MFC r344955 (by imp):
Don't print all the I/O we abort on a reset, unless we're out of
retries.

When resetting the controller, we abort I/O. Prior to this fix, we
printed a ton of abort messages for I/O that we're going to
retry. This imparts no useful information. Stop printing them unless
our retry count is exhausted. Clarify code for when we don't retry,
and remove useless arg to a routine that's always called with it
as 'true'. All the other debug is still printed (including multiple
reset messages if we have multiple timeouts before the taskqueue
runs the actual reset) so that we know when we reset.

MFC r351352: Improve NVMe hot unplug handling.

If device is unplugged from the system (CSTS register reads return
0xffffffff), it makes no sense to send any more recovery requests or
expect any responses back. If there is a detach call in such state,
just stop all activity and free resources. If there is no detach
call (hot-plug is not supported), rely on normal timeout handling,
but when it trigger controller reset, do not wait for impossible and
quickly report failure.

Sponsored by: iXsystems, Inc.

MFC r330760: Add new opcodes and statuses from NVMe 1.3a.

MFC r344736 (by imp): Add ABORTED_BY_REQUEST to the list of things we look
at DNR bit and tell why to comment (code already does this)

MFC r344642 (by imp):
Unconditionally support unmapped BIOs. This was another shim for
supporting older kernels. However, all supported versions of FreeBSD
have unmapped I/Os (as do several that have gone EOL), remove it. It's
unlikely the driver would work on the older kernels anyway at this
point.

MFC r344640 (by imp):
Remove #ifdef code to support FreeBSD versions that haven't been
supported in years. A number of changes have been made to the driver
that likely wouldn't work on those older versions that aren't properly
ifdef'd and it's project policy to GC such code once it is stale.

MFC r337273 (by jhibbits):
nvme(4): Add bus_dmamap_sync() at the end of the request path

Summary:
Some architectures, in this case powerpc64, need explicit synchronization
barriers vs device accesses.

Prior to this change, when running 'make buildworld -j72' on a 18-core
(72-thread) POWER9, I would see controller resets often. With this change, I
don't see these resets messages, though another tester still does, for yet to be
determined reasons, so this may not be a complete fix. Additionally, I see a
~5-10% speed up in buildworld times, likely due to not needing to reset the
controller.

MFC r342546: Add descriptions to NVMe interrupts.

MFC r333127: Fix use-after-free in nvme_qpair_destroy().

dma_tag_payload should not be destroyed before payload_dma_map, and seems
it should be used there instead of dma_tag to match creation.

MFC r331046 (by imp): Try polling the qpairs on timeout.

On some systems, we're getting timeouts when we use multiple queues on
drives that work perfectly well on other systems. On a hunch, Jim
Harris suggested I poll the completion queue when we get a timeout.
This patch polls the completion queue if no fatal status was
indicated. If it had pending I/O, we complete that request and
return. Otherwise, if aborts are enabled and no fatal status, we abort
the command and return. Otherwise we reset the card.

This may clear up the problem, or we may see it result in lots of
timeouts and a performance problem. Either way, we'll know the next
step. We may also need to pay attention to the fatal status bit
of the controller.

Revert r330897:

This was intended to be a non-functional change. It wasn't. The commit
message was thus wrong. In addition it broke arm, and merged crypto
related code.

Revert with prejudice.

This revert skips files touched in r316370 since that commit was since
MFCed. This revert also skips files that require $FreeBSD$ property
changes.

Thank you to those who helped me get out of this mess including but not
limited to gonzo, kevans, rgrimes.

Requested by: gjb (re)

Partial merge of the SPDX changes

These changes are incomplete but are making it difficult
to determine what other changes can/should be merged.

No objections from: pfg

MFC r322997: Add CAM/NVMe support for CAM_DATA_SG

This adds support in pass(4) for data to be described with a
scatter-gather list (sglist) to augment the existing (single) virtual
address.

MFC r314889 (by imp):
Avoid dereferencing unintialized elements in the error path.

Some drives sometimes have errors for things like setting the number
of queue entries in the submission queue. The error paths taken for
these drives ensure a panic dereferencing uninialized data.

MFC r308431 (by scottl):
Convert the Q-Pair and PRP list memory allocations to use BUSDMA. Add a
bunch of safery belts and error handling in related codepaths.

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

nvme: do not pre-allocate MSI-X IRQ resources

The issue referenced here was resolved by other changes
in recent commits, so this code is no longer needed.

MFC after: 3 days
Sponsored by: Intel

nvme: use BUS_SPACE_MAXSIZE for bus_dma_tag_create maxsize parameter

This fixes i386 PAE build fallout from r281281.

Reported by: bz
MFC after: 1 week

nvme: remove CHATHAM related code

Chatham was an internal NVMe prototype board used for
early driver development.

MFC after: 1 week
Sponsored by: Intel

nvme: create separate DMA tag for non-payload DMA buffers

Submission and completion queue memory need to use a
separate DMA tag for mappings than payload buffers,
to ensure mappings remain contiguous even with DMAR
enabled.

Submitted by: kib
MFC after: 1 week
Sponsored by: Intel

nvme: Allocate all MSI resources up front so that we can fall back to
INTx if necessary.

Sponsored by: Intel
MFC after: 3 days

nvme: NVMe specification dictates 4-byte alignment for PRPs (not 8).

Sponsored by: Intel
MFC after: 3 days

Update copyright dates.

MFC after: 3 days

Remove remaining uio-related code.

The nvme_physio() function was removed quite a while ago, which was the
only user of this uio-related code.

Sponsored by: Intel
MFC after: 3 days

Fail any passthrough command whose transfer size exceeds the controller's
max transfer size. This guards against rogue commands coming in from
userspace.

Also add KASSERTS for the virtual address and unmapped bio cases, if the
transfer size exceeds the controller's max transfer size.

Sponsored by: Intel
MFC after: 3 days

Use MAXPHYS to specify the maximum I/O size for nvme(4).

Also allow admin commands to transfer up to this maximum I/O size, rather
than the artificial limit previously imposed. The larger I/O size is very
beneficial for upcoming firmware download support. This has the added
benefit of simplifying the code since both admin and I/O commands now use
the same maximum I/O size.

Sponsored by: Intel
MFC after: 3 days

Move the busdma mapping functions to nvme_qpair.c.

This removes nvme_uio.c completely.

Sponsored by: Intel

Do not panic when a busdma mapping operation fails.

Instead, print an error message and fail the associated command with
DATA_TRANSFER_ERROR NVMe completion status.

Sponsored by: Intel

Add unmapped bio support to nvme(4) and nvd(4).

Sponsored by: Intel

Add "type" to nvme_request, signifying if its payload is a VADDR, UIO, or
NULL. This simplifies decisions around if/how requests are routed through
busdma. It also paves the way for supporting unmapped bios.

Sponsored by: Intel

Fix printf format issue on i386.

Reported by: bz

Clean up debug prints.

1) Consistently use device_printf.
2) Make dump_completion and dump_command into something more
human-readable.

Sponsored by: Intel
Reviewed by: carl

Change a number of malloc(9) calls to use M_WAITOK instead of
M_NOWAIT.

Sponsored by: Intel
Suggested by: carl
Reviewed by: carl

Abort and do not retry any outstanding admin commands left over after
a controller reset.

Sponsored by: Intel
Reviewed by: carl

Add the ability to internally mark a controller as failed, if it is unable to
start or reset. Also add a notifier for NVMe consumers for controller fail
conditions and plumb this notifier for nvd(4) to destroy the associated
GEOM disks when a failure occurs.

This requires a bit of work to cover the races when a consumer is sending
I/O requests to a controller that is transitioning to the failed state. To
help cover this condition, add a task to defer completion of I/Os submitted
to a failed controller, so that the consumer will still always receive its
completions in a different context than the submission.

Sponsored by: Intel
Reviewed by: carl

Just disable the controller instead of deleting IO queues during detach.

This is just as effective, and removes the need for a bunch of admin commands
to a controller that's going to be disabled shortly anyways.

Sponsored by: Intel
Reviewed by: carl

Cap the number of retry attempts to a configurable number. This ensures
that if a specific I/O repeatedly times out, we don't retry it indefinitely.

The default number of retries will be 4, but is adjusted using hw.nvme.retry_count.

Sponsored by: Intel
Reviewed by: carl

Create struct nvme_status.

NVMe error log entries include status, so breaking this out into
its own data structure allows it to be included in both the
nvme_completion data structure as well as error log entry data
structures.

While here, expose nvme_completion_is_error(), and change all of
the places that were explicitly looking at sc/sct bits to use this
macro instead.

Sponsored by: Intel
Reviewed by: carl

Make nvme_ctrlr_reset a nop if a reset is already in progress.

This protects against cases where a controller crashes with multiple
I/O outstanding, each timing out and requesting controller resets
simultaneously.

While here, remove a debugging printf from a previous commit, and add
more logging around I/O that need to be resubmitted after a controller
reset.

Sponsored by: Intel
Reviewed by: carl

By default, always escalate to controller reset when an I/O times out.

While aborts are typically cleaner than a full controller reset, many times
an I/O timeout indicates other controller-level issues where aborts may not
work. NVMe drivers for other operating systems are also defaulting to
controller reset rather than aborts for timed out I/O.

Sponsored by: Intel
Reviewed by: carl

Add a tunable for the I/O timeout interval. Default is still 30 seconds,
but can be adjusted between a min/max of 5 and 120 seconds.

Sponsored by: Intel
Reviewed by: carl

Add handling for controller fatal status (csts.cfs).

On any I/O timeout, check for csts.cfs==1. If set, the controller
is reporting fatal status and we reset the controller immediately,
rather than trying to abort the timed out command.

This changeset also includes deferring the controller start portion
of the reset to a separate task. This ensures we are always performing
a controller start operation from a consistent context.

Sponsored by: Intel
Reviewed by: carl

Add controller reset capability to nvme(4) and ability to explicitly
invoke it from nvmecontrol(8).

Controller reset will be performed in cases where I/O are repeatedly
timing out, the controller reports an unrecoverable condition, or
when explicitly requested via IOCTL or an nvme consumer. Since the
controller may be in such a state where it cannot even process queue
deletion requests, we will perform a controller reset without trying
to clean up anything on the controller first.

Sponsored by: Intel
Reviewed by: carl

Keep a doubly-linked list of outstanding trackers.

This enables in-order re-submission of I/O after a controller reset.

Sponsored by: Intel

Enable asynchronous event requests on non-Chatham devices.

Also add logic to clean up all outstanding asynchronous event requests
when resetting or shutting down the controller, since these requests
will not be explicitly completed by the controller itself.

Sponsored by: Intel

Specify command timeout interval on a per-command type basis.

This is primarily driven by the need to disable timeouts for asynchronous
event requests, which by nature should not be timed out.

Sponsored by: Intel

Explicitly abort a timed out command, if the ABORT command sent to the
controller indicates the command was not found.

Sponsored by: Intel

Break out the code for completing an nvme_tracker object into a separate
function.

This allows for completions outside the normal completion path, for example
when an ABORT command fails due to the controller reporting the targeted
command does not exist. This is mainly for protection against a faulty
controller, but we need to clean up our internal request nonetheless.

Sponsored by: Intel

Add support for ABORT commands, including issuing these commands when
an I/O times out.

Also ensure that we retry commands that are aborted due to a timeout.

Sponsored by: Intel

Add an internal _nvme_qpair_submit_request function, which performs
the submit action assuming the qpair lock has already been acquired.

Also change nvme_qpair_submit_request to just lock/unlock the mutex
around a call to this new function.

This fixes a recursive mutex acquisition in the retry path.

Sponsored by: Intel

Use callout_reset_curcpu to allow the callout to be handled by the
current CPU and not always CPU 0.

This has the added benefit of reducing a huge amount of spinlock
contention on the callout_cpu spinlock for CPU 0.

Sponsored by: Intel

Fix build after r241659.

Add ability to queue nvme_request objects if no nvme_trackers are available.

This eliminates the need to manage queue depth at the nvd(4) level for
Chatham prototype board workarounds, and also adds the ability to
accept a number of requests on a single qpair that is much larger
than the number of trackers allocated.

Sponsored by: Intel

Preallocate a limited number of nvme_tracker objects per qpair, rather
than dynamically creating them at runtime.

Sponsored by: Intel

Create nvme_qpair_submit_request() which eliminates all of the code
duplication between the admin and io controller-level submit
functions.

Sponsored by: Intel

Simplify how the qpair lock is acquired and released.

Sponsored by: Intel

Cleanup uio-related code to use struct nvme_request and
nvme_ctrlr_submit_io_request().

While here, also fix case where a uio may have more than 1 iovec.
NVMe's definition of SGEs (called PRPs) only allows for the first SGE to
start on a non-page boundary. The simplest way to handle this is to
construct a temporary uio for each iovec, and submit an NVMe request
for each.

Sponsored by: Intel

Add nvme_ctrlr_submit_[admin|io]_request functions which consolidates
code for allocating nvme_tracker objects and making calls into
bus_dmamap_load for commands which have payloads.

Sponsored by: Intel

Add struct nvme_request object which contains all of the parameters passed
from an NVMe consumer.

This allows us to mostly build NVMe command buffers without holding the
qpair lock, and also allows for future queueing of nvme_request objects
in cases where the submission queue is full and no nvme_tracker objects
are available.

Sponsored by: Intel

Merge struct nvme_prp_list into struct nvme_tracker.

This simplifies the driver significantly where it is constructing
commands to be submitted to hardware. By reducing the number of
PRPs (NVMe parlance for SGE) from 128 to 32, it ensures we do not
allocate too much memory for more common smaller I/O sizes, while
still supporting up to 128KB I/O sizes.

This also paves the way for pre-allocation of nvme_tracker objects
for each queue which will simplify the I/O path even further.

Sponsored by: Intel

Add return codes to all functions used for submitting commands to I/O
queues.

Sponsored by: Intel

Count number of times each queue pair's interrupt handler is invoked.

Also add sysctls to query and reset each queue pair's stats, including
the new count added here.

Sponsored by: Intel

This is the first of several commits which will add NVM Express (NVMe)
support to FreeBSD. A full description of the overall functionality
being added is below. nvmexpress.org defines NVM Express as "an optimized
register interface, command set and feature set fo PCI Express (PCIe)-based
Solid-State Drives (SSDs)."

This commit adds nvme(4) and nvd(4) driver source code and Makefiles
to the tree.

Full NVMe functionality description:
Add nvme(4) and nvd(4) drivers and nvmecontrol(8) for NVM Express (NVMe)
device support.

There will continue to be ongoing work on NVM Express support, but there
is more than enough to allow for evaluation of pre-production NVM Express
devices as well as soliciting feedback. Questions and feedback are welcome.

nvme(4) implements NVMe hardware abstraction and is a provider of NVMe
namespaces. The closest equivalent of an NVMe namespace is a SCSI LUN.
nvd(4) is an NVMe consumer, surfacing NVMe namespaces as GEOM disks.
nvmecontrol(8) is used for NVMe configuration and management.

The following are currently supported:
nvme(4)
- full mandatory NVM command set support
- per-CPU IO queues (enabled by default but configurable)
- per-queue sysctls for statistics and full command/completion queue
dumps for debugging
- registration API for NVMe namespace consumers
- I/O error handling (except for timeoutsee below)
- compilation switches for support back to stable-7

nvd(4)
- BIO_DELETE and BIO_FLUSH (if supported by controller)
- proper BIO_ORDERED handling

nvmecontrol(8)
- devlist: list NVMe controllers and their namespaces
- identify: display controller or namespace identify data in
human-readable or hex format
- perftest: quick and dirty performance test to measure raw
performance of NVMe device without userspace/physio/GEOM
overhead

The following are still work in progress and will be completed over the
next 3-6 months in rough priority order:
- complete man pages
- firmware download and activation
- asynchronous error requests
- command timeout error handling
- controller resets
- nvmecontrol(8) log page retrieval

This has been primarily tested on amd64, with light testing on i386. I
would be happy to provide assistance to anyone interested in porting
this to other architectures, but am not currently planning to do this
work myself. Big-endian and dmamap sync for command/completion queues
are the main areas that would need to be addressed.

The nvme(4) driver currently has references to Chatham, which is an
Intel-developed prototype board which is not fully spec compliant.
These references will all be removed over time.

Sponsored by: Intel
Contributions from: Joe Golio/EMC <joseph dot golio at emc dot com>