2016-09-21 10:14+0800, Wanpeng Li:
> From: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>
>
> 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.
>
> Suggested-by: Radim Krčmář <rkrcmar@xxxxxxxxxx>
> Suggested-by: Wincy Van <fanwenyi0529@xxxxxxxxx>
> Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> Cc: Radim Krčmář <rkrcmar@xxxxxxxxxx>
> Cc: Wincy Van <fanwenyi0529@xxxxxxxxx>
> Cc: Yang Zhang <yang.zhang.wz@xxxxxxxxx>
> Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>
> ---
> v2 -> v3:
> * introduce a new set of bitmaps and assign them in vmx_set_msr_bitmap()
> v1 -> v2:
> * leverage the cached msr bitmap
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> @@ -2518,10 +2520,18 @@ static void vmx_set_msr_bitmap(struct kvm_vcpu *vcpu)
> else if (cpu_has_secondary_exec_ctrls() &&
> (vmcs_read32(SECONDARY_VM_EXEC_CONTROL) &
> SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE)) {
> - if (is_long_mode(vcpu))
> - msr_bitmap = vmx_msr_bitmap_longmode_x2apic;
> - else
> - msr_bitmap = vmx_msr_bitmap_legacy_x2apic;
> + if (enable_apicv && kvm_vcpu_apicv_active(vcpu)) {
> + if (is_long_mode(vcpu))
> + msr_bitmap = vmx_msr_bitmap_longmode_x2apic;
> + else
> + msr_bitmap = vmx_msr_bitmap_legacy_x2apic;
> + } else if ((enable_apicv && !kvm_vcpu_apicv_active(vcpu)) ||
> + !enable_apicv) {
Could only be "else" without if here. I'll change that when refactoring
of vmx bitmap handling, posting soon (hopefully).
> + if (is_long_mode(vcpu))
> + msr_bitmap = vmx_msr_bitmap_longmode_x2apic_apicv_inactive;
> + else
> + msr_bitmap = vmx_msr_bitmap_legacy_x2apic_apicv_inactive;
> + }
> } else {
> if (is_long_mode(vcpu))
> msr_bitmap = vmx_msr_bitmap_longmode;
> @@ -4678,28 +4688,49 @@ static void vmx_disable_intercept_for_msr(u32 msr, bool longmode_only)
> -static void vmx_enable_intercept_msr_read_x2apic(u32 msr)
> +static void vmx_enable_intercept_msr_read_x2apic(u32 msr, bool apicv_active)
> {
> - __vmx_enable_intercept_for_msr(vmx_msr_bitmap_legacy_x2apic,
> - msr, MSR_TYPE_R);
> - __vmx_enable_intercept_for_msr(vmx_msr_bitmap_longmode_x2apic,
> - msr, MSR_TYPE_R);
> + if (apicv_active) {
> + __vmx_enable_intercept_for_msr(vmx_msr_bitmap_legacy_x2apic,
> + msr, MSR_TYPE_R);
> + __vmx_enable_intercept_for_msr(vmx_msr_bitmap_longmode_x2apic,
> + msr, MSR_TYPE_R);
> + } else {
> + __vmx_disable_intercept_for_msr(vmx_msr_bitmap_legacy_x2apic_apicv_inactive,
> + msr, MSR_TYPE_R);
> + __vmx_disable_intercept_for_msr(vmx_msr_bitmap_longmode_x2apic_apicv_inactive,
> + msr, MSR_TYPE_R);
Pasto here (disable vs. enable). It's not called with !apicv_active and
the refactoring will delete the whole function, so
Reviwed-by: Radim Krčmář <rkrcmar@xxxxxxxxxx>
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