xref: /openbmc/linux/arch/x86/include/asm/kvm_para.h (revision 9d56dd3b083a3bec56e9da35ce07baca81030b03)
1 #ifndef _ASM_X86_KVM_PARA_H
2 #define _ASM_X86_KVM_PARA_H
3 
4 #include <linux/types.h>
5 
6 /* This CPUID returns the signature 'KVMKVMKVM' in ebx, ecx, and edx.  It
7  * should be used to determine that a VM is running under KVM.
8  */
9 #define KVM_CPUID_SIGNATURE	0x40000000
10 
11 /* This CPUID returns a feature bitmap in eax.  Before enabling a particular
12  * paravirtualization, the appropriate feature bit should be checked.
13  */
14 #define KVM_CPUID_FEATURES	0x40000001
15 #define KVM_FEATURE_CLOCKSOURCE		0
16 #define KVM_FEATURE_NOP_IO_DELAY	1
17 #define KVM_FEATURE_MMU_OP		2
18 
19 #define MSR_KVM_WALL_CLOCK  0x11
20 #define MSR_KVM_SYSTEM_TIME 0x12
21 
22 #define KVM_MAX_MMU_OP_BATCH           32
23 
24 /* Operations for KVM_HC_MMU_OP */
25 #define KVM_MMU_OP_WRITE_PTE            1
26 #define KVM_MMU_OP_FLUSH_TLB	        2
27 #define KVM_MMU_OP_RELEASE_PT	        3
28 
29 /* Payload for KVM_HC_MMU_OP */
30 struct kvm_mmu_op_header {
31 	__u32 op;
32 	__u32 pad;
33 };
34 
35 struct kvm_mmu_op_write_pte {
36 	struct kvm_mmu_op_header header;
37 	__u64 pte_phys;
38 	__u64 pte_val;
39 };
40 
41 struct kvm_mmu_op_flush_tlb {
42 	struct kvm_mmu_op_header header;
43 };
44 
45 struct kvm_mmu_op_release_pt {
46 	struct kvm_mmu_op_header header;
47 	__u64 pt_phys;
48 };
49 
50 #ifdef __KERNEL__
51 #include <asm/processor.h>
52 
53 extern void kvmclock_init(void);
54 
55 
56 /* This instruction is vmcall.  On non-VT architectures, it will generate a
57  * trap that we will then rewrite to the appropriate instruction.
58  */
59 #define KVM_HYPERCALL ".byte 0x0f,0x01,0xc1"
60 
61 /* For KVM hypercalls, a three-byte sequence of either the vmrun or the vmmrun
62  * instruction.  The hypervisor may replace it with something else but only the
63  * instructions are guaranteed to be supported.
64  *
65  * Up to four arguments may be passed in rbx, rcx, rdx, and rsi respectively.
66  * The hypercall number should be placed in rax and the return value will be
67  * placed in rax.  No other registers will be clobbered unless explicited
68  * noted by the particular hypercall.
69  */
70 
71 static inline long kvm_hypercall0(unsigned int nr)
72 {
73 	long ret;
74 	asm volatile(KVM_HYPERCALL
75 		     : "=a"(ret)
76 		     : "a"(nr)
77 		     : "memory");
78 	return ret;
79 }
80 
81 static inline long kvm_hypercall1(unsigned int nr, unsigned long p1)
82 {
83 	long ret;
84 	asm volatile(KVM_HYPERCALL
85 		     : "=a"(ret)
86 		     : "a"(nr), "b"(p1)
87 		     : "memory");
88 	return ret;
89 }
90 
91 static inline long kvm_hypercall2(unsigned int nr, unsigned long p1,
92 				  unsigned long p2)
93 {
94 	long ret;
95 	asm volatile(KVM_HYPERCALL
96 		     : "=a"(ret)
97 		     : "a"(nr), "b"(p1), "c"(p2)
98 		     : "memory");
99 	return ret;
100 }
101 
102 static inline long kvm_hypercall3(unsigned int nr, unsigned long p1,
103 				  unsigned long p2, unsigned long p3)
104 {
105 	long ret;
106 	asm volatile(KVM_HYPERCALL
107 		     : "=a"(ret)
108 		     : "a"(nr), "b"(p1), "c"(p2), "d"(p3)
109 		     : "memory");
110 	return ret;
111 }
112 
113 static inline long kvm_hypercall4(unsigned int nr, unsigned long p1,
114 				  unsigned long p2, unsigned long p3,
115 				  unsigned long p4)
116 {
117 	long ret;
118 	asm volatile(KVM_HYPERCALL
119 		     : "=a"(ret)
120 		     : "a"(nr), "b"(p1), "c"(p2), "d"(p3), "S"(p4)
121 		     : "memory");
122 	return ret;
123 }
124 
125 static inline int kvm_para_available(void)
126 {
127 	unsigned int eax, ebx, ecx, edx;
128 	char signature[13];
129 
130 	cpuid(KVM_CPUID_SIGNATURE, &eax, &ebx, &ecx, &edx);
131 	memcpy(signature + 0, &ebx, 4);
132 	memcpy(signature + 4, &ecx, 4);
133 	memcpy(signature + 8, &edx, 4);
134 	signature[12] = 0;
135 
136 	if (strcmp(signature, "KVMKVMKVM") == 0)
137 		return 1;
138 
139 	return 0;
140 }
141 
142 static inline unsigned int kvm_arch_para_features(void)
143 {
144 	return cpuid_eax(KVM_CPUID_FEATURES);
145 }
146 
147 #endif
148 
149 #endif /* _ASM_X86_KVM_PARA_H */
150