2018-04-11 5:15 GMT+08:00 Eduardo Habkost :
> 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
> Signed-off-by: Eduardo Habkost
Thanks for the patch, Eduardo!
Tested-by: Wanpeng Li
Regards,
Wanpeng Li
> ---
> target/i386/cpu.c | 10 +-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index 1a6b082b6f..a20fe26573 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -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
>