[RFC,v2,09/12] target/i386: allow versioned CPUs to specify new cache_info

Commit Message

Michael Roth Aug. 26, 2021, 10:26 p.m. UTC

New EPYC CPUs versions require small changes to their cache_info's.
Because current QEMU x86 CPU definition does not support cache
versions, we would have to declare a new CPU type for each such case.
To avoid this duplication, the patch allows new cache_info pointers to
be specificed for a new CPU version.

Co-developed-by: Wei Huang <[e-mail]>
Signed-off-by: Wei Huang <[e-mail]>
Signed-off-by: Michael Roth <[e-mail]>
---
 target/i386/cpu.c | 36 +++++++++++++++++++++++++++++++++---
 1 file changed, 33 insertions(+), 3 deletions(-)

Patch

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index f0b441f692..85d387163a 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -1458,6 +1458,7 @@  typedef struct X86CPUVersionDefinition {
     const char *alias;
     const char *note;
     PropValue *props;
+    const CPUCaches *const cache_info;
 } X86CPUVersionDefinition;
 
 /* Base definition for a CPU model */
@@ -4975,6 +4976,32 @@  static void x86_cpu_apply_version_props(X86CPU *cpu, X86CPUModel *model)
     assert(vdef->version == version);
 }
 
+/* Apply properties for the CPU model version specified in model */
+static const CPUCaches *x86_cpu_get_version_cache_info(X86CPU *cpu,
+                                                       X86CPUModel *model)
+{
+    const X86CPUVersionDefinition *vdef;
+    X86CPUVersion version = x86_cpu_model_resolve_version(model);
+    const CPUCaches *cache_info = model->cpudef->cache_info;
+
+    if (version == CPU_VERSION_LEGACY) {
+        return cache_info;
+    }
+
+    for (vdef = x86_cpu_def_get_versions(model->cpudef); vdef->version; vdef++) {
+        if (vdef->cache_info) {
+            cache_info = vdef->cache_info;
+        }
+
+        if (vdef->version == version) {
+            break;
+        }
+    }
+
+    assert(vdef->version == version);
+    return cache_info;
+}
+
 /*
  * Load data from X86CPUDefinition into a X86CPU object.
  * Only for builtin_x86_defs models initialized with x86_register_cpudef_types.
@@ -5007,7 +5034,7 @@  static void x86_cpu_load_model(X86CPU *cpu, X86CPUModel *model)
     }
 
     /* legacy-cache defaults to 'off' if CPU model provides cache info */
-    cpu->legacy_cache = !def->cache_info;
+    cpu->legacy_cache = !x86_cpu_get_version_cache_info(cpu, model);
 
     env->features[FEAT_1_ECX] |= CPUID_EXT_HYPERVISOR;
 
@@ -6234,14 +6261,17 @@  static void x86_cpu_realizefn(DeviceState *dev, Error **errp)
 
     /* Cache information initialization */
     if (!cpu->legacy_cache) {
-        if (!xcc->model || !xcc->model->cpudef->cache_info) {
+        const CPUCaches *cache_info =
+            x86_cpu_get_version_cache_info(cpu, xcc->model);
+
+        if (!xcc->model || !cache_info) {
             g_autofree char *name = x86_cpu_class_get_model_name(xcc);
             error_setg(errp,
                        "CPU model '%s' doesn't support legacy-cache=off", name);
             return;
         }
         env->cache_info_cpuid2 = env->cache_info_cpuid4 = env->cache_info_amd =
-            *xcc->model->cpudef->cache_info;
+            *cache_info;
     } else {
         /* Build legacy cache information */
         env->cache_info_cpuid2.l1d_cache = &legacy_l1d_cache;