xref: /openbmc/linux/arch/x86/include/asm/kvm_para.h (revision 29d97219)
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 #ifdef CONFIG_KVM_GUEST
11 bool kvm_check_and_clear_guest_paused(void);
12 #else
13 static inline bool kvm_check_and_clear_guest_paused(void)
14 {
15 	return false;
16 }
17 #endif /* CONFIG_KVM_GUEST */
18 
19 #define KVM_HYPERCALL \
20         ALTERNATIVE("vmcall", "vmmcall", X86_FEATURE_VMMCALL)
21 
22 /* For KVM hypercalls, a three-byte sequence of either the vmcall or the vmmcall
23  * instruction.  The hypervisor may replace it with something else but only the
24  * instructions are guaranteed to be supported.
25  *
26  * Up to four arguments may be passed in rbx, rcx, rdx, and rsi respectively.
27  * The hypercall number should be placed in rax and the return value will be
28  * placed in rax.  No other registers will be clobbered unless explicitly
29  * noted by the particular hypercall.
30  */
31 
32 static inline long kvm_hypercall0(unsigned int nr)
33 {
34 	long ret;
35 	asm volatile(KVM_HYPERCALL
36 		     : "=a"(ret)
37 		     : "a"(nr)
38 		     : "memory");
39 	return ret;
40 }
41 
42 static inline long kvm_hypercall1(unsigned int nr, unsigned long p1)
43 {
44 	long ret;
45 	asm volatile(KVM_HYPERCALL
46 		     : "=a"(ret)
47 		     : "a"(nr), "b"(p1)
48 		     : "memory");
49 	return ret;
50 }
51 
52 static inline long kvm_hypercall2(unsigned int nr, unsigned long p1,
53 				  unsigned long p2)
54 {
55 	long ret;
56 	asm volatile(KVM_HYPERCALL
57 		     : "=a"(ret)
58 		     : "a"(nr), "b"(p1), "c"(p2)
59 		     : "memory");
60 	return ret;
61 }
62 
63 static inline long kvm_hypercall3(unsigned int nr, unsigned long p1,
64 				  unsigned long p2, unsigned long p3)
65 {
66 	long ret;
67 	asm volatile(KVM_HYPERCALL
68 		     : "=a"(ret)
69 		     : "a"(nr), "b"(p1), "c"(p2), "d"(p3)
70 		     : "memory");
71 	return ret;
72 }
73 
74 static inline long kvm_hypercall4(unsigned int nr, unsigned long p1,
75 				  unsigned long p2, unsigned long p3,
76 				  unsigned long p4)
77 {
78 	long ret;
79 	asm volatile(KVM_HYPERCALL
80 		     : "=a"(ret)
81 		     : "a"(nr), "b"(p1), "c"(p2), "d"(p3), "S"(p4)
82 		     : "memory");
83 	return ret;
84 }
85 
86 #ifdef CONFIG_KVM_GUEST
87 void kvmclock_init(void);
88 void kvmclock_disable(void);
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 bool __kvm_handle_async_pf(struct pt_regs *regs, u32 token);
96 
97 DECLARE_STATIC_KEY_FALSE(kvm_async_pf_enabled);
98 
99 static __always_inline bool kvm_handle_async_pf(struct pt_regs *regs, u32 token)
100 {
101 	if (static_branch_unlikely(&kvm_async_pf_enabled))
102 		return __kvm_handle_async_pf(regs, token);
103 	else
104 		return false;
105 }
106 
107 #ifdef CONFIG_PARAVIRT_SPINLOCKS
108 void __init kvm_spinlock_init(void);
109 #else /* !CONFIG_PARAVIRT_SPINLOCKS */
110 static inline void kvm_spinlock_init(void)
111 {
112 }
113 #endif /* CONFIG_PARAVIRT_SPINLOCKS */
114 
115 #else /* CONFIG_KVM_GUEST */
116 #define kvm_async_pf_task_wait_schedule(T) do {} while(0)
117 #define kvm_async_pf_task_wake(T) do {} while(0)
118 
119 static inline bool kvm_para_available(void)
120 {
121 	return false;
122 }
123 
124 static inline unsigned int kvm_arch_para_features(void)
125 {
126 	return 0;
127 }
128 
129 static inline unsigned int kvm_arch_para_hints(void)
130 {
131 	return 0;
132 }
133 
134 static inline u32 kvm_read_and_reset_apf_flags(void)
135 {
136 	return 0;
137 }
138 
139 static __always_inline bool kvm_handle_async_pf(struct pt_regs *regs, u32 token)
140 {
141 	return false;
142 }
143 #endif
144 
145 #endif /* _ASM_X86_KVM_PARA_H */
146