From abd5fc4c862d033a989552914149f01c9476bb16 Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Fri, 21 Dec 2018 15:16:04 +0100 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. Signed-off-by: Vitaly Kuznetsov Message-Id: <20181221141604.16935-1-vkuznets@redhat.com> Signed-off-by: Eduardo Habkost --- target/i386/cpu.c | 7 +++++++ 1 file changed, 7 insertions(+) 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 = {