[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [PULL 5/5] i386/kvm: add a comment explaining why .feat_nam
From: |
Eduardo Habkost |
Subject: |
[Qemu-devel] [PULL 5/5] i386/kvm: add a comment explaining why .feat_names are commented out for Hyper-V feature bits |
Date: |
Mon, 14 Jan 2019 12:34:32 -0200 |
From: Vitaly Kuznetsov <address@hidden>
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 <address@hidden>
Message-Id: <address@hidden>
Signed-off-by: Eduardo Habkost <address@hidden>
---
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 = {
--
2.18.0.rc1.1.g3f1ff2140
- [Qemu-devel] [PULL 0/5] x86 queue, 2019-01-14, Eduardo Habkost, 2019/01/14
- [Qemu-devel] [PULL 3/5] target/i386: Disable MPX support on named CPU models, Eduardo Habkost, 2019/01/14
- [Qemu-devel] [PULL 4/5] x86: host-phys-bits-limit option, Eduardo Habkost, 2019/01/14
- [Qemu-devel] [PULL 5/5] i386/kvm: add a comment explaining why .feat_names are commented out for Hyper-V feature bits,
Eduardo Habkost <=
- [Qemu-devel] [PULL 2/5] target-i386: Reenable RDTSCP support on Opteron_G[345] CPU models CPU models, Eduardo Habkost, 2019/01/14
- [Qemu-devel] [PULL 1/5] i386/kvm: expose HV_CPUID_ENLIGHTMENT_INFO.EAX and HV_CPUID_NESTED_FEATURES.EAX as feature words, Eduardo Habkost, 2019/01/14
- Re: [Qemu-devel] [PULL 0/5] x86 queue, 2019-01-14, Peter Maydell, 2019/01/14