Re: [PATCH v2 1/1] target-i386: Fix default Hypervisor level for hypervisor-vendor=kvm.

[Eduardo Habkost <ehabkost@redhat.com>]

On Thu, Sep 20, 2012 at 04:06:27PM -0400, Don Slutz wrote:
> From http://lkml.indiana.edu/hypermail/linux/kernel/1205.0/00100.html
> EAX should be KVM_CPUID_FEATURES (0x40000001) not 0.
> 
> Added hypervisor-vendor=kvm0 to get the older CPUID result. kvm1 selects the newer one.

Why not just make "hypervisor-vendor=kvm" control only the hypervisor
vendor string, and support something like "kvm-hypervisor-level=0" to
restore the old cpuid_hv_level=0 behavior?

This is similar to the kvmclock case: it would allow us to make
"hypervisor-vendor=kvm" use saner values as default, but letting old
machine-types to override it for compatibility if required.

> 
> Signed-off-by: Don Slutz <Don@CloudSwitch.com>
> ---
>  target-i386/cpu.c |   17 +++++++++++++----
>  1 files changed, 13 insertions(+), 4 deletions(-)
> 
> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> index 72a8442..e51b2b1 100644
> --- a/target-i386/cpu.c
> +++ b/target-i386/cpu.c
> @@ -1250,9 +1250,12 @@ static char *x86_cpuid_get_hv_vendor(Object *obj, Error **errp)
>      } else if (!strcmp(value, CPUID_HV_VENDOR_XEN) &&
>                 env->cpuid_hv_level == CPUID_HV_LEVEL_XEN) {
>          pstrcpy(value, sizeof(value), "xen");
> -    } else if (!strcmp(value, CPUID_HV_VENDOR_KVM) &&
> -               env->cpuid_hv_level == 0) {
> -        pstrcpy(value, sizeof(value), "kvm");
> +    } else if (!strcmp(value, CPUID_HV_VENDOR_KVM)) {
> +        if (env->cpuid_hv_level == CPUID_HV_LEVEL_KVM) {
> +            pstrcpy(value, sizeof(value), "kvm1");
> +        } else if (env->cpuid_hv_level == 0) {
> +            pstrcpy(value, sizeof(value), "kvm0");
> +        }
>      }
>      return value;
>  }
> @@ -1288,7 +1291,13 @@ static void x86_cpuid_set_hv_vendor(Object *obj, const char *value,
>              env->cpuid_hv_level = CPUID_HV_LEVEL_XEN;
>          }
>          pstrcpy(adj_value, sizeof(adj_value), CPUID_HV_VENDOR_XEN);
> -    } else if (!strcmp(value, "kvm")) {
> +    } else if (!strcmp(value, "kvm") || !strcmp(value, "kvm1")) {
> +        if (env->cpuid_hv_level == 0) {
> +            env->cpuid_hv_level = CPUID_HV_LEVEL_KVM;
> +        }
> +        pstrcpy(adj_value, sizeof(adj_value), CPUID_HV_VENDOR_KVM);
> +    } else if (!strcmp(value, "kvm0")) {
> +        env->cpuid_hv_level = 0;
>          pstrcpy(adj_value, sizeof(adj_value), CPUID_HV_VENDOR_KVM);
>      } else {
>          pstrcpy(adj_value, sizeof(adj_value), value);
> -- 
> 1.7.1
> 

-- 
Eduardo