Messages in this thread | | | Subject | Re: [PATCH 1/2] KVM: x86: implement KVM_SET_TSC_PRECISE/KVM_GET_TSC_PRECISE | From | Paolo Bonzini <> | Date | Mon, 30 Nov 2020 15:33:46 +0100 |
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On 30/11/20 14:35, Maxim Levitsky wrote: > + if (guest_cpuid_has(vcpu, X86_FEATURE_TSC_ADJUST)) { > + tsc_state.tsc_adjust = vcpu->arch.ia32_tsc_adjust_msr; > + tsc_state.flags |= KVM_TSC_STATE_TSC_ADJUST_VALID; > + }
This is mostly useful for userspace that doesn't disable the quirk, right?
> + kvm_get_walltime(&wall_nsec, &host_tsc); > + diff = wall_nsec - tsc_state.nsec; > + > + if (diff < 0 || tsc_state.nsec == 0) > + diff = 0; > +
diff < 0 should be okay. Also why the nsec==0 special case? What about using a flag instead?
Paolo
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