diff options
Diffstat (limited to 'include/asm-x86')
-rw-r--r-- | include/asm-x86/kvm_para.h | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/include/asm-x86/kvm_para.h b/include/asm-x86/kvm_para.h new file mode 100644 index 0000000..c6f3fd8 --- /dev/null +++ b/include/asm-x86/kvm_para.h @@ -0,0 +1,105 @@ +#ifndef __X86_KVM_PARA_H +#define __X86_KVM_PARA_H + +/* This CPUID returns the signature 'KVMKVMKVM' in ebx, ecx, and edx. It + * should be used to determine that a VM is running under KVM. + */ +#define KVM_CPUID_SIGNATURE 0x40000000 + +/* This CPUID returns a feature bitmap in eax. Before enabling a particular + * paravirtualization, the appropriate feature bit should be checked. + */ +#define KVM_CPUID_FEATURES 0x40000001 + +#ifdef __KERNEL__ +#include <asm/processor.h> + +/* This instruction is vmcall. On non-VT architectures, it will generate a + * trap that we will then rewrite to the appropriate instruction. + */ +#define KVM_HYPERCALL ".byte 0x0f,0x01,0xc1" + +/* For KVM hypercalls, a three-byte sequence of either the vmrun or the vmmrun + * instruction. The hypervisor may replace it with something else but only the + * instructions are guaranteed to be supported. + * + * Up to four arguments may be passed in rbx, rcx, rdx, and rsi respectively. + * The hypercall number should be placed in rax and the return value will be + * placed in rax. No other registers will be clobbered unless explicited + * noted by the particular hypercall. + */ + +static inline long kvm_hypercall0(unsigned int nr) +{ + long ret; + asm volatile(KVM_HYPERCALL + : "=a"(ret) + : "a"(nr)); + return ret; +} + +static inline long kvm_hypercall1(unsigned int nr, unsigned long p1) +{ + long ret; + asm volatile(KVM_HYPERCALL + : "=a"(ret) + : "a"(nr), "b"(p1)); + return ret; +} + +static inline long kvm_hypercall2(unsigned int nr, unsigned long p1, + unsigned long p2) +{ + long ret; + asm volatile(KVM_HYPERCALL + : "=a"(ret) + : "a"(nr), "b"(p1), "c"(p2)); + return ret; +} + +static inline long kvm_hypercall3(unsigned int nr, unsigned long p1, + unsigned long p2, unsigned long p3) +{ + long ret; + asm volatile(KVM_HYPERCALL + : "=a"(ret) + : "a"(nr), "b"(p1), "c"(p2), "d"(p3)); + return ret; +} + +static inline long kvm_hypercall4(unsigned int nr, unsigned long p1, + unsigned long p2, unsigned long p3, + unsigned long p4) +{ + long ret; + asm volatile(KVM_HYPERCALL + : "=a"(ret) + : "a"(nr), "b"(p1), "c"(p2), "d"(p3), "S"(p4)); + return ret; +} + +static inline int kvm_para_available(void) +{ + unsigned int eax, ebx, ecx, edx; + char signature[13]; + + cpuid(KVM_CPUID_SIGNATURE, &eax, &ebx, &ecx, &edx); + memcpy(signature + 0, &ebx, 4); + memcpy(signature + 4, &ecx, 4); + memcpy(signature + 8, &edx, 4); + signature[12] = 0; + + if (strcmp(signature, "KVMKVMKVM") == 0) + return 1; + + return 0; +} + +static inline unsigned int kvm_arch_para_features(void) +{ + return cpuid_eax(KVM_CPUID_FEATURES); +} + +#endif + +#endif |