diff mbox

[v8,8/8] i386: Remove generic SMT thread check

Message ID 20180510204148.11687-9-babu.moger@amd.com (mailing list archive)
State New, archived
Headers show

Commit Message

Babu Moger May 10, 2018, 8:41 p.m. UTC 
Remove generic non-intel check while validating hyperthreading support.
Certain AMD CPUs can support hyperthreading now.

CPU family with TOPOEXT feature can support hyperthreading now.

Signed-off-by: Babu Moger <babu.moger@amd.com>
Tested-by: Geoffrey McRae <geoff@hostfission.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
---
 target/i386/cpu.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)
diff mbox

Patch

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 575f2416a1..17803135ed 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -4790,17 +4790,20 @@  static void x86_cpu_realizefn(DeviceState *dev, Error **errp)
 
     qemu_init_vcpu(cs);
 
-    /* Only Intel CPUs support hyperthreading. Even though QEMU 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 gives
+    /* Most Intel and certain AMD CPUs support hyperthreading. Even though QEMU
+     * 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_INTEL_CPU(env) && cs->nr_threads > 1 && !ht_warned) {
-        error_report("AMD CPU doesn't support hyperthreading. Please configure"
-                     " -smp options properly.");
+     if (IS_AMD_CPU(env) &&
+         !(env->features[FEAT_8000_0001_ECX] & CPUID_EXT3_TOPOEXT) &&
+         cs->nr_threads > 1 && !ht_warned) {
+            error_report("This family of AMD CPU doesn't support "
+                         "hyperthreading. Please configure -smp "
+                         "options properly.");
         ht_warned = true;
     }