Re: [PATCH v8 4/5] hw/mem/cxl-type3: Add CXL CDAT Data Object Exchange

[Gregory Price <gregory.price@memverge.com>]

If you're expecting this to be dynamic in size in the future, then maybe
what we really want here is a function

static int ct3_get_cdat_size(CXLType3Dev ct3d) {
    /* TODO: Dynamic sizing calculations */
    return CT3_CDAT_NUM_ENTRIES;
}


On Thu, Oct 13, 2022 at 06:21:44PM +0100, Jonathan Cameron wrote:
> On Thu, 13 Oct 2022 13:09:26 -0400
> "Michael S. Tsirkin" <mst@redhat.com> wrote:
> 
> > On Thu, Oct 13, 2022 at 12:26:58PM -0400, Gregory Price wrote:
> > > Other than the nitpicks below, lgtm.  Not sure if you need a sign off
> > > from me given the contributions:
> > > 
> > > Signed-off-by: Gregory Price <gregory.price@memverge.com>
> > >   
> > > > +/* If no cdat_table == NULL returns number of entries */
> > > > +static int ct3_build_cdat_entries_for_mr(CDATSubHeader **cdat_table,
> > > > +                                         int dsmad_handle, MemoryRegion *mr)
> > > > +{
> > > > +    enum {
> > > > +        DSMAS,
> > > > +        DSLBIS0,
> > > > +        DSLBIS1,
> > > > +        DSLBIS2,
> > > > +        DSLBIS3,
> > > > +        DSEMTS,
> > > > +        NUM_ENTRIES
> > > > +    };  
> > > // ...  
> > > > +    if (!cdat_table) {
> > > > +        return NUM_ENTRIES;
> > > > +    }  
> > > 
> > > the only thing that i would recommend is making this enum global (maybe
> > > renaming them CT3_CDAT_[ENTRY_NAME]) and using CT3_CDAT_NUM_ENTRIES
> > > directly in the function that allocates the cdat buffer itself.  
> > 
> > 
> > Yes I think I agree here.
> 
> Ok, seems a consensus against having this local.
> 
> I can do this for now and then revisit if / when things become more complex
> and this becomes not global.  I guess a potential case of premature flexibility.
> 
> Jonathan
> 
> > 
> > > I do
> > > understand the want to keep the enum and the code creating the entries
> > > co-located though, so i'm just nitpicking here i guess.
> > > 
> > > Generally I dislike the pattern of passing a NULL into a function to get
> > > configuration data, and then calling that function again.  This function
> > > wants to be named...
> > > 
> > > ct3_build_cdat_entries_for_mr_or_get_table_size_if_cdat_is_null(...)
> > > 
> > > to accurately describe what it does.  Just kinda feels like an extra
> > > function call for no reason.
> > > 
> > > But either way, it works, this is just a nitpick on my side.
> > >   
> > > > +static int ct3_build_cdat_table(CDATSubHeader ***cdat_table, void *priv)
> > > > +{
> > > > +    g_autofree CDATSubHeader **table = NULL;
> > > > +    CXLType3Dev *ct3d = priv;
> > > > +    MemoryRegion *volatile_mr;
> > > > +    /* ... snip ... */
> > > > +}  
> > > 
> > > s/volatile/nonvolatile  
> > 
>