Commit 128531d9 authored by Vitaly Kuznetsov's avatar Vitaly Kuznetsov Committed by Paolo Bonzini
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i386/kvm: add support for Direct Mode for Hyper-V synthetic timers 



Hyper-V on KVM can only use Synthetic timers with Direct Mode (opting for
an interrupt instead of VMBus message). This new capability is only
announced in KVM_GET_SUPPORTED_HV_CPUID.

Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20190517141924.19024-10-vkuznets@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 8caba36d

docs/hyperv.txt

+10 −0
Original line number Diff line number Diff line
@@ -174,6 +174,16 @@ without the feature to find out if enabling it is beneficial. 


Requires: hv-vapic



3.17. hv-stimer-direct

=======================

Hyper-V specification allows synthetic timer operation in two modes: "classic",

when expiration event is delivered as SynIC message and "direct", when the event

is delivered via normal interrupt. It is known that nested Hyper-V can only

use synthetic timers in direct mode and thus 'hv-stimer-direct' needs to be

enabled.



Requires: hv-vpindex, hv-synic, hv-time, hv-stimer





4. Development features

========================

target/i386/cpu.c

+2 −0
Original line number Diff line number Diff line
@@ -5883,6 +5883,8 @@ static Property x86_cpu_properties[] = { 
                      HYPERV_FEAT_EVMCS, 0),

    DEFINE_PROP_BIT64("hv-ipi", X86CPU, hyperv_features,

                      HYPERV_FEAT_IPI, 0),

    DEFINE_PROP_BIT64("hv-stimer-direct", X86CPU, hyperv_features,

                      HYPERV_FEAT_STIMER_DIRECT, 0),

    DEFINE_PROP_BOOL("hv-passthrough", X86CPU, hyperv_passthrough, false),



    DEFINE_PROP_BOOL("check", X86CPU, check_cpuid, true),

target/i386/cpu.h

+1 −0
Original line number Diff line number Diff line
@@ -749,6 +749,7 @@ typedef uint32_t FeatureWordArray[FEATURE_WORDS]; 
#define HYPERV_FEAT_TLBFLUSH            11

#define HYPERV_FEAT_EVMCS               12

#define HYPERV_FEAT_IPI                 13

#define HYPERV_FEAT_STIMER_DIRECT       14



#ifndef HYPERV_SPINLOCK_NEVER_RETRY

#define HYPERV_SPINLOCK_NEVER_RETRY             0xFFFFFFFF

target/i386/hyperv-proto.h

+1 −0
Original line number Diff line number Diff line
@@ -49,6 +49,7 @@ 
#define HV_GUEST_IDLE_STATE_AVAILABLE           (1u << 5)

#define HV_FREQUENCY_MSRS_AVAILABLE             (1u << 8)

#define HV_GUEST_CRASH_MSR_AVAILABLE            (1u << 10)

#define HV_STIMER_DIRECT_MODE_AVAILABLE         (1u << 19)



/*

 * HV_CPUID_ENLIGHTMENT_INFO.EAX bits

target/i386/kvm.c

+9 −0
Original line number Diff line number Diff line
@@ -802,6 +802,14 @@ static struct { 
        },

        .dependencies = BIT(HYPERV_FEAT_VPINDEX)

    },

    [HYPERV_FEAT_STIMER_DIRECT] = {

        .desc = "direct mode synthetic timers (hv-stimer-direct)",

        .flags = {

            {.fw = FEAT_HYPERV_EDX,

             .bits = HV_STIMER_DIRECT_MODE_AVAILABLE}

        },

        .dependencies = BIT(HYPERV_FEAT_STIMER)

    },

};



static struct kvm_cpuid2 *try_get_hv_cpuid(CPUState *cs, int max)
@@ -1124,6 +1132,7 @@ static int hyperv_handle_properties(CPUState *cs, 
    r |= hv_cpuid_check_and_set(cs, cpuid, HYPERV_FEAT_TLBFLUSH);

    r |= hv_cpuid_check_and_set(cs, cpuid, HYPERV_FEAT_EVMCS);

    r |= hv_cpuid_check_and_set(cs, cpuid, HYPERV_FEAT_IPI);

    r |= hv_cpuid_check_and_set(cs, cpuid, HYPERV_FEAT_STIMER_DIRECT);



    /* Additional dependencies not covered by kvm_hyperv_properties[] */

    if (hyperv_feat_enabled(cpu, HYPERV_FEAT_SYNIC) &&