tree 8cf55a1022132806b63cceb24b286514c2210e34
parent 0699c64a4be6e4a6137240379a1f82c752e663d8
author Paolo Bonzini <pbonzini@redhat.com> 1555507724 +0200
committer Paolo Bonzini <pbonzini@redhat.com> 1556652135 +0200

KVM: fix KVM_CLEAR_DIRTY_LOG for memory slots of unaligned size

If a memory slot's size is not a multiple of 64 pages (256K), then
the KVM_CLEAR_DIRTY_LOG API is unusable: clearing the final 64 pages
either requires the requested page range to go beyond memslot->npages,
or requires log->num_pages to be unaligned, and kvm_clear_dirty_log_protect
requires log->num_pages to be both in range and aligned.

To allow this case, allow log->num_pages not to be a multiple of 64 if
it ends exactly on the last page of the slot.

Reported-by: Peter Xu <peterx@redhat.com>
Fixes: 98938aa8edd6 ("KVM: validate userspace input in kvm_clear_dirty_log_protect()", 2019-01-02)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>