net/smc: change the term virtual ISM to Emulated-ISM

According to latest release of SMCv2.1[1], the term 'virtual ISM' has
been changed to 'Emulated-ISM' to avoid the ambiguity of the word
'virtual' in different contexts. So the names or comments in the code
need be modified accordingly.

[1] https://www.ibm.com/support/pages/node/7112343

Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
Link: https://lore.kernel.org/r/20240205033317.127269-1-guwen@linux.alibaba.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/smc: manage system EID in SMC stack instead of ISM driver

The System EID (SEID) is an internal EID that is used by the SMCv2
software stack that has a predefined and constant value representing
the s390 physical machine that the OS is executing on. So it should
be managed by SMC stack instead of ISM driver and be consistent for
all ISMv2 device (including virtual ISM devices) on s390 architecture.

Suggested-by: Alexandra Winter <wintera@linux.ibm.com>
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Reviewed-and-tested-by: Wenjia Zhang <wenjia@linux.ibm.com>
Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: compatible with 128-bits extended GID of virtual ISM device

According to virtual ISM support feature defined by SMCv2.1, GIDs of
virtual ISM device are UUIDs defined by RFC4122, which are 128-bits
long. So some adaptation work is required. And note that the GIDs of
existing platform firmware ISM devices still remain 64-bits long.

Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: define a reserved CHID range for virtual ISM devices

According to virtual ISM support feature defined by SMCv2.1, CHIDs in
the range 0xFF00 to 0xFFFF are reserved for use by virtual ISM devices.

And two helpers are introduced to distinguish virtual ISM devices from
the existing platform firmware ISM devices.

Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Reviewed-and-tested-by: Wenjia Zhang <wenjia@linux.ibm.com>
Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: Register SMC-D as ISM client

Register the smc module with the new ism device driver API.
This is the second part of a bigger overhaul of the interfaces between SMC
and ISM.

Signed-off-by: Stefan Raspl <raspl@linux.ibm.com>
Signed-off-by: Jan Karcher <jaka@linux.ibm.com>
Signed-off-by: Wenjia Zhang <wenjia@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: Eliminate struct smc_ism_position

This struct is used in a single place only, and its usage generates
inefficient code. Time to clean up!

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-and-tested-by: Stefan Raspl <raspl@linux.ibm.com>
Signed-off-by: Wenjia Zhang < wenjia@linux.ibm.com>
Reviewed-by: Tony Lu <tonylu@linux.alibaba.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: keep static copy of system EID

The system EID is retrieved using an registered ISM device each time
when needed. This adds some unnecessary complexity at all places where
the system EID is needed, but no ISM device is at hand.
Simplify the code and save the system EID in a static variable in
smc_ism.c.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Guvenc Gulce <guvenc@linux.ibm.com>
Signed-off-by: Guvenc Gulce <guvenc@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: Add support for obtaining SMCD device list

Deliver SMCD device information via netlink based
diagnostic interface.

Signed-off-by: Guvenc Gulce <guvenc@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/smc: Refactor smc ism v2 capability handling

Encapsulate the smc ism v2 capability boolean value
in a function for better information hiding.

Signed-off-by: Guvenc Gulce <guvenc@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/smc: introduce CHID callback for ISM devices

With SMCD version 2 the CHIDs of ISM devices are needed for the
CLC handshake.
This patch provides the new callback to retrieve the CHID of an
ISM device.

Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: introduce System Enterprise ID (SEID)

SMCD version 2 defines a System Enterprise ID (short SEID).
This patch contains the SEID creation and adds the callback to
retrieve the created SEID.

Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: switch smcd_dev_list spinlock to mutex

The similar smc_ib_devices spinlock has been converted to a mutex.
Protecting the smcd_dev_list by a mutex is possible as well. This
patch converts the smcd_dev_list spinlock to a mutex.

Fixes: c6ba7c9ba43d ("net/smc: add base infrastructure for SMC-D and ISM")
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: add SMC-D shutdown signal

When a SMC-D link group is freed, a shutdown signal should be sent to
the peer to indicate that the link group is invalid. This patch adds the
shutdown signal to the SMC code.

Signed-off-by: Hans Wippel <hwippel@linux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc: add base infrastructure for SMC-D and ISM

SMC supports two variants: SMC-R and SMC-D. For data transport, SMC-R
uses RDMA devices, SMC-D uses so-called Internal Shared Memory (ISM)
devices. An ISM device only allows shared memory communication between
SMC instances on the same machine. For example, this allows virtual
machines on the same host to communicate via SMC without RDMA devices.

This patch adds the base infrastructure for SMC-D and ISM devices to
the existing SMC code. It contains the following:

* ISM driver interface:
This interface allows an ISM driver to register ISM devices in SMC. In
the process, the driver provides a set of device ops for each device.
SMC uses these ops to execute SMC specific operations on or transfer
data over the device.

* Core SMC-D link group, connection, and buffer support:
Link groups, SMC connections and SMC buffers (in smc_core) are
extended to support SMC-D.

* SMC type checks:
Some type checks are added to prevent using SMC-R specific code for
SMC-D and vice versa.

To actually use SMC-D, additional changes to pnetid, CLC, CDC, etc. are
required. These are added in follow-up patches.

Signed-off-by: Hans Wippel <hwippel@linux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Suggested-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>