| # Pinned Memory Token |
| |
| ## NAME |
| |
| pinned_memory_token - Representation of a device DMA grant |
| |
| ## SYNOPSIS |
| |
| Pinned Memory Tokens (PMTs) represent an outstanding acccess grant to a device |
| for performing DMA. |
| |
| ## DESCRIPTION |
| |
| PMTs are obtained by [pinning memory with a BTI object](../syscalls/bti_pin.md). |
| It is valid for the device associated with the BTI to access the memory represented |
| by the PMT for as long as the PMT object is around. When the PMT object is |
| destroyed, either via **zx_handle_close**(), **zx_pmt_unpin**(), or process |
| termination, access to the represented memory becomes illegal (this is |
| enforced by hardware on systems with the capability to do so, such as IOMMUs). |
| |
| TODO(teisenbe): Describe quarantining |
| |
| ## SEE ALSO |
| |
| + [bus_transaction_initiator](bus_transaction_initiator.md) - Bus Transaction Initiators |
| |
| ## SYSCALLS |
| |
| + [bti_pin](../syscalls/bti_pin.md) - pin memory and grant access to it to the BTI |
| + [pmt_unpin](../syscalls/pmt_unpin.md) - revoke access and unpin memory |
