kernel/linux.git/drivers/cxl/core/memdev.c, branch v6.6.132

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

2024-07-05T07:34:06+00:00

[ Upstream commit b98d042698a32518c93e47730e9ad86b387a9c21 ] 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 Stable-dep-of: 285f2a088414 ("cxl/region: Avoid null pointer dereference in region lookup") Signed-off-by: Sasha Levin

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

2024-01-10T16:17:02+00:00

commit 0e33ac9c3ffe5e4f55c68345f44cea7fec2fe750 upstream. 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 Signed-off-by: Greg Kroah-Hartman

cxl/core: Always hold region_rwsem while reading poison lists

2024-01-10T16:16:58+00:00

[ Upstream commit 5558b92e8d39e18aa19619be2ee37274e9592528 ] 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 Signed-off-by: Sasha Levin

cxl: Add cxl_decoders_committed() helper

2024-01-10T16:16:58+00:00

[ Upstream commit 458ba8189cb4380aa6a6cc4d52ab067f80a64829 ] 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 Stable-dep-of: 5558b92e8d39 ("cxl/core: Always hold region_rwsem while reading poison lists") Signed-off-by: Sasha Levin

cxl/mem: Fix shutdown order

2023-11-20T10:59:30+00:00

[ Upstream commit 88d3917f82ed4215a2154432c26de1480a61b209 ] 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 Signed-off-by: Sasha Levin

cxl/memdev: Fix sanitize vs decoder setup locking

2023-11-20T10:59:30+00:00

[ Upstream commit 339818380868e34ff2c482db05031bf47a67d609 ] 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 Signed-off-by: Sasha Levin

cxl/pci: Fix sanitize notifier setup

2023-11-20T10:59:30+00:00

[ Upstream commit 5f2da19714465739da2449253b13ac06cb353a26 ] Fix a race condition between the mailbox-background command interrupt firing and the security-state sysfs attribute being removed. The race is difficult to see due to the awkward placement of the sanitize-notifier setup code and the multiple places the teardown calls are made, cxl_memdev_security_init() and cxl_memdev_security_shutdown(). Unify setup in one place, cxl_sanitize_setup_notifier(). Arrange for the paired cxl_sanitize_teardown_notifier() to safely quiet the notifier and let the cxl_memdev + irq be unregistered later in the flow. Note: The special wrinkle of the sanitize notifier is that it interacts with interrupts, which are enabled early in the flow, and it interacts with memdev sysfs which is not initialized until late in the flow. Hence why this setup routine takes an @cxlmd argument, and not just @mds. This fix is also needed as a preparation fix for a memdev unregistration crash. Reported-by: Jonathan Cameron Closes: http://lore.kernel.org/r/20230929100316.00004546@Huawei.com Cc: Dave Jiang Cc: Davidlohr Bueso Fixes: 0c36b6ad436a ("cxl/mbox: Add sanitization handling machinery") Reviewed-by: Dave Jiang Reviewed-by: Ira Weiny Reviewed-by: Davidlohr Bueso Reviewed-by: Jonathan Cameron Signed-off-by: Dan Williams Signed-off-by: Sasha Levin

cxl/pci: Clarify devm host for memdev relative setup

2023-11-20T10:59:30+00:00

[ Upstream commit f29a824b0b6710328a78b018de3c2cfa9db65876 ] It is all too easy to get confused about @dev usage in the CXL driver stack. Before adding a new cxl_pci_probe() setup operation that has a devm lifetime dependent on @cxlds->dev binding, but also references @cxlmd->dev, and prints messages, rework the devm_cxl_add_memdev() and cxl_memdev_setup_fw_upload() function signatures to make this distinction explicit. I.e. pass in the devm context as an @host argument rather than infer it from other objects. This is in preparation for adding a devm_cxl_sanitize_setup_notifier(). Note the whitespace fixup near the change of the devm_cxl_add_memdev() signature. That uncaught typo originated in the patch that added cxl_memdev_security_init(). Reviewed-by: Jonathan Cameron Reviewed-by: Ira Weiny Reviewed-by: Dave Jiang Signed-off-by: Dan Williams Stable-dep-of: 5f2da1971446 ("cxl/pci: Fix sanitize notifier setup") Signed-off-by: Sasha Levin

cxl/pci: Remove inconsistent usage of dev_err_probe()

2023-11-20T10:59:30+00:00

[ Upstream commit 2627c995c15dc375f4b5a591d782a14b1c0e3e7d ] If dev_err_probe() is to be used it should at least be used consistently within the same function. It is also worth questioning whether every potential -ENOMEM needs an explicit error message. Remove the cxl_setup_fw_upload() error prints for what are rare / hardware-independent failures. Reviewed-by: Jonathan Cameron Reviewed-by: Ira Weiny Reviewed-by: Davidlohr Bueso Reviewed-by: Dave Jiang Signed-off-by: Dan Williams Stable-dep-of: 5f2da1971446 ("cxl/pci: Fix sanitize notifier setup") Signed-off-by: Sasha Levin

cxl/pci: Cleanup 'sanitize' to always poll

2023-11-20T10:59:30+00:00

[ Upstream commit e30a106558e7d1e06d1fcfd12466dc646673d03d ] In preparation for fixing the init/teardown of the 'sanitize' workqueue and sysfs notification mechanism, arrange for cxl_mbox_sanitize_work() to be the single location where the sysfs attribute is notified. With that change there is no distinction between polled mode and interrupt mode. All the interrupt does is accelerate the polling interval. The change to check for "mds->security.sanitize_node" under the lock is there to ensure that the interrupt, the work routine and the setup/teardown code can all have a consistent view of the registered notifier and the workqueue state. I.e. the expectation is that the interrupt is live past the point that the sanitize sysfs attribute is published, and it may race teardown, so it must be consulted under a lock. Given that new locking requirement, cxl_pci_mbox_irq() is moved from hard to thread irq context. Lastly, some opportunistic replacements of "queue_delayed_work(system_wq, ...)", which is just open coded schedule_delayed_work(), are included. Reviewed-by: Dave Jiang Reviewed-by: Jonathan Cameron Reviewed-by: Ira Weiny Reviewed-by: Davidlohr Bueso Signed-off-by: Dan Williams Stable-dep-of: 5f2da1971446 ("cxl/pci: Fix sanitize notifier setup") Signed-off-by: Sasha Levin