Re: [Qemu-devel] [PATCH v6 06/16] target-i386: Use Hypervisor level in -machine pc, accel=tcg.

[Marcelo Tosatti]

On Mon, Sep 24, 2012 at 10:32:08AM -0400, Don Slutz wrote:
> Also known as Paravirtualization level.
> 
> This change is based on:
> 
> Microsoft Hypervisor CPUID Leaves:
>   
> http://msdn.microsoft.com/en-us/library/windows/hardware/ff542428%28v=vs.85%29.aspx
> 
> Linux kernel change starts with:
>   http://fixunix.com/kernel/538707-use-cpuid-communicate-hypervisor.html
> Also:
>   http://lkml.indiana.edu/hypermail/linux/kernel/1205.0/00100.html
> 
> VMware documention on CPUIDs (Mechanisms to determine if software is
> running in a VMware virtual machine):
>   
> http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1009458
> 
> QEMU knows this as KVM_CPUID_SIGNATURE (0x40000000) in kvm on linux.
> 
> This does not provide vendor support in tcg yet.
> 
> Signed-off-by: Don Slutz <address@hidden>
> ---
>  target-i386/cpu.c |   27 +++++++++++++++++++++++++++
>  1 files changed, 27 insertions(+), 0 deletions(-)
> 
> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> index 48bdaf9..920278b 100644
> --- a/target-i386/cpu.c
> +++ b/target-i386/cpu.c
> @@ -1651,6 +1651,21 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, 
> uint32_t count,
>                  index =  env->cpuid_xlevel;
>              }
>          }
> +    } else if (index & 0x40000000) {
> +        if (env->cpuid_hv_level_set) {
> +            uint32_t real_level = env->cpuid_hv_level;
> +
> +            /* Handle Hypervisor CPUIDs */
> +            if (real_level < 0x40000000) {
> +                real_level = 0x40000000;
> +            }
> +            if (index > real_level) {
> +                index = real_level;
> +            }
> +        } else {
> +            if (index > env->cpuid_level)
> +                index = env->cpuid_level;
> +        }

Whats the purpose of this checks?

Please provide changelogs for each patch.

>      } else {
>          if (index > env->cpuid_level)
>              index = env->cpuid_level;
> @@ -1789,6 +1804,18 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, 
> uint32_t count,
>              *edx = 0;
>          }
>          break;
> +    case 0x40000000:
> +        *eax = env->cpuid_hv_level;
> +        *ebx = 0;
> +        *ecx = 0;
> +        *edx = 0;
> +        break;
> +    case 0x40000001:
> +        *eax = env->cpuid_kvm_features;
> +        *ebx = 0;
> +        *ecx = 0;
> +        *edx = 0;
> +        break;
>      case 0x80000000:
>          *eax = env->cpuid_xlevel;
>          *ebx = env->cpuid_vendor1;
> -- 
> 1.7.1
> 
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