We currently store tags in a separate region of physical memory, though you could imagine "borrowing" ECC bits. A tag cache (which due to the small size of tags

We currently store tags in a separate region of physical memory, though you could imagine "borrowing" ECC bits. A tag cache (which due to the small size of tags can have a large reach) reduces the number of instances where you might have read or write multiplication. We're about to start work on further optimisations on this.