Messages in this thread | | | Subject | Re: [PATCH 1/4] vdpa: introduce config op to get valid iova range | From | Jason Wang <> | Date | Tue, 11 Aug 2020 10:53:09 +0800 |
| |
On 2020/8/10 下午8:05, Michael S. Tsirkin wrote: > On Thu, Aug 06, 2020 at 03:43:54PM +0300, Eli Cohen wrote: >> On Thu, Aug 06, 2020 at 08:29:22AM -0400, Michael S. Tsirkin wrote: >>> On Thu, Aug 06, 2020 at 03:03:55PM +0300, Eli Cohen wrote: >>>> On Wed, Aug 05, 2020 at 08:51:56AM -0400, Michael S. Tsirkin wrote: >>>>> On Wed, Jun 17, 2020 at 11:29:44AM +0800, Jason Wang wrote: >>>>>> This patch introduce a config op to get valid iova range from the vDPA >>>>>> device. >>>>>> >>>>>> Signed-off-by: Jason Wang <jasowang@redhat.com> >>>>>> --- >>>>>> include/linux/vdpa.h | 14 ++++++++++++++ >>>>>> 1 file changed, 14 insertions(+) >>>>>> >>>>>> diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h >>>>>> index 239db794357c..b7633ed2500c 100644 >>>>>> --- a/include/linux/vdpa.h >>>>>> +++ b/include/linux/vdpa.h >>>>>> @@ -41,6 +41,16 @@ struct vdpa_device { >>>>>> unsigned int index; >>>>>> }; >>>>>> >>>>>> +/** >>>>>> + * vDPA IOVA range - the IOVA range support by the device >>>>>> + * @start: start of the IOVA range >>>>>> + * @end: end of the IOVA range >>>>>> + */ >>>>>> +struct vdpa_iova_range { >>>>>> + u64 start; >>>>>> + u64 end; >>>>>> +}; >>>>>> + >>>>> >>>>> This is ambiguous. Is end in the range or just behind it? >>>>> How about first/last? >>>> It is customary in the kernel to use start-end where end corresponds to >>>> the byte following the last in the range. See struct vm_area_struct >>>> vm_start and vm_end fields >>> Exactly my point: >>> >>> include/linux/mm_types.h: unsigned long vm_end; /* The first byte after our end address >>> >>> in this case Jason wants it to be the last byte, not one behind. >>> >>> >> Maybe start, size? Not ambiguous, and you don't need to do annoying >> calculations like size = last - start + 1 > Size has a bunch of issues: can overlap, can not cover the entire 64 bit > range. The requisite checks are arguably easier to get wrong than > getting the size if you need it.
Yes, so do you still prefer first/last or just begin/end which is consistent with iommu_domain_geometry?
Thanks
>
| |