target-i386/hyperv.c

   1 /*
   2  * QEMU Hyper-V support
   3  *
   4  * Copyright Red Hat, Inc. 2011
   5  *
   6  * Author: Vadim Rozenfeld     <vrozenfe@redhat.com>
   7  *
   8  * This work is licensed under the terms of the GNU GPL, version 2 or later.
   9  * See the COPYING file in the top-level directory.
  10  *
  11  */
  12
  13 #include "hyperv.h"
  14
  15 static bool hyperv_vapic;
  16 static bool hyperv_relaxed_timing;
  17 static int hyperv_spinlock_attempts = HYPERV_SPINLOCK_NEVER_RETRY;
  18
  19 void hyperv_enable_vapic_recommended(bool val)
  20 {
  21     hyperv_vapic = val;
  22 }
  23
  24 void hyperv_enable_relaxed_timing(bool val)
  25 {
  26     hyperv_relaxed_timing = val;
  27 }
  28
  29 void hyperv_set_spinlock_retries(int val)
  30 {
  31     hyperv_spinlock_attempts = val;
  32     if (hyperv_spinlock_attempts < 0xFFF) {
  33         hyperv_spinlock_attempts = 0xFFF;
  34     }
  35 }
  36
  37 bool hyperv_enabled(void)
  38 {
  39     return hyperv_hypercall_available() || hyperv_relaxed_timing_enabled();
  40 }
  41
  42 bool hyperv_hypercall_available(void)
  43 {
  44     if (hyperv_vapic ||
  45         (hyperv_spinlock_attempts != HYPERV_SPINLOCK_NEVER_RETRY)) {
  46       return true;
  47     }
  48     return false;
  49 }
  50
  51 bool hyperv_vapic_recommended(void)
  52 {
  53     return hyperv_vapic;
  54 }
  55
  56 bool hyperv_relaxed_timing_enabled(void)
  57 {
  58     return hyperv_relaxed_timing;
  59 }
  60
  61 int hyperv_get_spinlock_retries(void)
  62 {
  63     return hyperv_spinlock_attempts;
  64 }