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    Subject[PATCH 07/12] KVM: x86: Move TSC scaling logic out of call-back read_l1_tsc()
    Date
    Both VMX and SVM scales the host TSC in the same way in call-back
    read_l1_tsc(), so this patch moves the scaling logic from call-back
    read_l1_tsc() to a common function kvm_read_l1_tsc().

    Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
    ---
    arch/x86/kvm/lapic.c | 5 ++---
    arch/x86/kvm/svm.c | 3 +--
    arch/x86/kvm/x86.c | 11 ++++++++---
    include/linux/kvm_host.h | 2 ++
    4 files changed, 13 insertions(+), 8 deletions(-)

    diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
    index 8d9013c..b3bb4c9 100644
    --- a/arch/x86/kvm/lapic.c
    +++ b/arch/x86/kvm/lapic.c
    @@ -1,4 +1,3 @@
    -
    /*
    * Local APIC virtualization
    *
    @@ -1172,7 +1171,7 @@ void wait_lapic_expire(struct kvm_vcpu *vcpu)

    tsc_deadline = apic->lapic_timer.expired_tscdeadline;
    apic->lapic_timer.expired_tscdeadline = 0;
    - guest_tsc = kvm_x86_ops->read_l1_tsc(vcpu, rdtsc());
    + guest_tsc = kvm_read_l1_tsc(vcpu, rdtsc());
    trace_kvm_wait_lapic_expire(vcpu->vcpu_id, guest_tsc - tsc_deadline);

    /* __delay is delay_tsc whenever the hardware has TSC, thus always. */
    @@ -1240,7 +1239,7 @@ static void start_apic_timer(struct kvm_lapic *apic)
    local_irq_save(flags);

    now = apic->lapic_timer.timer.base->get_time();
    - guest_tsc = kvm_x86_ops->read_l1_tsc(vcpu, rdtsc());
    + guest_tsc = kvm_read_l1_tsc(vcpu, rdtsc());
    if (likely(tscdeadline > guest_tsc)) {
    ns = (tscdeadline - guest_tsc) * 1000000ULL;
    do_div(ns, this_tsc_khz);
    diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
    index 239263f3..32ebe76 100644
    --- a/arch/x86/kvm/svm.c
    +++ b/arch/x86/kvm/svm.c
    @@ -3075,8 +3075,7 @@ static int cr8_write_interception(struct vcpu_svm *svm)
    static u64 svm_read_l1_tsc(struct kvm_vcpu *vcpu, u64 host_tsc)
    {
    struct vmcb *vmcb = get_host_vmcb(to_svm(vcpu));
    - return vmcb->control.tsc_offset +
    - kvm_scale_tsc(vcpu, host_tsc);
    + return vmcb->control.tsc_offset + host_tsc;
    }

    static int svm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
    diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
    index 7c372ad..d404a7e 100644
    --- a/arch/x86/kvm/x86.c
    +++ b/arch/x86/kvm/x86.c
    @@ -1427,6 +1427,12 @@ static u64 kvm_compute_tsc_offset(struct kvm_vcpu *vcpu, u64 target_tsc)
    return target_tsc - tsc;
    }

    +u64 kvm_read_l1_tsc(struct kvm_vcpu *vcpu, u64 host_tsc)
    +{
    + return kvm_x86_ops->read_l1_tsc(vcpu, kvm_scale_tsc(vcpu, host_tsc));
    +}
    +EXPORT_SYMBOL_GPL(kvm_read_l1_tsc);
    +
    void kvm_write_tsc(struct kvm_vcpu *vcpu, struct msr_data *msr)
    {
    struct kvm *kvm = vcpu->kvm;
    @@ -1750,7 +1756,7 @@ static int kvm_guest_time_update(struct kvm_vcpu *v)
    kernel_ns = get_kernel_ns();
    }

    - tsc_timestamp = kvm_x86_ops->read_l1_tsc(v, host_tsc);
    + tsc_timestamp = kvm_read_l1_tsc(v, host_tsc);

    /*
    * We may have to catch up the TSC to match elapsed wall clock
    @@ -6493,8 +6499,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
    if (hw_breakpoint_active())
    hw_breakpoint_restore();

    - vcpu->arch.last_guest_tsc = kvm_x86_ops->read_l1_tsc(vcpu,
    - rdtsc());
    + vcpu->arch.last_guest_tsc = kvm_read_l1_tsc(vcpu, rdtsc());

    vcpu->mode = OUTSIDE_GUEST_MODE;
    smp_wmb();
    diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
    index 2a21845..75ecb7c 100644
    --- a/include/linux/kvm_host.h
    +++ b/include/linux/kvm_host.h
    @@ -1146,6 +1146,8 @@ static inline void kvm_vcpu_set_dy_eligible(struct kvm_vcpu *vcpu, bool val)
    #endif /* CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT */

    u64 kvm_scale_tsc(struct kvm_vcpu *vcpu, u64 tsc);
    +u64 kvm_read_l1_tsc(struct kvm_vcpu *vcpu, u64 host_tsc);
    +
    extern struct kvm_x86_ops *kvm_x86_ops;

    static inline void adjust_tsc_offset_guest(struct kvm_vcpu *vcpu,
    --
    2.4.8


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