Re: [Xen-devel] [PATCH v9 12/25] x86: refactor psr: L3 CAT: set value: implement cos id picking flow.

[Yi Sun <yi.y.sun@xxxxxxxxxxxxxxx>]

On 17-03-29 03:57:52, Jan Beulich wrote:
> >>> On 29.03.17 at 03:36, <yi.y.sun@xxxxxxxxxxxxxxx> wrote:
> > On 17-03-29 09:20:21, Yi Sun wrote:
> >> On 17-03-28 06:20:48, Jan Beulich wrote:
> >> > >>> On 28.03.17 at 13:59, <yi.y.sun@xxxxxxxxxxxxxxx> wrote:
> >> > > I think we at least need a 'get_val()' hook.
> >> > 
> >> > Of course.
> >> > 
> >> > > I try to implement CAT/CDP hook.
> >> > > Please help to check if this is what you thought.
> >> > 
> >> > One remark below, but other than that - yes.
> >> > 
> >> > > static void cat_get_val(const struct feat_node *feat, unsigned int cos,
> >> > >                         enum cbm_type type, int flag, uint32_t *val)
> >> > > {
> >> > >     *val = feat->cos_reg_val[cos];
> >> > > }
> >> > > 
> >> > > static void l3_cdp_get_val(const struct feat_node *feat, unsigned int 
> >> > > cos,
> >> > >                            enum cbm_type type, int flag, uint32_t *val)
> >> > > {
> >> > >     if ( type == PSR_CBM_TYPE_L3_DATA || flag == 0 )
> >> > >         *val = get_cdp_data(feat, cos);
> >> > >     if ( type == PSR_CBM_TYPE_L3_CODE || flag == 1 )
> >> > >         *val = get_cdp_code(feat, cos);
> >> > > }
> >> > 
> >> > Why the redundancy between type and flag?
> >> > 
> >> For psr_get_val, upper layer input the cbm_type to get either DATA or CODE
> >> value. For other cases, we use flag as cos_num index to get either DATA or
> >> CODE.
> >> 
> > Let me explain more to avoid confusion. For other cases, we use cos_num as
> > index to get values from a feature. In these cases, we do not know the
> > cbm_type of the feature. So, I use the cos_num as flag to make 'get_val'
> > know which value should be returned.
> 
> I'm pretty sure this redundancy can be avoided.
> 
Then, I think I have to reuse the 'type'. As only CDP needs type to decide
which value to be returned so far, I think I can implement codes like below
to make CDP can handle all scenarios.

static void l3_cdp_get_val(const struct feat_node *feat, unsigned int cos,
                           enum cbm_type type, uint32_t *val)
{
    if ( type == PSR_CBM_TYPE_L3_DATA || flag == 0xF000 )
        *val = get_cdp_data(feat, cos);
    if ( type == PSR_CBM_TYPE_L3_CODE || flag == 0xF001 )
        *val = get_cdp_code(feat, cos);
}

static bool fits_cos_max(...)
{
......
    for (i = 0; i < feat->props->cos_num; i++)
    {
        feat->props->get_val(feat, cos, i + 0xF000, &default_val);
        if ( val[i] == default_val )
            ......
    }
......
}

Is that good for you?

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