Re: [Qemu-devel] [RESEND PATCH] kvm: Allow the Hyper-V vendor ID to be specified

[Paolo Bonzini <pbonzini@redhat.com>]

On 16/10/2015 00:16, Alex Williamson wrote:
> According to Microsoft documentation, the signature in the standard
> hypervisor CPUID leaf at 0x40000000 identifies the Vendor ID and is
> for reporting and diagnostic purposes only.  We can therefore allow
> the user to change it to whatever they want, within the 12 character
> limit.  Add a new hyperv-vendor-id option to the -cpu flag to allow
> for this, ex:
> 
>  -cpu host,hv_time,hv_vendor_id=KeenlyKVM
> 
> Link: http://msdn.microsoft.com/library/windows/hardware/hh975392
> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
> ---
> 
> Cc'ing get_maintainers this time.  Any takers?  Thanks,
> Alex
> 
>  target-i386/cpu-qom.h |    1 +
>  target-i386/cpu.c     |    1 +
>  target-i386/kvm.c     |   14 +++++++++++++-
>  3 files changed, 15 insertions(+), 1 deletion(-)
> 
> diff --git a/target-i386/cpu-qom.h b/target-i386/cpu-qom.h
> index c35b624..6c1eaaa 100644
> --- a/target-i386/cpu-qom.h
> +++ b/target-i386/cpu-qom.h
> @@ -88,6 +88,7 @@ typedef struct X86CPU {
>      bool hyperv_vapic;
>      bool hyperv_relaxed_timing;
>      int hyperv_spinlock_attempts;
> +    char *hyperv_vendor_id;
>      bool hyperv_time;
>      bool hyperv_crash;
>      bool check_cpuid;
> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> index 05d7f26..71df546 100644
> --- a/target-i386/cpu.c
> +++ b/target-i386/cpu.c
> @@ -3146,6 +3146,7 @@ static Property x86_cpu_properties[] = {
>      DEFINE_PROP_UINT32("level", X86CPU, env.cpuid_level, 0),
>      DEFINE_PROP_UINT32("xlevel", X86CPU, env.cpuid_xlevel, 0),
>      DEFINE_PROP_UINT32("xlevel2", X86CPU, env.cpuid_xlevel2, 0),
> +    DEFINE_PROP_STRING("hv-vendor-id", X86CPU, hyperv_vendor_id),
>      DEFINE_PROP_END_OF_LIST()
>  };
>  
> diff --git a/target-i386/kvm.c b/target-i386/kvm.c
> index 80d1a7e..5e3ab22 100644
> --- a/target-i386/kvm.c
> +++ b/target-i386/kvm.c
> @@ -490,7 +490,19 @@ int kvm_arch_init_vcpu(CPUState *cs)
>      if (hyperv_enabled(cpu)) {
>          c = &cpuid_data.entries[cpuid_i++];
>          c->function = HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS;
> -        memcpy(signature, "Microsoft Hv", 12);
> +        if (!cpu->hyperv_vendor_id) {
> +            memcpy(signature, "Microsoft Hv", 12);
> +        } else {
> +            size_t len = strlen(cpu->hyperv_vendor_id);
> +
> +            if (len > 12) {
> +                fprintf(stderr,
> +                        "hyperv-vendor-id too long, limited to 12 charaters");
> +                abort();

I'm removing this abort and queueing the patch.  I'll send a pull
request today.

Paolo

> +            }
> +            memset(signature, 0, 12);
> +            memcpy(signature, cpu->hyperv_vendor_id, len);
> +        }
>          c->eax = HYPERV_CPUID_MIN;
>          c->ebx = signature[0];
>          c->ecx = signature[1];
> 
> --
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