1 #ifndef __X86_KVM_PARA_H
2 #define __X86_KVM_PARA_H
4 /* This CPUID returns the signature 'KVMKVMKVM' in ebx, ecx, and edx. It
5 * should be used to determine that a VM is running under KVM.
7 #define KVM_CPUID_SIGNATURE 0x40000000
9 /* This CPUID returns a feature bitmap in eax. Before enabling a particular
10 * paravirtualization, the appropriate feature bit should be checked.
12 #define KVM_CPUID_FEATURES 0x40000001
15 #include <asm/processor.h>
17 /* This instruction is vmcall. On non-VT architectures, it will generate a
18 * trap that we will then rewrite to the appropriate instruction.
20 #define KVM_HYPERCALL ".byte 0x0f,0x01,0xc1"
22 /* For KVM hypercalls, a three-byte sequence of either the vmrun or the vmmrun
23 * instruction. The hypervisor may replace it with something else but only the
24 * instructions are guaranteed to be supported.
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 explicited
29 * noted by the particular hypercall.
32 static inline long kvm_hypercall0(unsigned int nr)
35 asm volatile(KVM_HYPERCALL
41 static inline long kvm_hypercall1(unsigned int nr, unsigned long p1)
44 asm volatile(KVM_HYPERCALL
50 static inline long kvm_hypercall2(unsigned int nr, unsigned long p1,
54 asm volatile(KVM_HYPERCALL
56 : "a"(nr), "b"(p1), "c"(p2));
60 static inline long kvm_hypercall3(unsigned int nr, unsigned long p1,
61 unsigned long p2, unsigned long p3)
64 asm volatile(KVM_HYPERCALL
66 : "a"(nr), "b"(p1), "c"(p2), "d"(p3));
70 static inline long kvm_hypercall4(unsigned int nr, unsigned long p1,
71 unsigned long p2, unsigned long p3,
75 asm volatile(KVM_HYPERCALL
77 : "a"(nr), "b"(p1), "c"(p2), "d"(p3), "S"(p4));
81 static inline int kvm_para_available(void)
83 unsigned int eax, ebx, ecx, edx;
86 cpuid(KVM_CPUID_SIGNATURE, &eax, &ebx, &ecx, &edx);
87 memcpy(signature + 0, &ebx, 4);
88 memcpy(signature + 4, &ecx, 4);
89 memcpy(signature + 8, &edx, 4);
92 if (strcmp(signature, "KVMKVMKVM") == 0)
98 static inline unsigned int kvm_arch_para_features(void)
100 return cpuid_eax(KVM_CPUID_FEATURES);