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Re: [PATCH v4 17/21] i386: support 'hv-passthrough, hv-feature=off' on t
From: |
Vitaly Kuznetsov |
Subject: |
Re: [PATCH v4 17/21] i386: support 'hv-passthrough, hv-feature=off' on the command line |
Date: |
Fri, 12 Feb 2021 09:49:46 +0100 |
Igor Mammedov <imammedo@redhat.com> writes:
> On Wed, 10 Feb 2021 17:40:29 +0100
> Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
>
>> Currently, we support 'hv-passthrough,hv-feature=on' enablement, this
>> is supposed to mean "hv-feature is mandatory, don't start without it". Add
>> support for 'hv-passthrough,hv-feature=off' meaning "enable everything
>> supported by the host except for hv-feature".
>>
>> While on it, make 'hv-passthrough' parse semantics in-line with other
>> options in qemu: when specified, it overrides what was previously set with
>> what's supported by the host. This can later be modified with
>> 'hv-feature=on'/
>> 'hv-feature=off'.
>>
>> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
>> ---
>> target/i386/cpu.c | 28 +++++++++++++++++++++++++++-
>> target/i386/kvm/kvm.c | 4 ++++
>> 2 files changed, 31 insertions(+), 1 deletion(-)
>>
>> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
>> index e8a004c39d04..f8df2caed779 100644
>> --- a/target/i386/cpu.c
>> +++ b/target/i386/cpu.c
>> @@ -4725,6 +4725,29 @@ static void x86_hv_stimer_direct_set(Object *obj,
>> bool value, Error **errp)
>> x86_hv_feature_set(obj, value, HYPERV_FEAT_STIMER_DIRECT);
>> }
>>
>> +static bool x86_hv_passthrough_get(Object *obj, Error **errp)
>> +{
>> + X86CPU *cpu = X86_CPU(obj);
>> +
>> + return cpu->hyperv_passthrough;
>> +}
>> +
>> +static void x86_hv_passthrough_set(Object *obj, bool value, Error **errp)
>> +{
>> + X86CPU *cpu = X86_CPU(obj);
>> +
>> + cpu->hyperv_passthrough = value;
>> +
>> + /* hv-passthrough overrides everything with what's supported by the
>> host */
>> + if (value) {
>> + cpu->hyperv_features = 0;
>> + cpu->hyperv_features_on = 0;
>> + cpu->hyperv_features_off = 0;
>
> why do we have _on|_off fields?
>
You mean 'why do we have them at all' or 'why do we reset them here'?
For the former, we need to distinguish between
'hv-passthroug,hv-feature=off' and just 'hv-passthrough';
'hv-passthrough,hv-evmcs=on' and just 'hv-passthrough'. For the later,
I'd like to make the samentics you've asked for:
'hv-feature,hv-passthrough' == 'hv-passthrough'
(though I still see it as a gotcha for an unprepared user)
>> + }
>> +
>> + return;
>> +}
>> +
>> /* Generic getter for "feature-words" and "filtered-features" properties */
>> static void x86_cpu_get_feature_words(Object *obj, Visitor *v,
>> const char *name, void *opaque,
>> @@ -7281,7 +7304,6 @@ static Property x86_cpu_properties[] = {
>> HYPERV_SPINLOCK_NEVER_NOTIFY),
>> DEFINE_PROP_ON_OFF_AUTO("hv-no-nonarch-coresharing", X86CPU,
>> hyperv_no_nonarch_cs, ON_OFF_AUTO_OFF),
>> - DEFINE_PROP_BOOL("hv-passthrough", X86CPU, hyperv_passthrough, false),
>>
>> DEFINE_PROP_BOOL("check", X86CPU, check_cpuid, true),
>> DEFINE_PROP_BOOL("enforce", X86CPU, enforce_cpuid, false),
>> @@ -7460,6 +7482,10 @@ static void x86_cpu_common_class_init(ObjectClass
>> *oc, void *data)
>> x86_hv_stimer_direct_get,
>> x86_hv_stimer_direct_set);
>>
>> + object_class_property_add_bool(oc, "hv-passthrough",
>> + x86_hv_passthrough_get,
>> + x86_hv_passthrough_set);
>> +
>> for (w = 0; w < FEATURE_WORDS; w++) {
>> int bitnr;
>> for (bitnr = 0; bitnr < 64; bitnr++) {
>> diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
>> index 30013f0d7cee..fca088d4d3b5 100644
>> --- a/target/i386/kvm/kvm.c
>> +++ b/target/i386/kvm/kvm.c
>> @@ -1153,6 +1153,10 @@ static int hv_cpuid_check_and_set(CPUState *cs, int
>> feature, Error **errp)
>> return 0;
>> }
>>
>> + if (cpu->hyperv_passthrough && (cpu->hyperv_features_off &
>> BIT(feature))) {
>> + return 0;
>> + }
>> +
>> deps = kvm_hyperv_properties[feature].dependencies;
>> while (deps) {
>> dep_feat = ctz64(deps);
>
--
Vitaly
- Re: [PATCH v4 16/21] i386: track explicit 'hv-*' features enablement/disablement, (continued)
- [PATCH v4 15/21] i386: expand Hyper-V features during CPU feature expansion time, Vitaly Kuznetsov, 2021/02/10
- [PATCH v4 14/21] i386: use global kvm_state in hyperv_enabled() check, Vitaly Kuznetsov, 2021/02/10
- [PATCH v4 21/21] qtest/hyperv: Introduce a simple hyper-v test, Vitaly Kuznetsov, 2021/02/10
- [PATCH v4 20/21] i386: provide simple 'hv-default=on' option, Vitaly Kuznetsov, 2021/02/10
- [PATCH v4 17/21] i386: support 'hv-passthrough, hv-feature=off' on the command line, Vitaly Kuznetsov, 2021/02/10
- [PATCH v4 18/21] i386: be more picky about implicit 'hv-evmcs' enablement, Vitaly Kuznetsov, 2021/02/10
- [PATCH v4 19/21] i386: introduce kvm_hv_evmcs_available(), Vitaly Kuznetsov, 2021/02/10
- Re: [PATCH v4 00/19] i386: KVM: expand Hyper-V features early and provide simple 'hv-default=on' option, Daniel P . Berrangé, 2021/02/10