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authorVitaly Kuznetsov <vkuznets@redhat.com>2018-12-21 15:16:04 +0100
committerEduardo Habkost <ehabkost@redhat.com>2019-01-14 12:28:44 -0200
commitabd5fc4c862d033a989552914149f01c9476bb16 (patch)
treeea941b6b2a3ceff404d1a95261b5f312013801e6
parent258fe08bd341d2e230676228307294e41f33002c (diff)
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>
-rw-r--r--target/i386/cpu.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 3ece83696e..2f5412592d 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -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 = {