From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: Igor Mammedov <imammedo@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
qemu-devel@nongnu.org, Eduardo Habkost <ehabkost@redhat.com>
Subject: Re: [PATCH v4 20/21] i386: provide simple 'hv-default=on' option
Date: Fri, 12 Feb 2021 09:52:05 +0100 [thread overview]
Message-ID: <87o8gpllca.fsf@vitty.brq.redhat.com> (raw)
In-Reply-To: <20210211182337.209986c1@redhat.com>
Igor Mammedov <imammedo@redhat.com> writes:
> On Wed, 10 Feb 2021 17:40:32 +0100
> Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
>
>> Enabling Hyper-V emulation for a Windows VM is a tiring experience as it
>> requires listing all currently supported enlightenments ("hv-*" CPU
>> features) explicitly. We do have 'hv-passthrough' mode enabling
>> everything but it can't be used in production as it prevents migration.
>>
>> Introduce a simple 'hv-default=on' CPU flag enabling all currently supported
>> Hyper-V enlightenments. Later, when new enlightenments get implemented,
>> compat_props mechanism will be used to disable them for legacy machine types,
>> this will keep 'hv-default=on' configurations migratable.
>>
>> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
>> ---
>> docs/hyperv.txt | 16 ++++++++++++---
>> target/i386/cpu.c | 52 +++++++++++++++++++++++++++++++++++++++++++++++
>> target/i386/cpu.h | 3 +++
>> 3 files changed, 68 insertions(+), 3 deletions(-)
>>
>> diff --git a/docs/hyperv.txt b/docs/hyperv.txt
>> index 5df00da54fc4..a54c066cab09 100644
>> --- a/docs/hyperv.txt
>> +++ b/docs/hyperv.txt
>> @@ -17,10 +17,20 @@ compatible hypervisor and use Hyper-V specific features.
>>
>> 2. Setup
>> =========
>> -No Hyper-V enlightenments are enabled by default by either KVM or QEMU. In
>> -QEMU, individual enlightenments can be enabled through CPU flags, e.g:
>> +All currently supported Hyper-V enlightenments can be enabled by specifying
>> +'hv-default=on' CPU flag:
>>
>> - qemu-system-x86_64 --enable-kvm --cpu host,hv_relaxed,hv_vpindex,hv_time, ...
>> + qemu-system-x86_64 --enable-kvm --cpu host,hv-default ...
>> +
>> +Alternatively, it is possible to do fine-grained enablement through CPU flags,
>> +e.g:
>> +
>> + qemu-system-x86_64 --enable-kvm --cpu host,hv-relaxed,hv-vpindex,hv-time ...
>> +
>> +It is also possible to disable individual enlightenments from the default list,
>> +this can be used for debugging purposes:
>> +
>> + qemu-system-x86_64 --enable-kvm --cpu host,hv-default=on,hv-evmcs=off ...
>>
>> Sometimes there are dependencies between enlightenments, QEMU is supposed to
>> check that the supplied configuration is sane.
>> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
>> index f8df2caed779..013aa60272d8 100644
>> --- a/target/i386/cpu.c
>> +++ b/target/i386/cpu.c
>> @@ -4736,6 +4736,12 @@ static void x86_hv_passthrough_set(Object *obj, bool value, Error **errp)
>> {
>> X86CPU *cpu = X86_CPU(obj);
>>
>> + if (cpu->hyperv_default) {
^^^ here ^^^
>> + error_setg(errp,
>> + "'hv-default' and 'hv-paththrough' are mutually exclusive");
>> + return;
>> + }
>> +
>> cpu->hyperv_passthrough = value;
>>
>> /* hv-passthrough overrides everything with what's supported by the host */
>> @@ -4748,6 +4754,33 @@ static void x86_hv_passthrough_set(Object *obj, bool value, Error **errp)
>> return;
>> }
>>
>> +static bool x86_hv_default_get(Object *obj, Error **errp)
>> +{
>> + X86CPU *cpu = X86_CPU(obj);
>> +
>> + return cpu->hyperv_default;
>> +}
>> +
>> +static void x86_hv_default_set(Object *obj, bool value, Error **errp)
>> +{
>> + X86CPU *cpu = X86_CPU(obj);
>> +
>> + if (cpu->hyperv_passthrough) {
>> + error_setg(errp,
>> + "'hv-default' and 'hv-paththrough' are mutually exclusive");
> this check will work only half way, i.e.: hv-paththrough=on,hv-default=on|off
> (where off value looks a bit wierd)
> but not other way around: hv-default=on,hv-paththrough=on
The check in x86_hv_passthrough_set() chechs the opposite scenario.
>
> were you thinking about following error:
> "hv-default can't be used after hv-paththrough were enabled"
>
> or if it symmetric, then putting this check in realizefn() will do the job
> as both properties are processed by that time.
I can move the check there but I think that two checks I add here cover
what we need (and we don't need to care what to set 'hyperv_features' to
in the interim).
>
>> + return;
>> + }
>> +
>> + cpu->hyperv_default = value;
>> +
>> + /* hv-default overrides everything with the default set */
>> + if (value) {
>> + cpu->hyperv_features = cpu->hyperv_default_features;
>> + cpu->hyperv_features_on = 0;
>> + cpu->hyperv_features_off = 0;
>> + }
>> +}
>> +
>> /* 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,
>> @@ -7152,6 +7185,21 @@ static void x86_cpu_initfn(Object *obj)
>> if (xcc->model) {
>> x86_cpu_load_model(cpu, xcc->model);
>> }
>> +
>> + /* Hyper-V features enabled with 'hv-default=on' */
>> + cpu->hyperv_default_features = BIT(HYPERV_FEAT_RELAXED) |
>> + BIT(HYPERV_FEAT_VAPIC) | BIT(HYPERV_FEAT_TIME) |
>> + BIT(HYPERV_FEAT_CRASH) | BIT(HYPERV_FEAT_RESET) |
>> + BIT(HYPERV_FEAT_VPINDEX) | BIT(HYPERV_FEAT_RUNTIME) |
>> + BIT(HYPERV_FEAT_SYNIC) | BIT(HYPERV_FEAT_STIMER) |
>> + BIT(HYPERV_FEAT_FREQUENCIES) | BIT(HYPERV_FEAT_REENLIGHTENMENT) |
>> + BIT(HYPERV_FEAT_TLBFLUSH) | BIT(HYPERV_FEAT_IPI) |
>> + BIT(HYPERV_FEAT_STIMER_DIRECT);
>> +
>> + /* Enlightened VMCS is only available on Intel/VMX */
>> + if (kvm_hv_evmcs_available()) {
>> + cpu->hyperv_default_features |= BIT(HYPERV_FEAT_EVMCS);
>> + }
>> }
>>
>> static int64_t x86_cpu_get_arch_id(CPUState *cs)
>> @@ -7486,6 +7534,10 @@ static void x86_cpu_common_class_init(ObjectClass *oc, void *data)
>> x86_hv_passthrough_get,
>> x86_hv_passthrough_set);
>>
>> + object_class_property_add_bool(oc, "hv-default",
>> + x86_hv_default_get,
>> + x86_hv_default_set);
>> +
>> for (w = 0; w < FEATURE_WORDS; w++) {
>> int bitnr;
>> for (bitnr = 0; bitnr < 64; bitnr++) {
>> diff --git a/target/i386/cpu.h b/target/i386/cpu.h
>> index b4fbd46f0fc9..59350e70fb51 100644
>> --- a/target/i386/cpu.h
>> +++ b/target/i386/cpu.h
>> @@ -1670,6 +1670,9 @@ struct X86CPU {
>> uint64_t hyperv_features_on;
>> uint64_t hyperv_features_off;
>> bool hyperv_passthrough;
>> + /* 'hv-default' enablement */
>> + uint64_t hyperv_default_features;
>> + bool hyperv_default;
>> OnOffAuto hyperv_no_nonarch_cs;
>> uint32_t hyperv_vendor_id[3];
>> uint32_t hyperv_interface_id[4];
>
--
Vitaly
next prev parent reply other threads:[~2021-02-12 8:53 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-10 16:40 [PATCH v4 00/19] i386: KVM: expand Hyper-V features early and provide simple 'hv-default=on' option Vitaly Kuznetsov
2021-02-10 16:40 ` [PATCH v4 01/21] i386: keep hyperv_vendor string up-to-date Vitaly Kuznetsov
2021-02-10 16:40 ` [PATCH v4 02/21] i386: invert hyperv_spinlock_attempts setting logic with hv_passthrough Vitaly Kuznetsov
2021-02-10 16:40 ` [PATCH v4 03/21] i386: always fill Hyper-V CPUID feature leaves from X86CPU data Vitaly Kuznetsov
2021-02-10 16:40 ` [PATCH v4 04/21] i386: stop using env->features[] for filling Hyper-V CPUIDs Vitaly Kuznetsov
2021-02-10 16:40 ` [PATCH v4 05/21] i386: introduce hyperv_feature_supported() Vitaly Kuznetsov
2021-02-10 16:40 ` [PATCH v4 06/21] i386: introduce hv_cpuid_get_host() Vitaly Kuznetsov
2021-02-10 16:40 ` [PATCH v4 07/21] i386: drop FEAT_HYPERV feature leaves Vitaly Kuznetsov
2021-02-10 16:40 ` [PATCH v4 08/21] i386: introduce hv_cpuid_cache Vitaly Kuznetsov
2021-02-10 16:40 ` [PATCH v4 09/21] i386: split hyperv_handle_properties() into hyperv_expand_features()/hyperv_fill_cpuids() Vitaly Kuznetsov
2021-02-10 16:40 ` [PATCH v4 10/21] i386: move eVMCS enablement to hyperv_init_vcpu() Vitaly Kuznetsov
2021-02-10 16:40 ` [PATCH v4 11/21] i386: switch hyperv_expand_features() to using error_setg() Vitaly Kuznetsov
2021-02-10 16:40 ` [PATCH v4 12/21] i386: adjust the expected KVM_GET_SUPPORTED_HV_CPUID array size Vitaly Kuznetsov
2021-02-10 16:40 ` [PATCH v4 13/21] i386: prefer system KVM_GET_SUPPORTED_HV_CPUID ioctl over vCPU's one Vitaly Kuznetsov
2021-02-10 16:40 ` [PATCH v4 14/21] i386: use global kvm_state in hyperv_enabled() check Vitaly Kuznetsov
2021-02-10 16:40 ` [PATCH v4 15/21] i386: expand Hyper-V features during CPU feature expansion time Vitaly Kuznetsov
2021-02-10 16:40 ` [PATCH v4 16/21] i386: track explicit 'hv-*' features enablement/disablement Vitaly Kuznetsov
2021-02-11 17:35 ` Igor Mammedov
2021-02-12 8:45 ` Vitaly Kuznetsov
2021-02-12 14:12 ` Igor Mammedov
2021-02-12 15:19 ` Vitaly Kuznetsov
2021-02-12 15:26 ` Vitaly Kuznetsov
2021-02-12 16:05 ` Igor Mammedov
2021-02-15 8:56 ` Vitaly Kuznetsov
2021-02-15 15:55 ` Igor Mammedov
2021-02-15 17:05 ` Igor Mammedov
2021-02-15 18:12 ` Vitaly Kuznetsov
2021-02-12 16:01 ` Igor Mammedov
2021-02-15 8:53 ` Vitaly Kuznetsov
2021-02-15 10:48 ` Andrew Jones
2021-02-15 17:01 ` Igor Mammedov
2021-02-15 18:11 ` Vitaly Kuznetsov
2021-02-22 10:20 ` Vitaly Kuznetsov
2021-02-23 15:19 ` Igor Mammedov
2021-02-23 15:46 ` Vitaly Kuznetsov
2021-02-23 17:48 ` Igor Mammedov
2021-02-23 18:08 ` Vitaly Kuznetsov
2021-02-24 16:06 ` Igor Mammedov
2021-02-24 17:00 ` Vitaly Kuznetsov
2021-03-01 15:32 ` Igor Mammedov
2021-03-01 16:22 ` Vitaly Kuznetsov
2021-02-10 16:40 ` [PATCH v4 17/21] i386: support 'hv-passthrough, hv-feature=off' on the command line Vitaly Kuznetsov
2021-02-11 17:14 ` Igor Mammedov
2021-02-12 8:49 ` Vitaly Kuznetsov
2021-02-12 9:29 ` David Edmondson
2021-02-12 13:52 ` Igor Mammedov
2021-02-10 16:40 ` [PATCH v4 18/21] i386: be more picky about implicit 'hv-evmcs' enablement Vitaly Kuznetsov
2021-02-10 16:40 ` [PATCH v4 19/21] i386: introduce kvm_hv_evmcs_available() Vitaly Kuznetsov
2021-02-10 16:40 ` [PATCH v4 20/21] i386: provide simple 'hv-default=on' option Vitaly Kuznetsov
2021-02-11 17:23 ` Igor Mammedov
2021-02-12 8:52 ` Vitaly Kuznetsov [this message]
2021-02-10 16:40 ` [PATCH v4 21/21] qtest/hyperv: Introduce a simple hyper-v test Vitaly Kuznetsov
2021-02-10 16:56 ` [PATCH v4 00/19] i386: KVM: expand Hyper-V features early and provide simple 'hv-default=on' option Daniel P. Berrangé
2021-02-10 17:46 ` Eduardo Habkost
2021-02-11 8:30 ` Vitaly Kuznetsov
2021-02-11 9:14 ` Daniel P. Berrangé
2021-02-11 9:34 ` Vitaly Kuznetsov
2021-02-11 10:14 ` Daniel P. Berrangé
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