On 10/26/2016 12:49 PM, Tian, Kevin wrote: >> From: Alex Williamson [mailto:alex.williamson@xxxxxxxxxx] >> Sent: Monday, October 24, 2016 10:32 AM >> >>>>> -static long vfio_unpin_pages(unsigned long pfn, long npage, >>>>> - int prot, bool do_accounting) >>>>> +static long __vfio_unpin_pages_remote(struct vfio_iommu *iommu, >>>>> + unsigned long pfn, long npage, int prot, >>>>> + bool do_accounting) >>>> >>>> Have you noticed that it's kind of confusing that >>>> __vfio_{un}pin_pages_remote() uses current, which does a >>>> get_user_pages_fast() while "local" uses a provided task_struct and >>>> uses get_user_pages_*remote*()? And also what was effectively local >>>> (ie. we're pinning for our own use here) is now "remote" and pinning >>>> for a remote, vendor driver consumer, is now "local". It's not very >>>> intuitive. >>>> > > I questioned this confusing naming in v8 too... > I do tried to address your concerns on v8. >>> >>> 'local' in local_domain was suggested to describe the domain for local >>> page tracking. Earlier suggestions to have 'mdev' or 'noimmu' in this >>> name were discarded. May be we should revisit what the name should be. >>> Any suggestion? >>> >>> For local_domain, to pin pages, flow is: >>> >>> for local_domain >>> |- vfio_pin_pages() >>> |- vfio_iommu_type1_pin_pages() >>> |- __vfio_pin_page_local() >>> |- vaddr_get_pfn(task->mm) >>> |- get_user_pages_remote() >>> >>> __vfio_pin_page_local() --> get_user_pages_remote() >> >> >> In vfio.c we have the concept of an external user, perhaps that could >> be continued here. An mdev driver would be an external, or remote >> pinning. >> > > I prefer to use remote here. It's aligned with underlying mm operations > Using 'remote' in this case is also confusing since it is already used in this file. I liked Alex's suggestion to use external and I'll have those changed in next version of patch set. Kirti -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
