Re: [PATCH for-4.21??? 2/3] x86/vLAPIC: drop VLAPIC_VERSION

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

On Wed, Oct 08, 2025 at 02:08:48PM +0200, Jan Beulich wrote:
> In preparation of making the value somewhat dynamic drop the constant.
> Replace its use in guest_wrmsr_x2apic() by actually fetching the LVR
> value.
> 
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> 
> --- a/xen/arch/x86/hvm/vlapic.c
> +++ b/xen/arch/x86/hvm/vlapic.c
> @@ -31,7 +31,6 @@
>  #include <public/hvm/ioreq.h>
>  #include <public/hvm/params.h>
>  
> -#define VLAPIC_VERSION                  0x00050014
>  #define LVT_BIAS(reg)                   (((reg) - APIC_LVTT) >> 4)
>  
>  #define LVTS \
> @@ -1015,7 +1014,7 @@ int guest_wrmsr_x2apic(struct vcpu *v, u
>      case APIC_SPIV:
>          if ( val & ~(APIC_VECTOR_MASK | APIC_SPIV_APIC_ENABLED |
>                       APIC_SPIV_FOCUS_DISABLED |
> -                     (VLAPIC_VERSION & APIC_LVR_DIRECTED_EOI
> +                     (vlapic_get_reg(vlapic, APIC_LVR) & 
> APIC_LVR_DIRECTED_EOI
>                        ? APIC_SPIV_DIRECTED_EOI : 0)) )
>              return X86EMUL_EXCEPTION;
>          break;
> @@ -1439,7 +1438,7 @@ static void vlapic_do_init(struct vlapic
>      if ( !has_vlapic(vlapic_vcpu(vlapic)->domain) )
>          return;
>  
> -    vlapic_set_reg(vlapic, APIC_LVR, VLAPIC_VERSION);
> +    vlapic_set_reg(vlapic, APIC_LVR, 0x00050014);

(Maybe I'm getting ahead of patch 3, as I haven't looked yet)

Don't we want to use some kind of macros to build this in a more
friendly way?

We could have a pair of SET_APIC_{VERSION,MAXLVT}()?

Thanks, Roger.