Re: [Qemu-devel] [PATCH v3 6/9] i386/cpu: Add CPUID.1F generation support for multi-dies PCMachine

[Eduardo Habkost]

On Wed, Jun 12, 2019 at 04:41:01PM +0800, Like Xu wrote:
> The CPUID.1F as Intel V2 Extended Topology Enumeration Leaf would be
> exposed if guests want to emulate multiple software-visible die within
> each package. Per Intel's SDM, the 0x1f is a superset of 0xb, thus they
> can be generated by almost same code as 0xb except die_offset setting.
> 
> If the number of dies per package is less than 2, the qemu will not
> expose CPUID.1F regardless of whether the host supports CPUID.1F.
> 
> Signed-off-by: Like Xu <address@hidden>

Reviewed-by: Eduardo Habkost <address@hidden>

> ---
>  target/i386/cpu.c | 37 +++++++++++++++++++++++++++++++++++++
>  target/i386/cpu.h |  4 ++++
>  target/i386/kvm.c | 12 ++++++++++++
>  3 files changed, 53 insertions(+)
> 
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index 09e20a2c3b..127aff74a6 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -4437,6 +4437,42 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, 
> uint32_t count,
>              *ecx |= CPUID_TOPOLOGY_LEVEL_INVALID;
>          }
>  
> +        assert(!(*eax & ~0x1f));
> +        *ebx &= 0xffff; /* The count doesn't need to be reliable. */
> +        break;
> +    case 0x1F:
> +        /* V2 Extended Topology Enumeration Leaf */
> +        if (env->nr_dies < 2 || !cpu->enable_cpuid_0x1f) {
> +            *eax = *ebx = *ecx = *edx = 0;
> +            break;
> +        }
> +
> +        *ecx = count & 0xff;
> +        *edx = cpu->apic_id;
> +        switch (count) {
> +        case 0:
> +            *eax = apicid_core_offset(env->nr_dies, cs->nr_cores,
> +                                                    cs->nr_threads);
> +            *ebx = cs->nr_threads;
> +            *ecx |= CPUID_TOPOLOGY_LEVEL_SMT;
> +            break;
> +        case 1:
> +            *eax = apicid_die_offset(env->nr_dies, cs->nr_cores,
> +                                                   cs->nr_threads);
> +            *ebx = cs->nr_cores * cs->nr_threads;
> +            *ecx |= CPUID_TOPOLOGY_LEVEL_CORE;
> +            break;
> +        case 2:
> +            *eax = apicid_pkg_offset(env->nr_dies, cs->nr_cores,
> +                                                   cs->nr_threads);
> +            *ebx = env->nr_dies * cs->nr_cores * cs->nr_threads;
> +            *ecx |= CPUID_TOPOLOGY_LEVEL_DIE;
> +            break;
> +        default:
> +            *eax = 0;
> +            *ebx = 0;
> +            *ecx |= CPUID_TOPOLOGY_LEVEL_INVALID;
> +        }
>          assert(!(*eax & ~0x1f));
>          *ebx &= 0xffff; /* The count doesn't need to be reliable. */
>          break;
> @@ -5890,6 +5926,7 @@ static Property x86_cpu_properties[] = {
>      DEFINE_PROP_BOOL("full-cpuid-auto-level", X86CPU, full_cpuid_auto_level, 
> true),
>      DEFINE_PROP_STRING("hv-vendor-id", X86CPU, hyperv_vendor_id),
>      DEFINE_PROP_BOOL("cpuid-0xb", X86CPU, enable_cpuid_0xb, true),
> +    DEFINE_PROP_BOOL("cpuid-0x1f", X86CPU, enable_cpuid_0x1f, true),
>      DEFINE_PROP_BOOL("lmce", X86CPU, enable_lmce, false),
>      DEFINE_PROP_BOOL("l3-cache", X86CPU, enable_l3_cache, true),
>      DEFINE_PROP_BOOL("kvm-no-smi-migration", X86CPU, kvm_no_smi_migration,
> diff --git a/target/i386/cpu.h b/target/i386/cpu.h
> index 69495f0a8a..0434dfb62a 100644
> --- a/target/i386/cpu.h
> +++ b/target/i386/cpu.h
> @@ -726,6 +726,7 @@ typedef uint32_t FeatureWordArray[FEATURE_WORDS];
>  #define CPUID_TOPOLOGY_LEVEL_INVALID  (0U << 8)
>  #define CPUID_TOPOLOGY_LEVEL_SMT      (1U << 8)
>  #define CPUID_TOPOLOGY_LEVEL_CORE     (2U << 8)
> +#define CPUID_TOPOLOGY_LEVEL_DIE      (5U << 8)
>  
>  /* MSR Feature Bits */
>  #define MSR_ARCH_CAP_RDCL_NO    (1U << 0)
> @@ -1444,6 +1445,9 @@ struct X86CPU {
>      /* Compatibility bits for old machine types: */
>      bool enable_cpuid_0xb;
>  
> +    /* V2 Compatibility bits for old machine types: */
> +    bool enable_cpuid_0x1f;
> +
>      /* Enable auto level-increase for all CPUID leaves */
>      bool full_cpuid_auto_level;
>  
> diff --git a/target/i386/kvm.c b/target/i386/kvm.c
> index 3b29ce5c0d..9b4da9b265 100644
> --- a/target/i386/kvm.c
> +++ b/target/i386/kvm.c
> @@ -1081,6 +1081,10 @@ int kvm_arch_init_vcpu(CPUState *cs)
>              }
>              break;
>          }
> +        case 0x1f:
> +            if (env->nr_dies < 2 || !cpu->enable_cpuid_0x1f) {
> +                break;
> +            }
>          case 4:
>          case 0xb:
>          case 0xd:
> @@ -1088,6 +1092,11 @@ int kvm_arch_init_vcpu(CPUState *cs)
>                  if (i == 0xd && j == 64) {
>                      break;
>                  }
> +
> +                if (i == 0x1f && j == 64) {
> +                    break;
> +                }
> +
>                  c->function = i;
>                  c->flags = KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
>                  c->index = j;
> @@ -1099,6 +1108,9 @@ int kvm_arch_init_vcpu(CPUState *cs)
>                  if (i == 0xb && !(c->ecx & 0xff00)) {
>                      break;
>                  }
> +                if (i == 0x1f && !(c->ecx & 0xff00)) {
> +                    break;
> +                }
>                  if (i == 0xd && c->eax == 0) {
>                      continue;
>                  }
> -- 
> 2.21.0
> 

-- 
Eduardo