On Mon, Sep 21, 2015 at 4:53 PM, Julien Grall <julien.gr...@citrix.com> wrote:
> Hi Vijay,
>
> The only things I haven't check on this patch was the ITS command structure.
[...]
> Why a padding of only 56 bits? Shouldn't it be 248 bits (i.e 31 * 8
> bits) to fit all the command?
>
>> + } hdr;
>> + struct __packed {
>> + u8 cmd;
>> + u8 res1[3];
>> + u32 devid;
>> + u64 size:5;
>> + u64 res2:59;
>> + /* XXX: Though itt is 40 bit. Keep it 48 to avoid shift */
>> + u64 res3:8;
>
> It's very confusing for the reviewer to see a mix of usage (u8 res1[n],
> u64 res3:8) within the same structure.
>
> The later (i.e u64 field:n) is the best to use because we can match
> quickly the size with the spec.
>
Do you mean to convert all field type as 64 as below?
struct __packed {
u64 cmd:8;
u64 res:24;
u64 devid:32;
u64 size:5;
u64 res2:59;
/* XXX: Though itt is 40 bit. Keep it 48 to avoid shift */
u64 res3:8;
u64 itt:40;
u64 res4:15;
u64 valid:1;
u64 res5;
} mapd_cmd;
>> + u64 itt:40;
>> + u64 res4:15;
>> + u64 valid:1;
>> + u64 res5;
>> + } mapd;
>
> [..]
l
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