Commit 0d914f39 authored by Eduardo Habkost's avatar Eduardo Habkost
Browse files

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: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarEduardo Habkost <ehabkost@redhat.com>
Message-Id: <20180410211534.26079-1-ehabkost@redhat.com>
Tested-by: default avatarWanpeng Li <wanpengli@tencent.com>
Signed-off-by: default avatarEduardo Habkost <ehabkost@redhat.com>
parent 042f6a31

target/i386/cpu.c

+9 −1
Original line number Diff line number Diff line
@@ -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;

        }

    }