[v13,5/5] i386: Remove generic SMT thread check

Commit Message

Babu Moger June 8, 2018, 10:56 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 <[e-mail]>
Tested-by: Geoffrey McRae <[e-mail]>
Reviewed-by: Eduardo Habkost <[e-mail]>
---
 target/i386/cpu.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

Patch

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 88bc73d..a55e501 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -4993,17 +4993,22 @@  static void x86_cpu_realizefn(DeviceState *dev, Error **errp)
         return;
     }
 
-    /* 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(%d). Please configure -smp "
+                         "options properly or try enabling topoext feature.",
+                         cs->nr_threads);
         ht_warned = true;
     }