On 06.09.21 17:51, Jan Beulich wrote:
> On 03.09.2021 12:08, Oleksandr Andrushchenko wrote:
>> @@ -37,12 +41,28 @@ static int map_range(unsigned long s, unsigned long e,
>> void *data,
>> unsigned long *c)
>> {
>> const struct map_data *map = data;
>> + gfn_t start_gfn;
>> int rc;
>>
>> for ( ; ; )
>> {
>> unsigned long size = e - s + 1;
>>
>> + /*
>> + * Any BAR may have holes in its memory we want to map, e.g.
>> + * we don't want to map MSI regions which may be a part of that BAR,
>> + * e.g. when a single BAR is used for both MMIO and MSI.
>> + * In this case MSI regions are subtracted from the mapping, but
>> + * map->start_gfn still points to the very beginning of the BAR.
>> + * So if there is a hole present then we need to adjust start_gfn
>> + * to reflect the fact of that substraction.
>> + */
>> + start_gfn = gfn_add(map->start_gfn, s - mfn_x(map->start_mfn));
> I may be missing something, but don't you need to adjust "size" then
> as well?
No, as range sets get consumed we have e and s updated accordingly,
so each time size represents the right value.
> And don't you need to account for the "hole" not being at
> the start?
We only have MMIO ranges here and all the ranges have their start set
appropriately
> (As an aside - do you mean "MSI-X regions" everywhere you
> say just "MSI" above?)
Yes, I mean MSI-X: will update
>
> Jan
>
