Re: [PATCH] VMX, apicv: add boot parameter to enable/disable APIC-v dynamically

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 09/08/13 10:01, Yang Zhang wrote:
> From: Yang Zhang <yang.z.zhang@Intel.com>
>
> Add a boot parameter to enable/disable the APIC-v dynamically. APIC-v is
> enabled by default. User can use apicv=0 to disable it.
>
> Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
> ---

Please patch docs/misc/xen-command-line.markdown as well.

>  xen/arch/x86/hvm/vmx/vmcs.c |    7 +++++--
>  1 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/xen/arch/x86/hvm/vmx/vmcs.c b/xen/arch/x86/hvm/vmx/vmcs.c
> index de9f592..b52408d 100644
> --- a/xen/arch/x86/hvm/vmx/vmcs.c
> +++ b/xen/arch/x86/hvm/vmx/vmcs.c
> @@ -46,6 +46,9 @@ boolean_param("vpid", opt_vpid_enabled);
>  static bool_t __read_mostly opt_unrestricted_guest_enabled = 1;
>  boolean_param("unrestricted_guest", opt_unrestricted_guest_enabled);
>  
> +static bool_t __read_mostly opt_apicv_enabled = 1;
> +boolean_param("apicv", opt_apicv_enabled);
> +
>  /*
>   * These two parameters are used to config the controls for Pause-Loop Exiting:
>   * ple_gap:    upper bound on the amount of time between two successive
> @@ -196,12 +199,12 @@ static int vmx_init_vmcs_config(void)
>           * "APIC Register Virtualization" and "Virtual Interrupt Delivery"
>           * can be set only when "use TPR shadow" is set
>           */
> -        if ( _vmx_cpu_based_exec_control & CPU_BASED_TPR_SHADOW )
> +        if ( _vmx_cpu_based_exec_control & CPU_BASED_TPR_SHADOW &&
> +                opt_apicv_enabled )
>              opt |= SECONDARY_EXEC_APIC_REGISTER_VIRT |
>                     SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY |
>                     SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE;
>  
> -

Unrelated whitespace alteration.

~Andrew

>          _vmx_secondary_exec_control = adjust_vmx_controls(
>              "Secondary Exec Control", min, opt,
>              MSR_IA32_VMX_PROCBASED_CTLS2, &mismatch);