RE: [Xen-devel] [Patch] Add hardware CR8 acceleration for TPR accessing

["Cui, Dexuan" <dexuan.cui@xxxxxxxxx>]

Hi, Travis,
Is there anything in SVM similar to TPP-threshold in VMX?
If no, I really need to find a better place for the 
vlapic_update_tpr_threshold().

Thanks
 -- Dexuan

-----Original Message-----
From: Travis Betak [mailto:travis.betak@xxxxxxx] 
Sent: 2006年10月23日 21:23
To: Cui, Dexuan
Cc: Keir.Fraser@xxxxxxxxxxxx; xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Xen-devel] [Patch] Add hardware CR8 acceleration for TPR accessing

On Mon, 23 Oct 2006, Cui, Dexuan wrote:

> diff -r 8113c55a6efd xen/arch/x86/hvm/vlapic.c
> --- a/xen/arch/x86/hvm/vlapic.c       Sun Oct 22 17:38:59 2006 +0100
> +++ b/xen/arch/x86/hvm/vlapic.c       Mon Oct 23 14:03:11 2006 +0800
> @@ -29,6 +29,7 @@
>  #include <asm/hvm/hvm.h>
>  #include <asm/hvm/io.h>
>  #include <asm/hvm/support.h>
> +#include <asm/hvm/vmx/vmx.h>
>
>  #include <xen/lib.h>
>  #include <xen/sched.h>
> @@ -119,6 +120,20 @@ uint32_t vlapic_update_ppr(struct vlapic
>                  vlapic, ppr, isr, isrv);
>
>      return ppr;
> +}
> +
> +void vlapic_update_tpr_threshold(struct vlapic *vlapic)
> +{
> +#ifdef __x86_64__
> +    int highest_irr = vlapic_find_highest_irr(vlapic);
> +    int tpr = vlapic_get_reg(vlapic, APIC_TASKPRI) & 0xF0;
> +
> +    if ( highest_irr == -1 )
> +        __vmwrite( TPR_THRESHOLD, 0);
> +    else
> +        __vmwrite(TPR_THRESHOLD,
> +            highest_irr > tpr ? (tpr >> 4) : (highest_irr >> 4) );
> +#endif
>  }
>
>  /* This only for fixed delivery mode */

Hi, Dexuan,

Do we want architectual-specific code creeping into the generic HVM
layer?  This routine is only called in VMX code but I don't think this
the the right place for this code.

  --travis

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