xref: /openbmc/linux/arch/x86/include/asm/kvm_para.h (revision b4e18b29)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_X86_KVM_PARA_H
3 #define _ASM_X86_KVM_PARA_H
4 
5 #include <asm/processor.h>
6 #include <asm/alternative.h>
7 #include <linux/interrupt.h>
8 #include <uapi/asm/kvm_para.h>
9 
10 extern void kvmclock_init(void);
11 
12 #ifdef CONFIG_KVM_GUEST
13 bool kvm_check_and_clear_guest_paused(void);
14 #else
15 static inline bool kvm_check_and_clear_guest_paused(void)
16 {
17 	return false;
18 }
19 #endif /* CONFIG_KVM_GUEST */
20 
21 #define KVM_HYPERCALL \
22         ALTERNATIVE("vmcall", "vmmcall", X86_FEATURE_VMMCALL)
23 
24 /* For KVM hypercalls, a three-byte sequence of either the vmcall or the vmmcall
25  * instruction.  The hypervisor may replace it with something else but only the
26  * instructions are guaranteed to be supported.
27  *
28  * Up to four arguments may be passed in rbx, rcx, rdx, and rsi respectively.
29  * The hypercall number should be placed in rax and the return value will be
30  * placed in rax.  No other registers will be clobbered unless explicitly
31  * noted by the particular hypercall.
32  */
33 
34 static inline long kvm_hypercall0(unsigned int nr)
35 {
36 	long ret;
37 	asm volatile(KVM_HYPERCALL
38 		     : "=a"(ret)
39 		     : "a"(nr)
40 		     : "memory");
41 	return ret;
42 }
43 
44 static inline long kvm_hypercall1(unsigned int nr, unsigned long p1)
45 {
46 	long ret;
47 	asm volatile(KVM_HYPERCALL
48 		     : "=a"(ret)
49 		     : "a"(nr), "b"(p1)
50 		     : "memory");
51 	return ret;
52 }
53 
54 static inline long kvm_hypercall2(unsigned int nr, unsigned long p1,
55 				  unsigned long p2)
56 {
57 	long ret;
58 	asm volatile(KVM_HYPERCALL
59 		     : "=a"(ret)
60 		     : "a"(nr), "b"(p1), "c"(p2)
61 		     : "memory");
62 	return ret;
63 }
64 
65 static inline long kvm_hypercall3(unsigned int nr, unsigned long p1,
66 				  unsigned long p2, unsigned long p3)
67 {
68 	long ret;
69 	asm volatile(KVM_HYPERCALL
70 		     : "=a"(ret)
71 		     : "a"(nr), "b"(p1), "c"(p2), "d"(p3)
72 		     : "memory");
73 	return ret;
74 }
75 
76 static inline long kvm_hypercall4(unsigned int nr, unsigned long p1,
77 				  unsigned long p2, unsigned long p3,
78 				  unsigned long p4)
79 {
80 	long ret;
81 	asm volatile(KVM_HYPERCALL
82 		     : "=a"(ret)
83 		     : "a"(nr), "b"(p1), "c"(p2), "d"(p3), "S"(p4)
84 		     : "memory");
85 	return ret;
86 }
87 
88 #ifdef CONFIG_KVM_GUEST
89 bool kvm_para_available(void);
90 unsigned int kvm_arch_para_features(void);
91 unsigned int kvm_arch_para_hints(void);
92 void kvm_async_pf_task_wait_schedule(u32 token);
93 void kvm_async_pf_task_wake(u32 token);
94 u32 kvm_read_and_reset_apf_flags(void);
95 void kvm_disable_steal_time(void);
96 bool __kvm_handle_async_pf(struct pt_regs *regs, u32 token);
97 
98 DECLARE_STATIC_KEY_FALSE(kvm_async_pf_enabled);
99 
100 static __always_inline bool kvm_handle_async_pf(struct pt_regs *regs, u32 token)
101 {
102 	if (static_branch_unlikely(&kvm_async_pf_enabled))
103 		return __kvm_handle_async_pf(regs, token);
104 	else
105 		return false;
106 }
107 
108 #ifdef CONFIG_PARAVIRT_SPINLOCKS
109 void __init kvm_spinlock_init(void);
110 #else /* !CONFIG_PARAVIRT_SPINLOCKS */
111 static inline void kvm_spinlock_init(void)
112 {
113 }
114 #endif /* CONFIG_PARAVIRT_SPINLOCKS */
115 
116 #else /* CONFIG_KVM_GUEST */
117 #define kvm_async_pf_task_wait_schedule(T) do {} while(0)
118 #define kvm_async_pf_task_wake(T) do {} while(0)
119 
120 static inline bool kvm_para_available(void)
121 {
122 	return false;
123 }
124 
125 static inline unsigned int kvm_arch_para_features(void)
126 {
127 	return 0;
128 }
129 
130 static inline unsigned int kvm_arch_para_hints(void)
131 {
132 	return 0;
133 }
134 
135 static inline u32 kvm_read_and_reset_apf_flags(void)
136 {
137 	return 0;
138 }
139 
140 static inline void kvm_disable_steal_time(void)
141 {
142 	return;
143 }
144 
145 static __always_inline bool kvm_handle_async_pf(struct pt_regs *regs, u32 token)
146 {
147 	return false;
148 }
149 #endif
150 
151 #endif /* _ASM_X86_KVM_PARA_H */
152