Re: [PATCH v8 1/2] xen+tools: Report Interrupt Controller Virtualization capabilities on x86

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Wed, Mar 16, 2022 at 09:13:14AM +0000, Jane Malalane wrote:
> diff --git a/xen/arch/x86/hvm/vmx/vmcs.c b/xen/arch/x86/hvm/vmx/vmcs.c
> index e1e1fa14e6..77ce0b2121 100644
> --- a/xen/arch/x86/hvm/vmx/vmcs.c
> +++ b/xen/arch/x86/hvm/vmx/vmcs.c
> @@ -343,6 +343,15 @@ static int vmx_init_vmcs_config(bool bsp)
>              MSR_IA32_VMX_PROCBASED_CTLS2, &mismatch);
>      }
>  
> +    /* Check whether hardware supports accelerated xapic and x2apic. */
> +    if ( bsp )
> +    {
> +        assisted_xapic_available = cpu_has_vmx_virtualize_apic_accesses;
> +        assisted_x2apic_available = cpu_has_vmx_virtualize_x2apic_mode &&
> +                                    (cpu_has_vmx_apic_reg_virt ||
> +                                     cpu_has_vmx_virtual_intr_delivery);
> +    }

I'm afraid using cpu_has_vmx_* is not correct here. The
vmx_secondary_exec_control variable hasn't been set here, so you will
need to move those checks to the end of the function, after
vmx_secondary_exec_control has been set.

Thanks, Roger.