Messages in this thread | | | Subject | Re: [PATCH 1/2] KVM: X86: TSCDEADLINE MSR emulation fastpath | From | Paolo Bonzini <> | Date | Wed, 22 Apr 2020 10:38:39 +0200 |
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On 22/04/20 02:48, Wanpeng Li wrote: > On Tue, 21 Apr 2020 at 19:37, Paolo Bonzini <pbonzini@redhat.com> wrote: >> On 21/04/20 13:20, Wanpeng Li wrote: >>> + case MSR_IA32_TSCDEADLINE: >>> + if (!kvm_x86_ops.event_needs_reinjection(vcpu)) { >>> + data = kvm_read_edx_eax(vcpu); >>> + if (!handle_fastpath_set_tscdeadline(vcpu, data)) >>> + ret = EXIT_FASTPATH_CONT_RUN; >>> + } >>> break; >> Can you explain the event_needs_reinjection case? Also, does this break > This is used to catch the case vmexit occurred while another event was > being delivered to guest software, I move the > vmx_exit_handlers_fastpath() call after vmx_complete_interrupts() > which will decode such event and make kvm_event_needs_reinjection > return true.
This doesn't need a callback, kvm_event_needs_reinjection should be enough.
You should also check other conditions such as
vcpu->mode == EXITING_GUEST_MODE || kvm_request_pending(vcpu) || need_resched() || signal_pending(current)
before doing CONT_RUN.
>> AMD which does not implement the callback? > Now I add the tscdeadline msr emulation and vmx-preemption timer > fastpath pair for Intel platform.
But this would cause a crash if you run on AMD.
Paolo
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