From: Klaus Jensen <k.jen...@samsung.com> Remove the docs/specs/nvme.txt and replace it with proper documentation in docs/system/nvme.rst.
Signed-off-by: Klaus Jensen <k.jen...@samsung.com> Reviewed-by: Philippe Mathieu-Daudé <phi...@redhat.com> --- docs/specs/nvme.txt | 23 ----- docs/system/index.rst | 1 + docs/system/nvme.rst | 225 ++++++++++++++++++++++++++++++++++++++++++ MAINTAINERS | 2 +- 4 files changed, 227 insertions(+), 24 deletions(-) delete mode 100644 docs/specs/nvme.txt create mode 100644 docs/system/nvme.rst diff --git a/docs/specs/nvme.txt b/docs/specs/nvme.txt deleted file mode 100644 index 56d393884e7a..000000000000 --- a/docs/specs/nvme.txt +++ /dev/null @@ -1,23 +0,0 @@ -NVM Express Controller -====================== - -The nvme device (-device nvme) emulates an NVM Express Controller. - - -Reference Specifications ------------------------- - -The device currently implements most mandatory features of NVMe v1.3d, see - - https://nvmexpress.org/resources/specifications/ - -for the specification. - - -Known issues ------------- - -* The accounting numbers in the SMART/Health are reset across power cycles - -* Interrupt Coalescing is not supported and is disabled by default in volation - of the specification. diff --git a/docs/system/index.rst b/docs/system/index.rst index 02d07071810f..b05af716a973 100644 --- a/docs/system/index.rst +++ b/docs/system/index.rst @@ -23,6 +23,7 @@ Contents: net virtio-net-failover usb + nvme ivshmem linuxboot generic-loader diff --git a/docs/system/nvme.rst b/docs/system/nvme.rst new file mode 100644 index 000000000000..f7f63d6bf615 --- /dev/null +++ b/docs/system/nvme.rst @@ -0,0 +1,225 @@ +============== +NVMe Emulation +============== + +QEMU provides NVMe emulation through the ``nvme``, ``nvme-ns`` and +``nvme-subsys`` devices. + +See the following sections for specific information on + + * `Adding NVMe Devices`_, `additional namespaces`_ and `NVM subsystems`_. + * Configuration of `Optional Features`_ such as `Controller Memory Buffer`_, + `Simple Copy`_, `Zoned Namespaces`_, `metadata`_ and `End-to-End Data + Protection`_, + +Adding NVMe Devices +=================== + +Controller Emulation +-------------------- + +The QEMU emulated NVMe controller implements version 1.4 of the NVM Express +specification. All mandatory features are implement with a couple of exceptions +and limitations: + + * Accounting numbers in the SMART/Health log page are reset when the device + is power cycled. + * Interrupt Coalescing is not supported and is disabled by default. + +The simplest way to attach an NVMe controller on the QEMU PCI bus is to add the +following parameters: + +.. code-block:: console + + -drive file=nvm.img,if=none,id=nvm + -device nvme,serial=deadbeef,drive=nvm + +There are a number of optional general parameters for the ``nvme`` device. Some +are mentioned here, but see ``-device nvme,help`` to list all possible +parameters. + +``max_ioqpairs=UINT32`` (default: ``64``) + Set the maximum number of allowed I/O queue pairs. This replaces the + deprecated ``num_queues`` parameter. + +``msix_qsize=UINT16`` (default: ``65``) + The number of MSI-X vectors that the device should support. + +``mdts=UINT8`` (default: ``7``) + Set the Maximum Data Transfer Size of the device. + +``use-intel-id`` (default: ``off``) + Since QEMU 5.2, the device uses a QEMU allocated "Red Hat" PCI Device and + Vendor ID. Set this to ``on`` to revert to the unallocated Intel ID + previously used. + +Additional Namespaces +--------------------- + +In the simplest possible invocation sketched above, the device only support a +single namespace with the namespace identifier ``1``. To support multiple +namespaces and additional features, the ``nvme-ns`` device must be used. + +.. code-block:: console + + -device nvme,id=nvme-ctrl-0,serial=deadbeef + -drive file=nvm-1.img,if=none,id=nvm-1 + -device nvme-ns,drive=nvm-1 + -drive file=nvm-2.img,if=none,id=nvm-2 + -device nvme-ns,drive=nvm-2 + +The namespaces defined by the ``nvme-ns`` device will attach to the most +recently defined ``nvme-bus`` that is created by the ``nvme`` device. Namespace +identifers are allocated automatically, starting from ``1``. + +There are a number of parameters available: + +``nsid`` (default: ``0``) + Explicitly set the namespace identifier. + +``uuid`` (default: *autogenerated*) + Set the UUID of the namespace. This will be reported as a "Namespace UUID" + descriptor in the Namespace Identification Descriptor List. + +``bus`` + If there are more ``nvme`` devices defined, this parameter may be used to + attach the namespace to a specific ``nvme`` device (identified by an ``id`` + parameter on the controller device). + +NVM Subsystems +-------------- + +Additional features becomes available if the controller device (``nvme``) is +linked to an NVM Subsystem device (``nvme-subsys``). + +The NVM Subsystem emulation allows features such as shared namespaces and +multipath I/O. + +.. code-block:: console + + -device nvme-subsys,id=nvme-subsys-0,nqn=subsys0 + -device nvme,serial=a,subsys=nvme-subsys-0 + -device nvme,serial=b,subsys=nvme-subsys-0 + +This will create an NVM subsystem with two controllers. Having controllers +linked to an ``nvme-subsys`` device allows additional ``nvme-ns`` parameters: + +``shared`` (default: ``off``) + Specifies that the namespace will be attached to all controllers in the + subsystem. If set to ``off`` (the default), the namespace will remain a + private namespace and may only be attached to a single controller at a time. + +``detached`` (default: ``off``) + If set to ``on``, the namespace will be be available in the subsystem, but + not attached to any controllers initially. + +Thus, adding + +.. code-block:: console + + -drive file=nvm-1.img,if=none,id=nvm-1 + -device nvme-ns,drive=nvm-1,nsid=1,shared=on + -drive file=nvm-2.img,if=none,id=nvm-2 + -device nvme-ns,drive=nvm-2,nsid=3,detached=on + +will cause NSID 1 will be a shared namespace (due to ``shared=on``) that is +initially attached to both controllers. NSID 3 will be a private namespace +(i.e. only attachable to a single controller at a time) and will not be +attached to any controller initially (due to ``detached=on``). + +Optional Features +================= + +Controller Memory Buffer +------------------------ + +``nvme`` device parameters related to the Controller Memory Buffer support: + +``cmb_size_mb=UINT32`` (default: ``0``) + This adds a Controller Memory Buffer of the given size at offset zero in BAR + 2. + +``legacy-cmb`` (default: ``off``) + By default, the device uses the "v1.4 scheme" for the Controller Memory + Buffer support (i.e, the CMB is initially disabled and must be explicitly + enabled by the host). Set this to ``on`` to behave as a v1.3 device wrt. the + CMB. + +Simple Copy +----------- + +The device includes support for TP 4065 ("Simple Copy Command"). A number of +additional ``nvme-ns`` device parameters may be used to control the Copy +command limits: + +``mssrl=UINT16`` (default: ``128``) + Set the Maximum Single Source Range Length (``MSSRL``). This is the maximum + number of logical blocks that may be specified in each source range. + +``mcl=UINT32`` (default: ``128``) + Set the Maximum Copy Length (``MCL``). This is the maximum number of logical + blocks that may be specified in a Copy command (the total for all source + ranges). + +``msrc=UINT8`` (default: ``127``) + Set the Maximum Source Range Count (``MSRC``). This is the maximum number of + source ranges that may be used in a Copy command. This is a 0's based value. + +Zoned Namespaces +---------------- + +A namespaces may be "Zoned" as defined by TP 4053 ("Zoned Namespaces"). Set +``zoned=on`` on an ``nvme-ns`` device to configure it as a zoned namespace. + +The namespace may be configured with additional parameters + +``zoned.zone_size=SIZE`` (default: ``128MiB``) + Define the zone size (``ZSZE``). + +``zoned.zone_capacity=SIZE`` (default: ``0``) + Define the zone capacity (``ZCAP``). If left at the default (``0``), the zone + capacity will equal the zone size. + +``zoned.descr_ext_size=UINT32`` (default: ``0``) + Set the Zone Descriptor Extension Size (``ZDES``). Must be a multiple of 64 + bytes. + +``zoned.cross_read=BOOL`` (default: ``off``) + Set to ``on`` to allow reads to cross zone boundaries. + +``zoned.max_active=UINT32`` (default: ``0``) + Set the maximum number of active resources (``MAR``). The default (``0``) + allows all zones to be active. + +``zoned.max_open=UINT32`` (default: ``0``) + Set the maximum number of open resources (``MOR``). The default (``0``) + allows all zones to be open. If ``zoned.max_active`` is specified, this value + must be less than or equal to that. + +Metadata +-------- + +The virtual namespace device supports LBA metadata in the form separate +metadata (``MPTR``-based) and extended LBAs. + +``ms=UINT16`` (default: ``0``) + Defines the number of metadata bytes per LBA. + +``mset=UINT8`` (default: ``0``) + Set to ``1`` to enable extended LBAs. + +End-to-End Data Protection +-------------------------- + +The virtual namespace device supports DIF- and DIX-based protection information +(depending on ``mset``). + +``pi=UINT8`` (default: ``0``) + Enable protection information of the specified type (type ``1``, ``2`` or + ``3``). + +``pil=UINT8`` (default: ``0``) + Controls the location of the protection information within the metadata. Set + to ``1`` to transfer protection information as the first eight bytes of + metadata. Otherwise, the protection information is transferred as the last + eight bytes. diff --git a/MAINTAINERS b/MAINTAINERS index 58f342108e9e..04beb34e7ec4 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -1974,7 +1974,7 @@ S: Supported F: hw/block/nvme* F: include/block/nvme.h F: tests/qtest/nvme-test.c -F: docs/specs/nvme.txt +F: docs/system/nvme.rst T: git git://git.infradead.org/qemu-nvme.git nvme-next megasas -- 2.31.1
