qemu-kvm/kvm-i386-cpu-Track-a-X86CPUTopoInfo-directly-in-CPUX86St.patch

From 03d6e64ed980335602368d3b470e33cb21af307d Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Fri, 18 Jul 2025 18:03:44 +0200
Subject: [PATCH 012/115] i386/cpu: Track a X86CPUTopoInfo directly in
 CPUX86State

RH-Author: Paolo Bonzini <pbonzini@redhat.com>
RH-MergeRequest: 391: TDX support, including attestation and device assignment
RH-Jira: RHEL-15710 RHEL-20798 RHEL-49728
RH-Acked-by: Yash Mankad <None>
RH-Acked-by: Peter Xu <peterx@redhat.com>
RH-Acked-by: David Hildenbrand <david@redhat.com>
RH-Commit: [12/115] 4d23b4e386ec4179739869c1ace2bb2b9f728bde (bonzini/rhel-qemu-kvm)

The name of nr_modules/nr_dies are ambiguous and they mislead people.

The purpose of them is to record and form the topology information. So
just maintain a X86CPUTopoInfo member in CPUX86State instead. Then
nr_modules and nr_dies can be dropped.

As the benefit, x86 can switch to use information in
CPUX86State::topo_info and get rid of the nr_cores and nr_threads in
CPUState. This helps remove the dependency on qemu_init_vcpu(), so that
x86 can get and use topology info earlier in x86_cpu_realizefn(); drop
the comment that highlighted the depedency.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Link: https://lore.kernel.org/r/20241219110125.1266461-7-xiaoyao.li@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 84b71a131c1bc84c36fafb63271080ecf9f2ff7a)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit f598befcd2cddbf01f7606102400cec4acd35d48)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/i386/x86-common.c     | 12 ++++------
 target/i386/cpu-sysemu.c |  6 ++---
 target/i386/cpu.c        | 51 +++++++++++++++++-----------------------
 target/i386/cpu.h        |  6 +----
 4 files changed, 30 insertions(+), 45 deletions(-)

diff --git a/hw/i386/x86-common.c b/hw/i386/x86-common.c
index 2806be98f3..562215990d 100644
--- a/hw/i386/x86-common.c
+++ b/hw/i386/x86-common.c
@@ -248,7 +248,7 @@ void x86_cpu_pre_plug(HotplugHandler *hotplug_dev,
     CPUX86State *env = &cpu->env;
     MachineState *ms = MACHINE(hotplug_dev);
     X86MachineState *x86ms = X86_MACHINE(hotplug_dev);
-    X86CPUTopoInfo topo_info;
+    X86CPUTopoInfo *topo_info = &env->topo_info;
 
     if (!object_dynamic_cast(OBJECT(cpu), ms->cpu_type)) {
         error_setg(errp, "Invalid CPU type, expected cpu type: '%s'",
@@ -267,15 +267,13 @@ void x86_cpu_pre_plug(HotplugHandler *hotplug_dev,
         }
     }
 
-    init_topo_info(&topo_info, x86ms);
+    init_topo_info(topo_info, x86ms);
 
     if (ms->smp.modules > 1) {
-        env->nr_modules = ms->smp.modules;
         set_bit(CPU_TOPO_LEVEL_MODULE, env->avail_cpu_topo);
     }
 
     if (ms->smp.dies > 1) {
-        env->nr_dies = ms->smp.dies;
         set_bit(CPU_TOPO_LEVEL_DIE, env->avail_cpu_topo);
     }
 
@@ -346,12 +344,12 @@ void x86_cpu_pre_plug(HotplugHandler *hotplug_dev,
         topo_ids.module_id = cpu->module_id;
         topo_ids.core_id = cpu->core_id;
         topo_ids.smt_id = cpu->thread_id;
-        cpu->apic_id = x86_apicid_from_topo_ids(&topo_info, &topo_ids);
+        cpu->apic_id = x86_apicid_from_topo_ids(topo_info, &topo_ids);
     }
 
     cpu_slot = x86_find_cpu_slot(MACHINE(x86ms), cpu->apic_id, &idx);
     if (!cpu_slot) {
-        x86_topo_ids_from_apicid(cpu->apic_id, &topo_info, &topo_ids);
+        x86_topo_ids_from_apicid(cpu->apic_id, topo_info, &topo_ids);
 
         error_setg(errp,
             "Invalid CPU [socket: %u, die: %u, module: %u, core: %u, thread: %u]"
@@ -374,7 +372,7 @@ void x86_cpu_pre_plug(HotplugHandler *hotplug_dev,
     /* TODO: move socket_id/core_id/thread_id checks into x86_cpu_realizefn()
      * once -smp refactoring is complete and there will be CPU private
      * CPUState::nr_cores and CPUState::nr_threads fields instead of globals */
-    x86_topo_ids_from_apicid(cpu->apic_id, &topo_info, &topo_ids);
+    x86_topo_ids_from_apicid(cpu->apic_id, topo_info, &topo_ids);
     if (cpu->socket_id != -1 && cpu->socket_id != topo_ids.pkg_id) {
         error_setg(errp, "property socket-id: %u doesn't match set apic-id:"
             " 0x%x (socket-id: %u)", cpu->socket_id, cpu->apic_id,
diff --git a/target/i386/cpu-sysemu.c b/target/i386/cpu-sysemu.c
index 4e9df0bc01..31b37c6325 100644
--- a/target/i386/cpu-sysemu.c
+++ b/target/i386/cpu-sysemu.c
@@ -312,11 +312,11 @@ void x86_cpu_get_crash_info_qom(Object *obj, Visitor *v,
 
 uint64_t cpu_x86_get_msr_core_thread_count(X86CPU *cpu)
 {
-    CPUState *cs = CPU(cpu);
+    CPUX86State *env = &cpu->env;
     uint64_t val;
 
-    val = cs->nr_threads * cs->nr_cores;  /* thread count, bits 15..0 */
-    val |= ((uint32_t)cs->nr_cores << 16); /* core count, bits 31..16 */
+    val = x86_threads_per_pkg(&env->topo_info);  /* thread count, bits 15..0 */
+    val |= x86_cores_per_pkg(&env->topo_info) << 16; /* core count, bits 31..16 */
 
     return val;
 }
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 1c79eb9a06..554455169a 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -6947,15 +6947,10 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
     CPUState *cs = env_cpu(env);
     uint32_t limit;
     uint32_t signature[3];
-    X86CPUTopoInfo topo_info;
+    X86CPUTopoInfo *topo_info = &env->topo_info;
     uint32_t threads_per_pkg;
 
-    topo_info.dies_per_pkg = env->nr_dies;
-    topo_info.modules_per_die = env->nr_modules;
-    topo_info.cores_per_module = cs->nr_cores / env->nr_dies / env->nr_modules;
-    topo_info.threads_per_core = cs->nr_threads;
-
-    threads_per_pkg = x86_threads_per_pkg(&topo_info);
+    threads_per_pkg = x86_threads_per_pkg(topo_info);
 
     /* Calculate & apply limits for different index ranges */
     if (index >= 0xC0000000) {
@@ -7032,12 +7027,12 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
                 int host_vcpus_per_cache = 1 + ((*eax & 0x3FFC000) >> 14);
 
                 *eax &= ~0xFC000000;
-                *eax |= max_core_ids_in_package(&topo_info) << 26;
+                *eax |= max_core_ids_in_package(topo_info) << 26;
                 if (host_vcpus_per_cache > threads_per_pkg) {
                     *eax &= ~0x3FFC000;
 
                     /* Share the cache at package level. */
-                    *eax |= max_thread_ids_for_cache(&topo_info,
+                    *eax |= max_thread_ids_for_cache(topo_info,
                                 CPU_TOPO_LEVEL_PACKAGE) << 14;
                 }
             }
@@ -7049,7 +7044,7 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
             switch (count) {
             case 0: /* L1 dcache info */
                 encode_cache_cpuid4(env->cache_info_cpuid4.l1d_cache,
-                                    &topo_info,
+                                    topo_info,
                                     eax, ebx, ecx, edx);
                 if (!cpu->l1_cache_per_core) {
                     *eax &= ~MAKE_64BIT_MASK(14, 12);
@@ -7057,7 +7052,7 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
                 break;
             case 1: /* L1 icache info */
                 encode_cache_cpuid4(env->cache_info_cpuid4.l1i_cache,
-                                    &topo_info,
+                                    topo_info,
                                     eax, ebx, ecx, edx);
                 if (!cpu->l1_cache_per_core) {
                     *eax &= ~MAKE_64BIT_MASK(14, 12);
@@ -7065,13 +7060,13 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
                 break;
             case 2: /* L2 cache info */
                 encode_cache_cpuid4(env->cache_info_cpuid4.l2_cache,
-                                    &topo_info,
+                                    topo_info,
                                     eax, ebx, ecx, edx);
                 break;
             case 3: /* L3 cache info */
                 if (cpu->enable_l3_cache) {
                     encode_cache_cpuid4(env->cache_info_cpuid4.l3_cache,
-                                        &topo_info,
+                                        topo_info,
                                         eax, ebx, ecx, edx);
                     break;
                 }
@@ -7154,12 +7149,12 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
 
         switch (count) {
         case 0:
-            *eax = apicid_core_offset(&topo_info);
-            *ebx = topo_info.threads_per_core;
+            *eax = apicid_core_offset(topo_info);
+            *ebx = topo_info->threads_per_core;
             *ecx |= CPUID_B_ECX_TOPO_LEVEL_SMT << 8;
             break;
         case 1:
-            *eax = apicid_pkg_offset(&topo_info);
+            *eax = apicid_pkg_offset(topo_info);
             *ebx = threads_per_pkg;
             *ecx |= CPUID_B_ECX_TOPO_LEVEL_CORE << 8;
             break;
@@ -7185,7 +7180,7 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
             break;
         }
 
-        encode_topo_cpuid1f(env, count, &topo_info, eax, ebx, ecx, edx);
+        encode_topo_cpuid1f(env, count, topo_info, eax, ebx, ecx, edx);
         break;
     case 0xD: {
         /* Processor Extended State */
@@ -7488,7 +7483,7 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
              * thread ID within a package".
              * Bits 7:0 is "The number of threads in the package is NC+1"
              */
-            *ecx = (apicid_pkg_offset(&topo_info) << 12) |
+            *ecx = (apicid_pkg_offset(topo_info) << 12) |
                    (threads_per_pkg - 1);
         } else {
             *ecx = 0;
@@ -7517,19 +7512,19 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
         switch (count) {
         case 0: /* L1 dcache info */
             encode_cache_cpuid8000001d(env->cache_info_amd.l1d_cache,
-                                       &topo_info, eax, ebx, ecx, edx);
+                                       topo_info, eax, ebx, ecx, edx);
             break;
         case 1: /* L1 icache info */
             encode_cache_cpuid8000001d(env->cache_info_amd.l1i_cache,
-                                       &topo_info, eax, ebx, ecx, edx);
+                                       topo_info, eax, ebx, ecx, edx);
             break;
         case 2: /* L2 cache info */
             encode_cache_cpuid8000001d(env->cache_info_amd.l2_cache,
-                                       &topo_info, eax, ebx, ecx, edx);
+                                       topo_info, eax, ebx, ecx, edx);
             break;
         case 3: /* L3 cache info */
             encode_cache_cpuid8000001d(env->cache_info_amd.l3_cache,
-                                       &topo_info, eax, ebx, ecx, edx);
+                                       topo_info, eax, ebx, ecx, edx);
             break;
         default: /* end of info */
             *eax = *ebx = *ecx = *edx = 0;
@@ -7541,7 +7536,7 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
         break;
     case 0x8000001E:
         if (cpu->core_id <= 255) {
-            encode_topo_cpuid8000001e(cpu, &topo_info, eax, ebx, ecx, edx);
+            encode_topo_cpuid8000001e(cpu, topo_info, eax, ebx, ecx, edx);
         } else {
             *eax = 0;
             *ebx = 0;
@@ -8440,17 +8435,14 @@ static void x86_cpu_realizefn(DeviceState *dev, Error **errp)
      * fixes this issue by adjusting CPUID_0000_0001_EBX and CPUID_8000_0008_ECX
      * based on inputs (sockets,cores,threads), it is still better to give
      * users a warning.
-     *
-     * NOTE: the following code has to follow qemu_init_vcpu(). Otherwise
-     * cs->nr_threads hasn't be populated yet and the checking is incorrect.
      */
     if (IS_AMD_CPU(env) &&
         !(env->features[FEAT_8000_0001_ECX] & CPUID_EXT3_TOPOEXT) &&
-        cs->nr_threads > 1) {
+        env->topo_info.threads_per_core > 1) {
             warn_report_once("This family of AMD CPU doesn't support "
                              "hyperthreading(%d). Please configure -smp "
                              "options properly or try enabling topoext "
-                             "feature.", cs->nr_threads);
+                             "feature.", env->topo_info.threads_per_core);
     }
 
 #ifndef CONFIG_USER_ONLY
@@ -8611,8 +8603,7 @@ static void x86_cpu_init_default_topo(X86CPU *cpu)
 {
     CPUX86State *env = &cpu->env;
 
-    env->nr_modules = 1;
-    env->nr_dies = 1;
+    env->topo_info = (X86CPUTopoInfo) {1, 1, 1, 1};
 
     /* SMT, core and package levels are set by default. */
     set_bit(CPU_TOPO_LEVEL_SMT, env->avail_cpu_topo);
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index 8c9216d9d0..cc42a2c520 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -2024,11 +2024,7 @@ typedef struct CPUArchState {
 
     TPRAccess tpr_access_type;
 
-    /* Number of dies within this CPU package. */
-    unsigned nr_dies;
-
-    /* Number of modules within one die. */
-    unsigned nr_modules;
+    X86CPUTopoInfo topo_info;
 
     /* Bitmap of available CPU topology levels for this CPU. */
     DECLARE_BITMAP(avail_cpu_topo, CPU_TOPO_LEVEL_MAX);
-- 
2.50.1