Il 14/01/2014 10:22, Vadim Rozenfeld ha scritto:
> @@ -1883,6 +1884,13 @@ static int set_msr_hyperv_pw(struct kvm_vcpu *vcpu, u32 msr, u64 data)
> addr = gfn_to_hva(kvm, gfn);
> if (kvm_is_error_hva(addr))
> return 1;
> + if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC)
> + && ka->use_master_clock) {
> + tsc_ref.tsc_sequence = 1;
I think that after the first migration the sequence number will always
be 2: set_msr_hyperv_pw will set it to 1, and KVM_SET_KVMCLOCK will
increment it. Can you check this?
The solution would be to propagate the "struct msr_data *" argument from
kvm_set_msr_common to kvm_set_msr_hyper_pw. Then, here in this "if" you
can test msr_info->host_initiated, and increment the tsc_sequence
instead of resetting. Like
if ((!msr_info->host_initiated || tsc_ref.tsc_sequence) &&
boot_cpu_has(X86_FEATURE_CONSTANT_TSC) &&
ka->use_master_clock) {
tsc_ref.tsc_sequence = msr_info->host_initiated
? tsc_ref.tsc_sequence + 1
: 1;
> + tsc_ref.tsc_scale = ((10000LL << 32) /
> + vcpu->arch.virtual_tsc_khz) << 32;
> + tsc_ref.tsc_offset = kvm->arch.kvmclock_offset;
> + }
> if (__copy_to_user((void __user *)addr, &tsc_ref, sizeof(tsc_ref)))
> return 1;
> mark_page_dirty(kvm, gfn);
> @@ -3871,6 +3879,27 @@ long kvm_arch_vm_ioctl(struct file *filp,
> local_irq_enable();
> kvm->arch.kvmclock_offset = delta;
> kvm_gen_update_masterclock(kvm);
> + if (kvm->arch.hv_tsc_page & HV_X64_MSR_TSC_REFERENCE_ENABLE) {
> + HV_REFERENCE_TSC_PAGE tsc_ref;
> + struct kvm_arch *ka = &kvm->arch;
> + r = kvm_read_guest(kvm, kvm->arch.hv_tsc_page,
> + &tsc_ref, sizeof(tsc_ref));
> + if (r)
> + goto out;
> + if (tsc_ref.tsc_sequence
> + && boot_cpu_has(X86_FEATURE_CONSTANT_TSC)
> + && ka->use_master_clock) {
> + tsc_ref.tsc_sequence++;
> + tsc_ref.tsc_scale = ((10000LL << 32) /
> + __get_cpu_var(cpu_tsc_khz)) << 32;
Since on migration kvm_set_hyperv_pw will always be called, do you need
to write tsc_ref.scale at all here?
Paolo
> + tsc_ref.tsc_offset = kvm->arch.kvmclock_offset;
> + } else
> + tsc_ref.tsc_sequence = 0;
> + r = kvm_write_guest(kvm, kvm->arch.hv_tsc_page,
> + &tsc_ref, sizeof(tsc_ref));
> + if (r)
> + goto out;
> + }
> break;
> }
> case KVM_GET_CLOCK: {
>
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