> Hi Sean, > > We've rebased the SEV+SNP support onto your updated UPM base support > tree and things seem to be working okay, but we needed some fixups on > top of the base support get things working, along with 1 workaround > for an issue that hasn't been root-caused yet: > > https://github.com/mdroth/linux/commits/upmv10b-host-snp-v8-wip > > *stash (upm_base_support): mm: restrictedmem: Kirill's pinning implementation > *workaround (use_base_support): mm: restrictedmem: loosen exclusivity check What I'm seeing is Slot#3 gets added first and then deleted. When it's gets added, Slot#0 already has the same range bound to restrictedmem so trigger the exclusive check. This check is exactly the current code for. > *fixup (upm_base_support): KVM: use inclusive ranges for restrictedmem binding/unbinding > *fixup (upm_base_support): mm: restrictedmem: use inclusive ranges for issuing invalidations As many kernel APIs treat 'end' as exclusive, I would rather keep using exclusive 'end' for these APIs(restrictedmem_bind/restrictedmem_unbind and notifier callbacks) but fix it internally in the restrictedmem. E.g. all the places where xarray API needs a 'last'/'max' we use 'end - 1'. See below for the change. > *fixup (upm_base_support): KVM: fix restrictedmem GFN range calculations Subtracting slot->restrictedmem.index for start/end in restrictedmem_get_gfn_range() is the correct fix. > *fixup (upm_base_support): KVM: selftests: CoCo compilation fixes > > We plan to post an updated RFC for v8 soon, but also wanted to share > the staging tree in case you end up looking at the UPM integration aspects > before then. > > -Mike This is the restrictedmem fix to solve 'end' being stored and checked in xarray: --- a/mm/restrictedmem.c +++ b/mm/restrictedmem.c @@ -46,12 +46,12 @@ static long restrictedmem_punch_hole(struct restrictedmem *rm, int mode, */ down_read(&rm->lock); - xa_for_each_range(&rm->bindings, index, notifier, start, end) + xa_for_each_range(&rm->bindings, index, notifier, start, end - 1) notifier->ops->invalidate_start(notifier, start, end); ret = memfd->f_op->fallocate(memfd, mode, offset, len); - xa_for_each_range(&rm->bindings, index, notifier, start, end) + xa_for_each_range(&rm->bindings, index, notifier, start, end - 1) notifier->ops->invalidate_end(notifier, start, end); up_read(&rm->lock); @@ -224,7 +224,7 @@ static int restricted_error_remove_page(struct address_space *mapping, } spin_unlock(&inode->i_lock); - xa_for_each_range(&rm->bindings, index, notifier, start, end) + xa_for_each_range(&rm->bindings, index, notifier, start, end - 1) notifier->ops->error(notifier, start, end); break; } @@ -301,11 +301,12 @@ int restrictedmem_bind(struct file *file, pgoff_t start, pgoff_t end, if (exclusive != rm->exclusive) goto out_unlock; - if (exclusive && xa_find(&rm->bindings, &start, end, XA_PRESENT)) + if (exclusive && + xa_find(&rm->bindings, &start, end - 1, XA_PRESENT)) goto out_unlock; } - xa_store_range(&rm->bindings, start, end, notifier, GFP_KERNEL); + xa_store_range(&rm->bindings, start, end - 1, notifier, GFP_KERNEL); rm->exclusive = exclusive; ret = 0; out_unlock: @@ -320,7 +321,7 @@ void restrictedmem_unbind(struct file *file, pgoff_t start, pgoff_t end, struct restrictedmem *rm = file->f_mapping->private_data; down_write(&rm->lock); - xa_store_range(&rm->bindings, start, end, NULL, GFP_KERNEL); + xa_store_range(&rm->bindings, start, end - 1, NULL, GFP_KERNEL); synchronize_rcu(); up_write(&rm->lock); }
