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hypervisor.h
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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 extern struct shared_info *HYPERVISOR_shared_info;
37 extern struct start_info *xen_start_info;
38 
39 #include <asm/processor.h>
40 
41 static inline uint32_t xen_cpuid_base(void)
42 {
43  uint32_t base, eax, ebx, ecx, edx;
44  char signature[13];
45 
46  for (base = 0x40000000; base < 0x40010000; base += 0x100) {
47  cpuid(base, &eax, &ebx, &ecx, &edx);
48  *(uint32_t *)(signature + 0) = ebx;
49  *(uint32_t *)(signature + 4) = ecx;
50  *(uint32_t *)(signature + 8) = edx;
51  signature[12] = 0;
52 
53  if (!strcmp("XenVMMXenVMM", signature) && ((eax - base) >= 2))
54  return base;
55  }
56 
57  return 0;
58 }
59 
60 #ifdef CONFIG_XEN
61 extern bool xen_hvm_need_lapic(void);
62 
63 static inline bool xen_x2apic_para_available(void)
64 {
65  return xen_hvm_need_lapic();
66 }
67 #else
68 static inline bool xen_x2apic_para_available(void)
69 {
70  return (xen_cpuid_base() != 0);
71 }
72 #endif
73 
74 #endif /* _ASM_X86_XEN_HYPERVISOR_H */