[libvirt] [PATCH 2/4] configure: remove check for CPUID

[Daniel P. Berrange]

On Wed, Dec 07, 2016 at 04:08:12PM +0100, Pavel Hrdina wrote:
> This check is not required because all i386 and x86_64 cpus have the
> cpuid instruction.

Technically cpuid was only introduced in i486 cpus or later. Of course
no one is going to be running libvirt on anything older than an i686,
so for the real world we're fine with this simplification.

> 
> Signed-off-by: Pavel Hrdina <phrdina at redhat.com>
> ---
>  configure.ac      | 19 -------------------
>  src/cpu/cpu_x86.c |  4 ++--
>  2 files changed, 2 insertions(+), 21 deletions(-)
> 
> diff --git a/configure.ac b/configure.ac
> index 6f04bdc1f6..3b129e0207 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -265,25 +265,6 @@ LIBVIRT_CHECK_NSS
>  LIBVIRT_CHECK_YAJL
>  LIBVIRT_CHECK_GNUTLS
>  
> -AC_MSG_CHECKING([for CPUID instruction])
> -AC_COMPILE_IFELSE([AC_LANG_PROGRAM(
> -  [[
> -    #include <stdint.h>
> -  ]],
> -  [[
> -    uint32_t eax, ebx, ecx, edx;
> -    asm volatile (
> -        "cpuid"
> -        : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx)
> -        : "a" (eax));
> -  ]])],
> -  [have_cpuid=yes],
> -  [have_cpuid=no])
> -if test "x$have_cpuid" = xyes; then
> -  AC_DEFINE_UNQUOTED([HAVE_CPUID], 1, [whether CPUID instruction is supported])
> -fi
> -AC_MSG_RESULT([$have_cpuid])
> -
>  AC_CHECK_SIZEOF([long])
>  
>  dnl Availability of various common functions (non-fatal if missing),
> diff --git a/src/cpu/cpu_x86.c b/src/cpu/cpu_x86.c
> index c79308a715..23a519ec00 100644
> --- a/src/cpu/cpu_x86.c
> +++ b/src/cpu/cpu_x86.c
> @@ -2058,7 +2058,7 @@ x86Encode(virArch arch,
>  }
>  
>  
> -#if HAVE_CPUID
> +#if defined(__i386__) || defined(__x86_64__)
>  static inline void
>  cpuidCall(virCPUx86CPUID *cpuid)
>  {
> @@ -2740,7 +2740,7 @@ struct cpuArchDriver cpuDriverX86 = {
>      .decode     = x86DecodeCPUData,
>      .encode     = x86Encode,
>      .free       = x86FreeCPUData,
> -#if HAVE_CPUID
> +#if defined(__i386__) || defined(__x86_64__)
>      .nodeData   = x86NodeData,
>  #else
>      .nodeData   = NULL,

ACK


Regards,
Daniel
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