Re: [PATCH 6/6] KVM: VMX: enable IPI virtualization

[Paolo Bonzini]

On 16/07/21 08:48, Zeng Guang wrote:
>  
> +	if (!(_cpu_based_3rd_exec_control & TERTIARY_EXEC_IPI_VIRT))
> +		enable_ipiv = 0;
> +
>   	}

Please move this to hardware_setup(), using a new function 
cpu_has_vmx_ipiv() in vmx/capabilities.h.

>  	if (_cpu_based_exec_control & CPU_BASED_ACTIVATE_TERTIARY_CONTROLS) {
> -		u64 opt3 = 0;
> +		u64 opt3 = enable_ipiv ? TERTIARY_EXEC_IPI_VIRT : 0;
>  		u64 min3 = 0;

I like the idea of changing opt3, but it's different from how 
setup_vmcs_config works for the other execution controls.  Let me think 
if it makes sense to clean this up, and move the handling of other 
module parameters from hardware_setup() to setup_vmcs_config().

> +
> +	if (vmx->ipiv_active)
> +		install_pid(vmx);

This should be if (enable_ipiv) instead, I think.

In fact, in all other places that are using vmx->ipiv_active, you can 
actually replace it with enable_ipiv; they are all reached only with 
kvm_vcpu_apicv_active(vcpu) == true.

> +	if (!enable_apicv) {
> +		enable_ipiv = 0;
> +		vmcs_config.cpu_based_3rd_exec_ctrl &= ~TERTIARY_EXEC_IPI_VIRT;
> +	}

The assignment to vmcs_config.cpu_based_3rd_exec_ctrl should not be 
necessary; kvm_vcpu_apicv_active will always be false in that case and 
IPI virtualization would never be enabled.

Paolo