Re: [PATCH/RFC] Per-architecture hypercall definitions

[Anthony Liguori <anthony-rdkfGonbjUSkNkDKm+mE6A@public.gmane.org>]

Christian Borntraeger wrote:
>
> I agree. It seems I can simply remove the kvm_hypercall macro.
>
> Here is the updated patch (without the s390 parts. Will send them later
> when ready) and the changes mentioned above.
>
> Avi, Anthony, comments?
>   

It looks good to me.

Regards,

Anthony Liguori

> [PATCH/RFC] Per-architecture hypercall definitions
>
> Currently kvm provides hypercalls only for x86* architectures. To
> provide hypercall infrastructure for other kvm architectures I split
> kvm_para.h into a generic header file and architecture specific
> definitions.
>
> Signed-off-by: Christian Borntraeger <borntraeger-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org>
>
> Index: kvm/include/asm-x86/kvm_para.h
> ===================================================================
> --- /dev/null	1970-01-01 00:00:00.000000000 +0000
> +++ kvm/include/asm-x86/kvm_para.h	2007-10-11 15:41:24.000000000 +0200
> @@ -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
> Index: kvm/include/linux/kvm_para.h
> ===================================================================
> --- kvm.orig/include/linux/kvm_para.h	2007-10-11 13:28:46.000000000 +0200
> +++ kvm/include/linux/kvm_para.h	2007-10-11 15:41:53.000000000 +0200
> @@ -1,110 +1,29 @@
>  #ifndef __LINUX_KVM_PARA_H
>  #define __LINUX_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.
> +/*
> + * This header file provides a method for making a hypercall to the host
> + * Architectures should define:
> + * - kvm_hypercall0, kvm_hypercall1...
> + * - kvm_arch_para_features
> + * - kvm_para_available
>   */
> -#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
>  
>  /* Return values for hypercalls */
>  #define KVM_ENOSYS		1000
>  
>  #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.
> +/*
> + * hypercalls use architecture specific
>   */
> -
> -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;
> -}
> +#include <asm/kvm_para.h>
>  
>  static inline int kvm_para_has_feature(unsigned int feature)
>  {
> -	if (cpuid_eax(KVM_CPUID_FEATURES) & (1UL << feature))
> +	if (kvm_arch_para_features() & (1UL << feature))
>  		return 1;
>  	return 0;
>  }
> +#endif /* __KERNEL__ */
> +#endif /* __LINUX_KVM_PARA_H */
>  
> -#endif
> -
> -#endif
>
>
>
>   


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