Re: [Xen-devel] [RFC v1 06/15] vt-d: Extend struct iremap_entry to support VT-d Posted-Interrupts

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 27.03.15 at 02:53, <feng.wu@xxxxxxxxx> wrote:
>> From: Andrew Cooper [mailto:andrew.cooper3@xxxxxxxxxx]
>> Sent: Friday, March 27, 2015 3:01 AM
>> On 25/03/15 12:31, Feng Wu wrote:
>> > --- a/xen/drivers/passthrough/vtd/iommu.h
>> > +++ b/xen/drivers/passthrough/vtd/iommu.h
>> > @@ -303,6 +303,18 @@ struct iremap_entry {
>> >               res_2   : 8,
>> >               dst     : 32;
>> >       }lo;
>> > +    struct {
>> > +        u64 p       : 1,
>> > +            fpd     : 1,
>> > +            res_1   : 6,
>> > +            avail   : 4,
>> > +            res_2   : 2,
>> > +            urg     : 1,
>> > +            im      : 1,
>> > +            vector  : 8,
>> > +            res_3   : 14,
>> > +            pda_l   : 26;
>> > +    }lo_intpost;
>> >     };
>> >     union {
>> >       u64 hi_val;
>> > @@ -312,6 +324,13 @@ struct iremap_entry {
>> >               svt     : 2,
>> >               res_1   : 44;
>> >       }hi;
>> > +    struct {
>> > +        u64 sid     : 16,
>> > +            sq      : 2,
>> > +            svt     : 2,
>> > +            res_1   : 12,
>> > +            pda_h   : 32;
>> > +    }hi_intpost;
>> 
>> I would prefer if this union was reformatted as I suggested in the
>> thread from your design doc, but I won't insist on it as a blocker to entry.
> 
> Thanks for the comments. I also considered your sugguestion on the Design
> doc, here is your proposal:
> 
> struct iremap_entry {
>     union {
>         struct { u64 lo, hi; };
>         struct { <bitfields> } norm; (names subject to improvement)
>         struct { <bitfields> } post;
>     };
> };
> 
> Seems in that way, we need to change some existing code to adapt to
> this new structure. I am okay with both of them, but can we listen
> some voices form some others? Is it okay for you?

I think this would be a good move, but in the end it's the VT-d
maintainers who got to decide.

Jan


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