Re: [PATCH RFC 04/22] i386: move hyperv_interface_id initialization to x86_cpu_realizefn()

[Eduardo Habkost <ehabkost@redhat.com>]

On Fri, Sep 04, 2020 at 04:54:13PM +0200, Vitaly Kuznetsov wrote:
> As a preparation to expanding Hyper-V CPU features early, move
> hyperv_interface_id initialization to x86_cpu_realizefn().
> 
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> ---
>  target/i386/cpu.c |  6 ++++++
>  target/i386/cpu.h |  1 +
>  target/i386/kvm.c | 18 ++++++++++++------
>  3 files changed, 19 insertions(+), 6 deletions(-)
> 
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index 07e9da9e567e..16888125a30a 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -6638,6 +6638,12 @@ static void x86_cpu_realizefn(DeviceState *dev, Error **errp)
>          memcpy(cpu->hyperv_vendor_id, cpu->hyperv_vendor, len);
>      }
>  
> +    /* 'Hv#1' interface identification*/
> +    cpu->hyperv_interface_id[0] = 0x31237648;
> +    cpu->hyperv_interface_id[1] = 0;
> +    cpu->hyperv_interface_id[2] = 0;
> +    cpu->hyperv_interface_id[3] = 0;
> +
>      if (cpu->ucode_rev == 0) {
>          /* The default is the same as KVM's.  */
>          if (IS_AMD_CPU(env)) {
> diff --git a/target/i386/cpu.h b/target/i386/cpu.h
> index 903994818093..91edc54a268c 100644
> --- a/target/i386/cpu.h
> +++ b/target/i386/cpu.h
> @@ -1660,6 +1660,7 @@ struct X86CPU {
>      bool hyperv_passthrough;
>      OnOffAuto hyperv_no_nonarch_cs;
>      uint32_t hyperv_vendor_id[3];
> +    uint32_t hyperv_interface_id[4];
>  
>      bool check_cpuid;
>      bool enforce_cpuid;
> diff --git a/target/i386/kvm.c b/target/i386/kvm.c
> index 47779c5e1efd..a36c65100cd0 100644
> --- a/target/i386/kvm.c
> +++ b/target/i386/kvm.c
> @@ -1188,7 +1188,6 @@ static int hyperv_handle_properties(CPUState *cs,
>      CPUX86State *env = &cpu->env;
>      struct kvm_cpuid2 *cpuid;
>      struct kvm_cpuid_entry2 *c;
> -    uint32_t signature[3];
>      uint32_t cpuid_i = 0;
>      int r;
>  
> @@ -1232,6 +1231,14 @@ static int hyperv_handle_properties(CPUState *cs,
>              cpu->hyperv_vendor_id[2] = c->edx;
>          }
>  
> +        c = cpuid_find_entry(cpuid, HV_CPUID_INTERFACE, 0);
> +        if (c) {
> +            cpu->hyperv_interface_id[0] = c->eax;
> +            cpu->hyperv_interface_id[1] = c->ebx;
> +            cpu->hyperv_interface_id[2] = c->ecx;
> +            cpu->hyperv_interface_id[3] = c->edx;
> +        }
> +

Same question I sent for vendor id, version id, hyperv_limits:
should this go to a separate patch, as it changes behavior of
hv-passthrough?

>          c = cpuid_find_entry(cpuid, HV_CPUID_FEATURES, 0);
>          if (c) {
>              env->features[FEAT_HYPERV_EAX] = c->eax;
> @@ -1314,11 +1321,10 @@ static int hyperv_handle_properties(CPUState *cs,
>  
>      c = &cpuid_ent[cpuid_i++];
>      c->function = HV_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->eax = cpu->hyperv_interface_id[0];
> +    c->ebx = cpu->hyperv_interface_id[1];
> +    c->ecx = cpu->hyperv_interface_id[2];
> +    c->edx = cpu->hyperv_interface_id[3];
>  
>      c = &cpuid_ent[cpuid_i++];
>      c->function = HV_CPUID_VERSION;
> -- 
> 2.25.4
> 

-- 
Eduardo