Re: [PATCH v3 2/6] KVM: x86: Allow vendor code to disable quirks

[Yan Zhao]

> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 35d03fcdb8e9..5abea6c73a38 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -9775,6 +9775,7 @@ int kvm_x86_vendor_init(struct kvm_x86_init_ops *ops)
>  		kvm_host.xcr0 = xgetbv(XCR_XFEATURE_ENABLED_MASK);
>  		kvm_caps.supported_xcr0 = kvm_host.xcr0 & KVM_SUPPORTED_XCR0;
>  	}
> +	kvm_caps.inapplicable_quirks = KVM_X86_CONDITIONAL_QUIRKS;
>  
>  	rdmsrl_safe(MSR_EFER, &kvm_host.efer);
>  
> @@ -12754,6 +12755,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
>  	kvm->arch.apic_bus_cycle_ns = APIC_BUS_CYCLE_NS_DEFAULT;
>  	kvm->arch.guest_can_read_msr_platform_info = true;
>  	kvm->arch.enable_pmu = enable_pmu;
> +	kvm->arch.disabled_quirks = kvm_caps.inapplicable_quirks;
Should be

kvm->arch.disabled_quirks |= kvm_caps.inapplicable_quirks;

Otherwise, it may overwrite the disabled_quirks value set in vm_init hook.

>  
>  #if IS_ENABLED(CONFIG_HYPERV)
>  	spin_lock_init(&kvm->arch.hv_root_tdp_lock);