[Qemu-devel] [PATCH v13 3/5] i386: Enable TOPOEXT feature on AMD EPYC CPU

[Babu Moger]

Enable TOPOEXT feature on EPYC CPU. This is required to support
hyperthreading on VM guests. Also extend xlevel to 0x8000001E.

TOPOEXT feature is disabled for legacy machines.

Signed-off-by: Babu Moger <address@hidden>
---
 target/i386/cpu.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index d3411ed..4dd9a82 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -2574,6 +2574,7 @@ static X86CPUDefinition builtin_x86_defs[] = {
         .xlevel = 0x8000000A,
         .model_id = "AMD EPYC Processor",
         .cache_info = &epyc_cache_info,
+        .auto_topoext = 1,
     },
     {
         .name = "EPYC-IBPB",
@@ -2621,6 +2622,7 @@ static X86CPUDefinition builtin_x86_defs[] = {
         .xlevel = 0x8000000A,
         .model_id = "AMD EPYC Processor (with IBPB)",
         .cache_info = &epyc_cache_info,
+        .auto_topoext = 1,
     },
 };
 
@@ -4672,6 +4674,11 @@ static void x86_cpu_expand_features(X86CPU *cpu, Error 
**errp)
             x86_cpu_adjust_level(cpu, &env->cpuid_min_xlevel, 0x8000000A);
         }
 
+        /* TOPOEXT feature requires 0x8000001E */
+        if (env->features[FEAT_8000_0001_ECX] & CPUID_EXT3_TOPOEXT) {
+            x86_cpu_adjust_level(cpu, &env->cpuid_min_xlevel, 0x8000001E);
+        }
+
         /* SEV requires CPUID[0x8000001F] */
         if (sev_enabled()) {
             x86_cpu_adjust_level(cpu, &env->cpuid_min_xlevel, 0x8000001F);
-- 
1.8.3.1