kernel/linux.git/drivers/cxl/core/memdev.c, branch v6.12.80

cxl: Convert cxl_internal_send_cmd() to use 'struct cxl_mailbox' as input

2024-09-12T15:39:10+00:00

With the CXL mailbox context split out, cxl_internal_send_cmd() can take 'struct cxl_mailbox' as an input parameter rather than 'struct memdev_dev_state'. Change input parameter for cxl_internal_send_cmd() and fixup all impacted call sites. Reviewed-by: Fan Ni Reviewed-by: Jonathan Cameron Reviewed-by: Alison Schofield Reviewed-by: Ira Weiny Link: https://patch.msgid.link/20240905223711.1990186-4-dave.jiang@intel.com Signed-off-by: Dave Jiang

cxl: Move mailbox related bits to the same context

2024-09-12T15:38:01+00:00

Create a new 'struct cxl_mailbox' and move all mailbox related bits to it. This allows isolation of all CXL mailbox data in order to export some of the calls to external kernel callers and avoid exporting of CXL driver specific bits such has device states. The allocation of 'struct cxl_mailbox' is also split out with cxl_mailbox_init() so the mailbox can be created independently. Reviewed-by: Jonathan Cameron Reviewed-by: Alejandro Lucero Reviewed-by: Fan Ni Reviewed-by: Alison Schofield Reviewed-by: Ira Weiny Link: https://patch.msgid.link/20240905223711.1990186-3-dave.jiang@intel.com Signed-off-by: Dave Jiang

cxl/region: Move cxl_dpa_to_region() work to the region driver

2024-04-30T19:24:42+00:00

This helper belongs in the region driver as it is only useful with CONFIG_CXL_REGION. Add a stub in core.h for when the region driver is not built. Signed-off-by: Alison Schofield Reviewed-by: Jonathan Cameron Reviewed-by: Ira Weiny Link: https://lore.kernel.org/r/05e30f788d62b3dd398aff2d2ea50a6aaa7c3313.1714496730.git.alison.schofield@intel.com Signed-off-by: Dave Jiang

cxl: Fix sysfs export of qos_class for memdev

2024-02-17T07:20:34+00:00

Current implementation exports only to /sys/bus/cxl/devices/.../memN/qos_class. With both ram and pmem exposed, the second registered sysfs attribute is rejected as duplicate. It's not possible to create qos_class under the dev_groups via the driver due to the ram and pmem sysfs sub-directories already created by the device sysfs groups. Move the ram and pmem qos_class to the device sysfs groups and add a call to sysfs_update() after the perf data are validated so the qos_class can be visible. The end results should be /sys/bus/cxl/devices/.../memN/ram/qos_class and /sys/bus/cxl/devices/.../memN/pmem/qos_class. Signed-off-by: Dave Jiang Link: https://lore.kernel.org/r/20240206190431.1810289-4-dave.jiang@intel.com Reviewed-by: Jonathan Cameron Signed-off-by: Dan Williams

cxl/core: use sysfs_emit() for attr's _show()

2024-01-12T22:47:04+00:00

sprintf() is deprecated for sysfs, use preferred sysfs_emit() instead. Signed-off-by: Shiyang Ruan Reviewed-by: Jonathan Cameron Reviewed-by: Dave Jiang Reviewed-by: Fan Ni Link: https://lore.kernel.org/r/20240112062709.2490947-1-ruansy.fnst@fujitsu.com Signed-off-by: Dan Williams

cxl/memdev: Hold region_rwsem during inject and clear poison ops

2023-11-30T01:23:03+00:00

Poison inject and clear are supported via debugfs where a privileged user can inject and clear poison to a device physical address. Commit 458ba8189cb4 ("cxl: Add cxl_decoders_committed() helper") added a lockdep assert that highlighted a gap in poison inject and clear functions where holding the dpa_rwsem does not assure that a a DPA is not added to a region. The impact for inject and clear is that if the DPA address being injected or cleared has been attached to a region, but not yet committed, the dev_dbg() message intended to alert the debug user that they are acting on a mapped address is not emitted. Also, the cxl_poison trace event that serves as a log of the inject and clear activity will not include region info. Close this gap by snapshotting an unchangeable region state during poison inject and clear operations. That means holding both the region_rwsem and the dpa_rwsem during the inject and clear ops. Fixes: d2fbc4865802 ("cxl/memdev: Add support for the Inject Poison mailbox command") Fixes: 9690b07748d1 ("cxl/memdev: Add support for the Clear Poison mailbox command") Signed-off-by: Alison Schofield Reviewed-by: Davidlohr Bueso Reviewed-by: Dave Jiang Link: https://lore.kernel.org/r/08721dc1df0a51e4e38fecd02425c3475912dfd5.1701041440.git.alison.schofield@intel.com Signed-off-by: Dan Williams

cxl/core: Always hold region_rwsem while reading poison lists

2023-11-30T01:03:53+00:00

A read of a device poison list is triggered via a sysfs attribute and the results are logged as kernel trace events of type cxl_poison. The work is managed by either: a) the region driver when one of more regions map the device, or by b) the memdev driver when no regions map the device. In the case of a) the region driver holds the region_rwsem while reading the poison by committed endpoint decoder mappings and for any unmapped resources. This makes sure that the cxl_poison trace event trace reports valid region info. (Region name, HPA, and UUID). In the case of b) the memdev driver holds the dpa_rwsem preventing new DPA resources from being attached to a region. However, it leaves a gap between region attach and decoder commit actions. If a DPA in the gap is in the poison list, the cxl_poison trace event will omit the region info. Close the gap by holding the region_rwsem and the dpa_rwsem when reading poison per memdev. Since both methods now hold both locks, down_read both from the caller. Doing so also addresses the lockdep assert that found this issue: Commit 458ba8189cb4 ("cxl: Add cxl_decoders_committed() helper") Fixes: f0832a586396 ("cxl/region: Provide region info to the cxl_poison trace event") Signed-off-by: Alison Schofield Reviewed-by: Davidlohr Bueso Reviewed-by: Dave Jiang Link: https://lore.kernel.org/r/08e8e7ec9a3413b91d51de39e385653494b1eed0.1701041440.git.alison.schofield@intel.com Signed-off-by: Dan Williams

cxl: Add cxl_decoders_committed() helper

2023-10-28T03:29:41+00:00

Add a helper to retrieve the number of decoders committed for the port. Replace all the open coding of the calculation with the helper. Link: https://lore.kernel.org/linux-cxl/651c98472dfed_ae7e729495@dwillia2-xfh.jf.intel.com.notmuch/ Suggested-by: Dan Williams Signed-off-by: Dave Jiang Reviewed-by: Jonathan Cameron Reviewed-by: Jim Harris Reviewed-by: Alison Schofield Link: https://lore.kernel.org/r/169747906849.272156.1729290904857372335.stgit@djiang5-mobl3 Signed-off-by: Dan Williams

cxl/mem: Fix shutdown order

2023-10-09T18:35:45+00:00

Ira reports that removing cxl_mock_mem causes a crash with the following trace: BUG: kernel NULL pointer dereference, address: 0000000000000044 [..] RIP: 0010:cxl_region_decode_reset+0x7f/0x180 [cxl_core] [..] Call Trace: cxl_region_detach+0xe8/0x210 [cxl_core] cxl_decoder_kill_region+0x27/0x40 [cxl_core] cxld_unregister+0x29/0x40 [cxl_core] devres_release_all+0xb8/0x110 device_unbind_cleanup+0xe/0x70 device_release_driver_internal+0x1d2/0x210 bus_remove_device+0xd7/0x150 device_del+0x155/0x3e0 device_unregister+0x13/0x60 devm_release_action+0x4d/0x90 ? __pfx_unregister_port+0x10/0x10 [cxl_core] delete_endpoint+0x121/0x130 [cxl_core] devres_release_all+0xb8/0x110 device_unbind_cleanup+0xe/0x70 device_release_driver_internal+0x1d2/0x210 bus_remove_device+0xd7/0x150 device_del+0x155/0x3e0 ? lock_release+0x142/0x290 cdev_device_del+0x15/0x50 cxl_memdev_unregister+0x54/0x70 [cxl_core] This crash is due to the clearing out the cxl_memdev's driver context (@cxlds) before the subsystem is done with it. This is ultimately due to the region(s), that this memdev is a member, being torn down and expecting to be able to de-reference @cxlds, like here: static int cxl_region_decode_reset(struct cxl_region *cxlr, int count) ... if (cxlds->rcd) goto endpoint_reset; ... Fix it by keeping the driver context valid until memdev-device unregistration, and subsequently the entire stack of related dependencies, unwinds. Fixes: 9cc238c7a526 ("cxl/pci: Introduce cdevm_file_operations") Reported-by: Ira Weiny Reviewed-by: Davidlohr Bueso Reviewed-by: Dave Jiang Reviewed-by: Jonathan Cameron Reviewed-by: Ira Weiny Tested-by: Ira Weiny Signed-off-by: Dan Williams

cxl/memdev: Fix sanitize vs decoder setup locking

2023-10-06T07:12:45+00:00

The sanitize operation is destructive and the expectation is that the device is unmapped while in progress. The current implementation does a lockless check for decoders being active, but then does nothing to prevent decoders from racing to be committed. Introduce state tracking to resolve this race. This incidentally cleans up unpriveleged userspace from triggering mmio read cycles by spinning on reading the 'security/state' attribute. Which at a minimum is a waste since the kernel state machine can cache the completion result. Lastly cxl_mem_sanitize() was mistakenly marked EXPORT_SYMBOL() in the original implementation, but an export was never required. Fixes: 0c36b6ad436a ("cxl/mbox: Add sanitization handling machinery") Cc: Davidlohr Bueso Reviewed-by: Jonathan Cameron Reviewed-by: Davidlohr Bueso Reviewed-by: Dave Jiang Signed-off-by: Dan Williams