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

[Like Xu <like.xu@linux.intel.com>]

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 <like.xu@linux.intel.com>
---
 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