i386/kvm: add a comment explaining why .feat_names are commented out for Hyper-V feature bits

Hyper-V .feat_names are, unlike hardware features, commented out and it is
not obvious why we do that. Document the current status quo.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20181221141604.16935-1-vkuznets@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
This commit is contained in:
Vitaly Kuznetsov 2018-12-21 15:16:04 +01:00 committed by Eduardo Habkost
parent 258fe08bd3
commit abd5fc4c86
1 changed files with 7 additions and 0 deletions

View File

@ -929,6 +929,13 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
*/
.no_autoenable_flags = ~0U,
},
/*
* .feat_names are commented out for Hyper-V enlightenments because we
* don't want to have two different ways for enabling them on QEMU command
* line. Some features (e.g. "hyperv_time", "hyperv_vapic", ...) require
* enabling several feature bits simultaneously, exposing these bits
* individually may just confuse guests.
*/
[FEAT_HYPERV_EAX] = {
.type = CPUID_FEATURE_WORD,
.feat_names = {