;
  31                 for (j = 0; j < 32; j++)
  32                         xen_features[i * 32 + j] = !!(fi.submap & 1<<j);
  33         }
  34 }