[PATCH v5 0/6] cxl: Support device sanitation

[Davidlohr Bueso <dave@stgolabs.net>]

Hi,

Changes from v4 (https://lore.kernel.org/linux-cxl/20230421092321.12741-1-dave@stgolabs.net/):
    o Added patch 1 'security/state' sysfs file which will be the placeholder
      for userspace to know about pmem security or an on-going sanitation op.
    o Renamed some of the sanitation polling variables.
    o Picked up review tags for mock device test patches.

This adds the sanitation part of the background command handling. Some noteworthy items:

    o Treating Sanitation as such a special beast can make the code a bit invasive,
      but couldn't find a decent alternative. For example I realize that this is really
      ad-hoc code in __cxl_pci_mbox_send_cmd(). A lot of this also comes from the fact
      that polling for sanitize is supported, so sw still needs to keep up and serialize.
      
    o Nothing depends explicitly on CPU cacheline management

    o All sysfs files/attributes in the security directory are visible.

    o Continue to use __ATTR() macros for sysfs attributes instead of the requested
      DEVICE_ATTR_*() ones because of the naming the security directory, otherwise
      names don't match.

Patch 1 adds a new security/state file.
Patch 2 paves the required sanitation handling code before actually using it.
Patch 3,4 wires up sanitation + unit test.
Patch 5,6 wires up secure erase + unit test.

Testing.
========

o There are the mock device tests for Sanitize and Secure Erase.

o The latest (v2) qemu bg/sanitize support series is posted here:
	https://lore.kernel.org/linux-cxl/20230418172337.19207-1-dave@stgolabs.net/

(1) Window where driver is out of sync with hw (Sanitation async polling).

[root@fedora ~]# echo 1 > /sys/bus/cxl/devices/mem0/security/sanitize
[  159.297482] cxl_pci:__cxl_pci_mbox_send_cmd:243: cxl_pci 0000:37:00.0: Sending command: 0x4400
[  159.298648] cxl_pci:cxl_pci_mbox_wait_for_doorbell:73: cxl_pci 0000:37:00.0: Doorbell wait took 0ms
[  159.299908] cxl_pci:__cxl_pci_mbox_send_cmd:295: cxl_pci 0000:37:00.0: Sanitation operation started
>>>> qemu informs sanitation is done <<<<<
[root@fedora ~]# echo 1 > /sys/bus/cxl/devices/mem0/security/sanitize
[  165.897345] cxl_pci 0000:37:00.0: Failed to sanitize device : -16
[  171.692050] cxl_pci:cxl_mbox_sanitize_work:147: cxl_pci 0000:37:00.0: Sanitation operation ended
[root@fedora ~]# echo 1 > /sys/bus/cxl/devices/mem0/security/sanitize
[  173.373337] cxl_pci:__cxl_pci_mbox_send_cmd:243: cxl_pci 0000:37:00.0: Sending command: 0x4400
[  173.374498] cxl_pci:cxl_pci_mbox_wait_for_doorbell:73: cxl_pci 0000:37:00.0: Doorbell wait took 0ms
[  173.375727] cxl_pci:__cxl_pci_mbox_send_cmd:295: cxl_pci 0000:37:00.0: Sanitation operation started

(2) Perform sanitation of more than one memdev at a time (Sanitation async polling).

[root@fedora ~]# echo 1 > /sys/bus/cxl/devices/mem1/security/sanitize
[  351.287129] cxl_pci:__cxl_pci_mbox_send_cmd:243: cxl_pci 0000:36:00.0: Sending command: 0x4400
[  351.288403] cxl_pci:cxl_pci_mbox_wait_for_doorbell:73: cxl_pci 0000:36:00.0: Doorbell wait took 0ms
[  351.289706] cxl_pci:__cxl_pci_mbox_send_cmd:295: cxl_pci 0000:36:00.0: Sanitation operation started
[root@fedora ~]# echo 1 > /sys/bus/cxl/devices/mem0/security/sanitize
[  353.058614] cxl_pci:__cxl_pci_mbox_send_cmd:243: cxl_pci 0000:37:00.0: Sending command: 0x4400
[  353.059854] cxl_pci:cxl_pci_mbox_wait_for_doorbell:73: cxl_pci 0000:37:00.0: Doorbell wait took 0ms
[  353.061126] cxl_pci:__cxl_pci_mbox_send_cmd:295: cxl_pci 0000:37:00.0: Sanitation operation started
>>>>  qemu informs sanitation is done <<<<<
>>>>  qemu informs sanitation is done <<<<<
[  363.692138] cxl_pci:cxl_mbox_sanitize_work:147: cxl_pci 0000:36:00.0: Sanitation operation ended
[  365.227416] cxl_pci:cxl_mbox_sanitize_work:147: cxl_pci 0000:37:00.0: Sanitation operation ended

(3) Perform sanitation of more than one memdev at a time (Sanitation async irq).

[root@fedora ~]# echo 1 > /sys/bus/cxl/devices/mem1/security/sanitize
[  193.729821] cxl_pci:__cxl_pci_mbox_send_cmd:243: cxl_pci 0000:c1:00.0: Sending command: 0x4400
[  193.731071] cxl_pci:cxl_pci_mbox_wait_for_doorbell:73: cxl_pci 0000:c1:00.0: Doorbell wait took 0ms
[  193.732360] cxl_pci:__cxl_pci_mbox_send_cmd:295: cxl_pci 0000:c1:00.0: Sanitation operation started
[root@fedora ~]# echo 1 > /sys/bus/cxl/devices/mem0/security/sanitize
[  197.001466] cxl_pci:__cxl_pci_mbox_send_cmd:243: cxl_pci 0000:36:00.0: Sending command: 0x4400
[  197.002694] cxl_pci:cxl_pci_mbox_wait_for_doorbell:73: cxl_pci 0000:36:00.0: Doorbell wait took 0ms
[  197.003956] cxl_pci:__cxl_pci_mbox_send_cmd:295: cxl_pci 0000:36:00.0: Sanitation operation started
>>>> qemu says sanitation is done <<<<
[  197.731473] cxl_pci:cxl_pci_mbox_irq:119: cxl_pci 0000:c1:00.0: Sanitation operation ended
>>>> qemu says sanitation is done <<<<
[  201.003258] cxl_pci:cxl_pci_mbox_irq:119: cxl_pci 0000:36:00.0: Sanitation operation ended

(4) Forbid new sanitation while one is in progress (Sanitation async irq).
 
[root@fedora ~]# cat /sys/bus/cxl/devices/mem0/security/state
disabled
[root@fedora ~]# echo 1 > /sys/bus/cxl/devices/mem0/security/sanitize
[   39.284258] cxl_pci:__cxl_pci_mbox_send_cmd:243: cxl_pci 0000:36:00.0: Sending command: 0x4400
[   39.285459] cxl_pci:cxl_pci_mbox_wait_for_doorbell:73: cxl_pci 0000:36:00.0: Doorbell wait took 0ms
[   39.286723] cxl_pci:__cxl_pci_mbox_send_cmd:295: cxl_pci 0000:36:00.0: Sanitation operation started
[root@fedora ~]# cat /sys/bus/cxl/devices/mem0/security/state
sanitize
[root@fedora ~]# echo 1 > /sys/bus/cxl/devices/mem0/security/sanitize
[   42.697129] cxl_pci:__cxl_pci_mbox_send_cmd:243: cxl_pci 0000:36:00.0: Sending command: 0x4400
[   42.698323] cxl_pci:cxl_pci_mbox_wait_for_doorbell:73: cxl_pci 0000:36:00.0: Doorbell wait took 0ms
[   42.699525] cxl_pci:__cxl_pci_mbox_send_cmd:335: cxl_pci 0000:36:00.0: Mailbox operation had an error: ongoing background operation
[   42.701119] cxl_pci 0000:36:00.0: Failed to sanitize device : -6
>>>> qemu says sanitation is done <<<<
[   43.285334] cxl_pci:cxl_pci_mbox_irq:119: cxl_pci 0000:36:00.0: Sanitation operation ended


Applies against 'for-6.5/cxl-background' from cxl.git.

Please consider for v6.5.

Thanks!

Davidlohr Bueso (6):
  cxl/mem: Introduce security state sysfs file
  cxl/mbox: Add sanitation handling machinery
  cxl/mem: Wire up Sanitation support
  cxl/test: Add Sanitize opcode support
  cxl/mem: Support Secure Erase
  cxl/test: Add Secure Erase opcode support

 Documentation/ABI/testing/sysfs-bus-cxl |  37 +++++++
 drivers/cxl/core/mbox.c                 |  59 ++++++++++
 drivers/cxl/core/memdev.c               | 139 ++++++++++++++++++++++++
 drivers/cxl/cxlmem.h                    |  26 +++++
 drivers/cxl/pci.c                       |  88 ++++++++++++++-
 drivers/cxl/security.c                  |   3 +
 tools/testing/cxl/test/mem.c            |  52 +++++++++
 7 files changed, 400 insertions(+), 4 deletions(-)

--
2.40.1