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Re: [PATCH] KVM: VMX: Enable MSR-BASED TPR shadow even if w/o APICv

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2016-09-15 12:08 GMT+08:00 Mika Penttilä <mika.penttila@nextfour.com>:
> On 09/14/2016 10:58 AM, Wanpeng Li wrote:
>> From: Wanpeng Li <wanpeng.li@hotmail.com>
>>
>> I observed that kvmvapic(to optimize flexpriority=N or AMD) is used
>> to boost TPR access when testing kvm-unit-test/eventinj.flat tpr case
>> on my haswell desktop (w/ flexpriority, w/o APICv). Commit (8d14695f9542
>> x86, apicv: add virtual x2apic support) disable virtual x2apic mode
>> completely if w/o APICv, and the author also told me that windows guest
>> can't enter into x2apic mode when he developed the APICv feature several
>> years ago. However, it is not truth currently, Interrupt Remapping and
>> vIOMMU is added to qemu and the developers from Intel test windows 8 can
>> work in x2apic mode w/ Interrupt Remapping enabled recently.
>>
>> This patch enables TPR shadow for virtual x2apic mode to boost
>> windows guest in x2apic mode even if w/o APICv.
>>
>> Can pass the kvm-unit-test.
>>
>
> While at it, is the vmx flexpriotity stuff still valid code?
> AFAICS it gets enabled iff TPR shadow is on. flexpriority
> is on when :
>
> (flexpriority_enabled && lapic_in_kernel && cpu_has_vmx_tpr_shadow && cpu_has_vmx_virtualize_apic_accesses)
>
> But apic accesses to TPR mmio are not then trapped and TPR changes not reported because
> the “use TPR shadow” VM-execution control is 1.

Please note the patch is for MSR-BASED TPR shadow w/o APICv, TPR
shadow can work correctly in other configurations.

Regards,
Wanpeng Li

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[PATCH] KVM: VMX: Enable MSR-BASED TPR shadow even if w/o APICv Wanpeng Li <kernellwp@gmail.com> - 2016-09-14 10:00 +0200
  Re: [PATCH] KVM: VMX: Enable MSR-BASED TPR shadow even if w/o APICv Paolo Bonzini <pbonzini@redhat.com> - 2016-09-14 11:50 +0200
    Re: [PATCH] KVM: VMX: Enable MSR-BASED TPR shadow even if w/o APICv Radim Krčmář <rkrcmar@redhat.com> - 2016-09-14 14:10 +0200
      Re: [PATCH] KVM: VMX: Enable MSR-BASED TPR shadow even if w/o APICv Wanpeng Li <kernellwp@gmail.com> - 2016-09-15 03:20 +0200
        Re: [PATCH] KVM: VMX: Enable MSR-BASED TPR shadow even if w/o APICv Paolo Bonzini <pbonzini@redhat.com> - 2016-09-15 08:30 +0200
          Re: [PATCH] KVM: VMX: Enable MSR-BASED TPR shadow even if w/o APICv Wanpeng Li <kernellwp@gmail.com> - 2016-09-15 08:50 +0200
      Re: [PATCH] KVM: VMX: Enable MSR-BASED TPR shadow even if w/o APICv Wanpeng Li <kernellwp@gmail.com> - 2016-09-15 09:10 +0200
        Re: [PATCH] KVM: VMX: Enable MSR-BASED TPR shadow even if w/o APICv Radim Krčmář <rkrcmar@redhat.com> - 2016-09-15 18:00 +0200
          Re: [PATCH] KVM: VMX: Enable MSR-BASED TPR shadow even if w/o APICv Wanpeng Li <kernellwp@gmail.com> - 2016-09-18 09:00 +0200
            Re: [PATCH] KVM: VMX: Enable MSR-BASED TPR shadow even if w/o APICv Wanpeng Li <kernellwp@gmail.com> - 2016-09-18 09:00 +0200
            Re: [PATCH] KVM: VMX: Enable MSR-BASED TPR shadow even if w/o APICv Radim Krčmář <rkrcmar@redhat.com> - 2016-09-19 15:50 +0200
              Re: [PATCH] KVM: VMX: Enable MSR-BASED TPR shadow even if w/o APICv Wanpeng Li <kernellwp@gmail.com> - 2016-09-20 02:20 +0200
              Re: [PATCH] KVM: VMX: Enable MSR-BASED TPR shadow even if w/o APICv Wanpeng Li <kernellwp@gmail.com> - 2016-09-22 08:50 +0200
    Re: [PATCH] KVM: VMX: Enable MSR-BASED TPR shadow even if w/o APICv Wanpeng Li <kernellwp@gmail.com> - 2016-09-15 02:10 +0200
      Re: [PATCH] KVM: VMX: Enable MSR-BASED TPR shadow even if w/o APICv Wanpeng Li <kernellwp@gmail.com> - 2016-09-15 02:20 +0200
  Re: [PATCH] KVM: VMX: Enable MSR-BASED TPR shadow even if w/o APICv Wanpeng Li <kernellwp@gmail.com> - 2016-09-15 06:30 +0200
  Re: [PATCH] KVM: VMX: Enable MSR-BASED TPR shadow even if w/o APICv Paolo Bonzini <pbonzini@redhat.com> - 2016-09-15 08:40 +0200

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