From b6cc2c4e06cdf57b7d45dcab0df8390a7b53f9e3 Mon Sep 17 00:00:00 2001
From: Vitaly Kuznetsov <vkuznets@redhat.com>
Date: Mon, 14 Jan 2019 15:02:33 -0500
Subject: [PATCH] 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.
Backports commit abd5fc4c862d033a989552914149f01c9476bb16 from qemu
---
qemu/target/i386/cpu.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/qemu/target/i386/cpu.c b/qemu/target/i386/cpu.c
index 6ad79729..effe703f 100644
--- a/qemu/target/i386/cpu.c
+++ b/qemu/target/i386/cpu.c
@@ -1025,6 +1025,13 @@ 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,