i386: Don't automatically enable FEAT_KVM_HINTS bits

The assumption in the cpu->max_features code is that anything enabled on GET_SUPPORTED_CPUID should be enabled on "-cpu host". This shouldn't be the case for FEAT_KVM_HINTS.

This adds a new FeatureWordInfo::no_autoenable_flags field, that can be used to prevent FEAT_KVM_HINTS bits to be enabled automatically.

Reviewed-by Paolo Bonzini <[email protected]>

Signed-off-by Eduardo Habkost <[email protected]>

---
 target/i386/cpu.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

target/i386/cpu.c +9 -2

index 1a6b082b6f..a20fe26573 100644
@@ -295,6 +295,8 @@ typedef struct FeatureWordInfo {
     uint32_t tcg_features; /* Feature flags supported by TCG */
     uint32_t unmigratable_flags; /* Feature flags known to be unmigratable */
     uint32_t migratable_flags; /* Feature flags known to be migratable */
+    /* Features that shouldn't be auto-enabled by "-cpu host" */
+    uint32_t no_autoenable_flags;
 } FeatureWordInfo;
 
 static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {

@@ -400,6 +402,11 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
         },
         .cpuid_eax = KVM_CPUID_FEATURES, .cpuid_reg = R_EDX,
         .tcg_features = TCG_KVM_FEATURES,
+        /*
+         * KVM hints aren't auto-enabled by -cpu host, they need to be
+         * explicitly enabled in the command-line.
+         */
+        .no_autoenable_flags = ~0U,
     },
     [FEAT_HYPERV_EAX] = {
         .feat_names = {

@@ -4062,7 +4069,8 @@ static void x86_cpu_expand_features(X86CPU *cpu, Error **errp)
              */
             env->features[w] |=
                 x86_cpu_get_supported_feature_word(w, cpu->migratable) &
-                ~env->user_features[w];
+                ~env->user_features[w] & \
+                ~feature_word_info[w].no_autoenable_flags;
         }
     }
 
--

2.14.3