This directory contains the implementation of a NVMe driver component.


Brief
=====

The driver supports PCIe NVMe devices matching at least revision 1.1 of
the NVMe specification. For now it only supports one name space and uses
one completion and one submission queue to handle all I/O requests; one
request is limited to 1MiB of data. It lacks any name space management
functionality.


Configuration
=============

The following config illustrates how the driver is configured:

!<start name="nvme_drv">
!  <resource name="ram" quantum="24M"/>
!  <provides><service name="Block"/></provides>
!  <config max_hmb_size="16M">
!    <policy label_prefix="client1" writeable="yes"/>
!  </config>
!</start>

The 'max_hmb_size' attribute instructs the driver to setup the
host-memory-buffer with at most 16 MiB of DMA-capable memory if such a
buffer is needed by the device. Should the value be less than the minimal
required amount of memory it will not be used and a warning is issued. On
the other hand, if the specified value is larger than the preferred amount
of memory as favored by the device it will be capped to that amount instead.


Report
======

The driver supports reporting of active name spaces, which can be enabled
via the configuration 'report' sub-node:

!<report namespace="yes"/>

The report structure is depicted by the following example:

!<controller model="QEMU NVMe Ctrl" serial="FNRD">
! <namespace id="0" block_count="32768" block_size="512"/>
!</controller>
