arch/x86/include/asm/xen/hypervisor.h

   1 /******************************************************************************
   2  * hypervisor.h
   3  *
   4  * Linux-specific hypervisor handling.
   5  *
   6  * Copyright (c) 2002-2004, K A Fraser
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License version 2
  10  * as published by the Free Software Foundation; or, when distributed
  11  * separately from the Linux kernel or incorporated into other
  12  * software packages, subject to the following license:
  13  *
  14  * Permission is hereby granted, free of charge, to any person obtaining a copy
  15  * of this source file (the "Software"), to deal in the Software without
  16  * restriction, including without limitation the rights to use, copy, modify,
  17  * merge, publish, distribute, sublicense, and/or sell copies of the Software,
  18  * and to permit persons to whom the Software is furnished to do so, subject to
  19  * the following conditions:
  20  *
  21  * The above copyright notice and this permission notice shall be included in
  22  * all copies or substantial portions of the Software.
  23  *
  24  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  25  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  26  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  27  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  28  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  29  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  30  * IN THE SOFTWARE.
  31  */
  32
  33 #ifndef _ASM_X86_XEN_HYPERVISOR_H
  34 #define _ASM_X86_XEN_HYPERVISOR_H
  35
  36 /* arch/i386/kernel/setup.c */
  37 extern struct shared_info *HYPERVISOR_shared_info;
  38 extern struct start_info *xen_start_info;
  39
  40 #include <asm/processor.h>
  41
  42 static inline uint32_t xen_cpuid_base(void)
  43 {
  44         uint32_t base, eax, ebx, ecx, edx;
  45         char signature[13];
  46
  47         for (base = 0x40000000; base < 0x40010000; base += 0x100) {
  48                 cpuid(base, &eax, &ebx, &ecx, &edx);
  49                 *(uint32_t *)(signature + 0) = ebx;
  50                 *(uint32_t *)(signature + 4) = ecx;
  51                 *(uint32_t *)(signature + 8) = edx;
  52                 signature[12] = 0;
  53
  54                 if (!strcmp("XenVMMXenVMM", signature) && ((eax - base) >= 2))
  55                         return base;
  56         }
  57
  58         return 0;
  59 }
  60
  61 #ifdef CONFIG_XEN
  62 extern bool xen_hvm_need_lapic(void);
  63
  64 static inline bool xen_x2apic_para_available(void)
  65 {
  66         return xen_hvm_need_lapic();
  67 }
  68 #else
  69 static inline bool xen_x2apic_para_available(void)
  70 {
  71         return (xen_cpuid_base() != 0);
  72 }
  73 #endif
  74
  75 #endif /* _ASM_X86_XEN_HYPERVISOR_H */