Re: [Qemu-devel] [PATCH 1/5] KVM: fix coexistence of KVM and Hyper-V leaves

[Marcelo Tosatti <mtosatti@redhat.com>]

On Fri, Jan 24, 2014 at 05:17:52PM +0100, Paolo Bonzini wrote:
> kvm_arch_init_vcpu's initialization of the KVM leaves at 0x40000100
> is broken, because KVM_CPUID_FEATURES is left at 0x40000001.  Move
> it to 0x40000101 if Hyper-V is enabled.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/include/asm/kvm_para.h

static inline unsigned int kvm_arch_para_features(void)
{
        return cpuid_eax(KVM_CPUID_FEATURES);
}

Shouldnt it be using kvm_cpuid_base ?

> ---
>  target-i386/kvm.c | 47 +++++++++++++++++++++++++----------------------
>  1 file changed, 25 insertions(+), 22 deletions(-)
> 
> diff --git a/target-i386/kvm.c b/target-i386/kvm.c
> index 0a21c30..5738911 100644
> --- a/target-i386/kvm.c
> +++ b/target-i386/kvm.c
> @@ -455,6 +455,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
>      uint32_t unused;
>      struct kvm_cpuid_entry2 *c;
>      uint32_t signature[3];
> +    int kvm_base = KVM_CPUID_SIGNATURE;
>      int r;
>  
>      memset(&cpuid_data, 0, sizeof(cpuid_data));
> @@ -462,26 +463,22 @@ int kvm_arch_init_vcpu(CPUState *cs)
>      cpuid_i = 0;
>  
>      /* Paravirtualization CPUIDs */
> -    c = &cpuid_data.entries[cpuid_i++];
> -    c->function = KVM_CPUID_SIGNATURE;
> -    if (!hyperv_enabled(cpu)) {
> -        memcpy(signature, "KVMKVMKVM\0\0\0", 12);
> -        c->eax = 0;
> -    } else {
> +    if (hyperv_enabled(cpu)) {
> +        c = &cpuid_data.entries[cpuid_i++];
> +        c->function = HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS;
>          memcpy(signature, "Microsoft Hv", 12);
>          c->eax = HYPERV_CPUID_MIN;
> -    }
> -    c->ebx = signature[0];
> -    c->ecx = signature[1];
> -    c->edx = signature[2];
> -
> -    c = &cpuid_data.entries[cpuid_i++];
> -    c->function = KVM_CPUID_FEATURES;
> -    c->eax = env->features[FEAT_KVM];
> +        c->ebx = signature[0];
> +        c->ecx = signature[1];
> +        c->edx = signature[2];
>  
> -    if (hyperv_enabled(cpu)) {
> +        c = &cpuid_data.entries[cpuid_i++];
> +        c->function = HYPERV_CPUID_INTERFACE;
>          memcpy(signature, "Hv#1\0\0\0\0\0\0\0\0", 12);
>          c->eax = signature[0];
> +        c->ebx = 0;
> +        c->ecx = 0;
> +        c->edx = 0;
>  
>          c = &cpuid_data.entries[cpuid_i++];
>          c->function = HYPERV_CPUID_VERSION;
> @@ -513,15 +510,21 @@ int kvm_arch_init_vcpu(CPUState *cs)
>          c->eax = 0x40;
>          c->ebx = 0x40;
>  
> -        c = &cpuid_data.entries[cpuid_i++];
> -        c->function = KVM_CPUID_SIGNATURE_NEXT;
> -        memcpy(signature, "KVMKVMKVM\0\0\0", 12);
> -        c->eax = 0;
> -        c->ebx = signature[0];
> -        c->ecx = signature[1];
> -        c->edx = signature[2];
> +        kvm_base = KVM_CPUID_SIGNATURE_NEXT;
>      }
>  
> +    memcpy(signature, "KVMKVMKVM\0\0\0", 12);
> +    c = &cpuid_data.entries[cpuid_i++];
> +    c->function = KVM_CPUID_SIGNATURE | kvm_base;
> +    c->eax = 0;
> +    c->ebx = signature[0];
> +    c->ecx = signature[1];
> +    c->edx = signature[2];
> +
> +    c = &cpuid_data.entries[cpuid_i++];
> +    c->function = KVM_CPUID_FEATURES | kvm_base;
> +    c->eax = env->features[FEAT_KVM];
> +
>      has_msr_async_pf_en = c->eax & (1 << KVM_FEATURE_ASYNC_PF);
>  
>      has_msr_pv_eoi_en = c->eax & (1 << KVM_FEATURE_PV_EOI);
> -- 
> 1.8.3.1
>