- 31 Oct, 2023 3 commits
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Dan Williams authored
Pickup some misc. CXL updates for v6.7.
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Dan Williams authored
Merge some prep-work for CXL QOS class support. This cycle saw large collisions with mm on this topic, so the bulk of this topic needs to wait.
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Dan Williams authored
Restricted CXL Host (RCH) Error Handling undoes the topology munging of CXL 1.1 to enabled some AER recovery, and lands some base infrastructure for handling Root-Complex-Event-Collectors (RCECs) with CXL. Include this long running series finally for v6.7.
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- 28 Oct, 2023 23 commits
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Dave Jiang authored
Some of the routines in ACPI driver/acpi/tables.c can be shared with parsing CDAT. CDAT is a device-provided data structure that is formatted similar to a platform provided ACPI table. CDAT is used by CXL and can exist on platforms that do not use ACPI. Split out the common routine from ACPI to accommodate platforms that do not support ACPI and move that to /lib. The common routines can be built outside of ACPI if FIRMWARE_TABLES is selected. Link: https://lore.kernel.org/linux-cxl/CAJZ5v0jipbtTNnsA0-o5ozOk8ZgWnOg34m34a9pPenTyRLj=6A@mail.gmail.com/Suggested-by:
"Rafael J. Wysocki" <rafael@kernel.org> Reviewed-by:
Hanjun Guo <guohanjun@huawei.com> Reviewed-by:
Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by:
Dave Jiang <dave.jiang@intel.com> Acked-by:
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Link: https://lore.kernel.org/r/169713683430.2205276.17899451119920103445.stgit@djiang5-mobl3Signed-off-by:
Dan Williams <dan.j.williams@intel.com>
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Dave Jiang authored
Add read_cdat_data() call in cxl_switch_port_probe() to allow reading of CDAT data for CXL switches. read_cdat_data() needs to be adjusted for the retrieving of the PCIe device depending on if the passed in port is endpoint or switch. Reviewed-by:
Davidlohr Bueso <dave@stgolabs.net> Reviewed-by:
Ira Weiny <ira.weiny@intel.com> Reviewed-by:
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Dave Jiang authored
A CDAT table is available from a CXL device. The table is read by the driver and cached in software. With the CXL subsystem needing to parse the CDAT table, the checksum should be verified. Add checksum verification after the CDAT table is read from device. Reviewed-by:
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Dave Jiang authored
Export the QoS Throttling Group ID from the CXL Fixed Memory Window Structure (CFMWS) under the root decoder sysfs attributes as qos_class. CXL rev3.0 9.17.1.3 CXL Fixed Memory Window Structure (CFMWS) cxl cli will use this id to match with the _DSM retrieved id for a hot-plugged CXL memory device DPA memory range to make sure that the DPA range is under the right CFMWS window. Reviewed-by:
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Robert Richter authored
struct cxl_register_map carries a @dev parameter for devm operations. Simplify the function interface to use that instead of a separate @dev argument. Signed-off-by:
Terry Bowman <terry.bowman@amd.com> Signed-off-by:
Robert Richter <rrichter@amd.com> Reviewed-by:
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Robert Richter authored
Trivial change that renames variable phys_addr in cxl_map_component_regs() to shorten its length to keep the 80 char size limit for the line and also for consistency between the different paths. Signed-off-by:
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Robert Richter authored
AER corrected and uncorrectable internal errors (CIE/UIE) are masked in their corresponding mask registers per default once in power-up state. [1][2] Enable internal errors for RCECs to receive CXL downstream port errors of Restricted CXL Hosts (RCHs). [1] CXL 3.0 Spec, 12.2.1.1 - RCH Downstream Port Detected Errors [2] PCIe Base Spec r6.0, 7.8.4.3 Uncorrectable Error Mask Register, 7.8.4.6 Correctable Error Mask Register Co-developed-by:Bjorn Helgaas <bhelgaas@google.com> Reviewed-by:
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Robert Richter authored
In Restricted CXL Device (RCD) mode a CXL device is exposed as an RCiEP, but CXL downstream and upstream ports are not enumerated and not visible in the PCIe hierarchy. [1] Protocol and link errors from these non-enumerated ports are signaled as internal AER errors, either Uncorrectable Internal Error (UIE) or Corrected Internal Errors (CIE) via an RCEC. Restricted CXL host (RCH) downstream port-detected errors have the Requester ID of the RCEC set in the RCEC's AER Error Source ID register. A CXL handler must then inspect the error status in various CXL registers residing in the dport's component register space (CXL RAS capability) or the dport's RCRB (PCIe AER extended capability). [2] Errors showing up in the RCEC's error handler must be handled and connected to the CXL subsystem. Implement this by forwarding the error to all CXL devices below the RCEC. Since the entire CXL device is controlled only using PCIe Configuration Space of device 0, function 0, only pass it there [3]. The error handling is limited to currently supported devices with the Memory Device class code set (CXL Type 3 Device, PCI_CLASS_MEMORY_CXL, 502h), handle downstream port errors in the device's cxl_pci driver. Support for other CXL Device Types (e.g. a CXL.cache Device) can be added later. To handle downstream port errors in addition to errors directed to the CXL endpoint device, a handler must also inspect the CXL RAS and PCIe AER capabilities of the CXL downstream port the device is connected to. Since CXL downstream port errors are signaled using internal errors, the handler requires those errors to be unmasked. This is subject of a follow-on patch. The reason for choosing this implementation is that the AER service driver claims the RCEC device, but does not allow it to register a custom specific handler to support CXL. Connecting the RCEC hard-wired with a CXL handler does not work, as the CXL subsystem might not be present all the time. The alternative to add an implementation to the portdrv to allow the registration of a custom RCEC error handler isn't worth doing it as CXL would be its only user. Instead, just check for an CXL RCEC and pass it down to the connected CXL device's error handler. With this approach the code can entirely be implemented in the PCIe AER driver and is independent of the CXL subsystem. The CXL driver only provides the handler. [1] CXL 3.0 spec: 9.11.8 CXL Devices Attached to an RCH [2] CXL 3.0 spec, 12.2.1.1 RCH Downstream Port-detected Errors [3] CXL 3.0 spec, 8.1.3 PCIe DVSEC for CXL Devices Co-developed-by:
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Terry Bowman authored
The RCH root port contains root command AER registers that should not be enabled.[1] Disable these to prevent root port interrupts. [1] CXL 3.0 - 12.2.1.1 RCH Downstream Port-detected Errors Signed-off-by:
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Terry Bowman authored
RCH downstream port error logging is missing in the current CXL driver. The missing AER and RAS error logging is needed for communicating driver error details to userspace. Update the driver to include PCIe AER and CXL RAS error logging. Add RCH downstream port error handling into the existing RCiEP handler. The downstream port error handler is added to the RCiEP error handler because the downstream port is implemented in a RCRB, is not PCI enumerable, and as a result is not directly accessible to the PCI AER root port driver. The AER root port driver calls the RCiEP handler for handling RCD errors and RCH downstream port protocol errors. Update existing RCiEP correctable and uncorrectable handlers to also call the RCH handler. The RCH handler will read the RCH AER registers, check for error severity, and if an error exists will log using an existing kernel AER trace routine. The RCH handler will also log downstream port RAS errors if they exist. Co-developed-by:
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Terry Bowman authored
The restricted CXL host (RCH) error handler will log protocol errors using AER and RAS status registers. The AER and RAS registers need to be virtually memory mapped before enabling interrupts. Create the initializer function devm_cxl_setup_parent_dport() for this when the endpoint is connected with the dport. The initialization sets up the RCH RAS and AER mappings. Add 'struct cxl_regs' to 'struct cxl_dport' for saving a pointer to the RCH downstream port's AER and RAS registers. Signed-off-by:
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Terry Bowman authored
The CXL error handler currently only logs endpoint RAS status. The CXL topology includes several components providing RAS details to be logged during error handling.[1] Update the current handler's RAS logging to use a RAS register address. Also, update the error handler function names to be consistent with correctable and uncorrectable RAS. This will allow for adding support to log other CXL component's RAS details in the future. [1] CXL3.0 Table 8-22 CXL_Capability_ID Assignment Co-developed-by:
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Terry Bowman authored
The CXL driver plans to use cper_print_aer() for logging restricted CXL host (RCH) AER errors. cper_print_aer() is not currently exported and therefore not usable by the CXL drivers built as loadable modules. Export the cper_print_aer() function. Use the EXPORT_SYMBOL_NS_GPL() variant to restrict the export to CXL drivers. The CONFIG_ACPI_APEI_PCIEAER kernel config is currently used to enable cper_print_aer(). cper_print_aer() logs the AER registers and is useful in PCIE AER logging outside of APEI. Remove the CONFIG_ACPI_APEI_PCIEAER dependency to enable cper_print_aer(). The cper_print_aer() function name implies CPER specific use but is useful in non-CPER cases as well. Rename cper_print_aer() to pci_print_aer(). Also, update cxl_core to import CXL namespace imports. Co-developed-by:
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Robert Richter authored
Restricted CXL host (RCH) downstream port AER information is not currently logged while in the error state. One problem preventing the error logging is the AER and RAS registers are not accessible. The CXL driver requires changes to find RCH downstream port AER and RAS registers for purpose of error logging. RCH downstream ports are not enumerated during a PCI bus scan and are instead discovered using system firmware, ACPI in this case.[1] The downstream port is implemented as a Root Complex Register Block (RCRB). The RCRB is a 4k memory block containing PCIe registers based on the PCIe root port.[2] The RCRB includes AER extended capability registers used for reporting errors. Note, the RCH's AER Capability is located in the RCRB memory space instead of PCI configuration space, thus its register access is different. Existing kernel PCIe AER functions can not be used to manage the downstream port AER capabilities and RAS registers because the port was not enumerated during PCI scan and the registers are not PCI config accessible. Discover RCH downstream port AER extended capability registers. Use MMIO accesses to search for extended AER capability in RCRB register space. [1] CXL 3.0 Spec, 9.11.2 - System Firmware View of CXL 1.1 Hierarchy [2] CXL 3.0 Spec, 8.2.1.1 - RCH Downstream Port RCRB Co-developed-by:
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Robert Richter authored
The Component Register base address @component_reg_phys is no longer used after the rework of the Component Register setup which now uses struct member @reg_map instead. Remove the base address. Signed-off-by:
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Robert Richter authored
The Component Register base address @component_reg_phys is no longer used after the rework of the Component Register setup which now uses struct member @reg_map instead. Remove the base address. Signed-off-by:
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Robert Richter authored
Now, that the Component Register mappings are stored, use them to enable and map the HDM decoder capabilities. The Component Registers do not need to be probed again for this, remove probing code. The HDM capability applies to Endpoints, USPs and VH Host Bridges. The Endpoint's component register mappings are located in the cxlds and else in the port's structure. Duplicate the cxlds->reg_map in port->reg_map for endpoint ports. Signed-off-by:
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Robert Richter authored
Same as for ports and dports, also store the endpoint's Component Register mappings, use struct cxl_dev_state for that. Keep the Component Register base address @component_reg_phys a bit to not break functionality. It will be removed after the transition in a later patch. Signed-off-by:
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Robert Richter authored
The component registers of a component may not exist and cxl_setup_comp_regs() will fail for that reason. In another case, Software may not use and set those registers up. cxl_setup_comp_regs() is then called with a base address of CXL_RESOURCE_NONE. Both are valid cases, but the function returns without initializing the register map. Now, a missing component register block is not necessarily a reason to fail (feature is optional or its existence checked later). Change cxl_setup_comp_regs() to also use components with the component register block missing. Thus, always initialize struct cxl_register_map with valid values, set @dev and make @resource CXL_RESOURCE_NONE. The change is in preparation of follow-on patches. Signed-off-by:
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Robert Richter authored
Name the field @reg_map, because @reg_map->host will be used for mapping operations beyond component registers (i.e. AER registers). This is valid for all occurrences of @comp_map. Change them all. Signed-off-by:
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Dan Williams authored
commit 5d2ffbe4 ("cxl/port: Store the downstream port's Component Register mappings in struct cxl_dport") ...moved the dport component registers from a raw component_reg_phys passed in at dport instantiation time to a 'struct cxl_register_map' populated with both the component register data *and* the "host" device for mapping operations. While typical CXL switch dports are mapped by their associated 'struct cxl_port', an RCH host bridge dport registered by cxl_acpi needs to wait until the cxl_mem driver makes the attachment to map the registers. This is because there are no intervening 'struct cxl_port' instances between the root cxl_port and the endpoint port in an RCH topology. For now just mark the host as NULL in the RCH dport case until code that needs to map the dport registers arrives. This patch is not flagged for -stable since nothing in the current driver uses the dport->comp_map. Now, I am slightly uneasy that cxl_setup_comp_regs() sets map->host to a wrong value and then cxl_dport_setup_regs() fixes it up, but the alternatives I came up with are more messy. For example, adding an @logdev to 'struct cxl_register_map' that the dev_printk()s can fall back to when @host is NULL. I settled on "post-fixup+comment" since it is only RCH dports that have this special case where register probing is split between a host-bridge RCRB lookup and when cxl_mem_probe() does the association of the cxl_memdev and endpoint port. [moved rename of @comp_map to @reg_map into next patch] Fixes: 5d2ffbe4 ("cxl/port: Store the downstream port's Component Register mappings in struct cxl_dport") Signed-off-by:
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Robert Richter authored
The primary role of @dev is to host the mappings for devm operations. @dev is too ambiguous as a name. I.e. when does @dev refer to the 'struct device *' instance that the registers belong, and when does @dev refer to the 'struct device *' instance hosting the mapping for devm operations? Clarify the role of @dev in cxl_register_map by renaming it to @host. Also, rename local variables to 'host' where map->host is used. Signed-off-by:
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Dan Williams authored
The CXL subsystem, at cxl_mem ->probe() time, establishes a lineage of ports (struct cxl_port objects) between an endpoint and the root of a CXL topology. Each port including the endpoint port is attached to the cxl_port driver. Given that setup, it follows that when either any port in that lineage goes through a cxl_port ->remove() event, or the memdev goes through a cxl_mem ->remove() event. The hierarchy below the removed port, or the entire hierarchy if the memdev is removed needs to come down. The delete_endpoint() callback is careful to check whether it is being called to tear down the hierarchy, or if it is only being called to teardown the memdev because an ancestor port is going through ->remove(). That care needs to take the device_lock() of the endpoint's parent. Which requires 2 bugs to be fixed: 1/ A reference on the parent is needed to prevent use-after-free scenarios like this signature: BUG: spinlock bad magic on CPU#0, kworker/u56:0/11 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS edk2-20230524-3.fc38 05/24/2023 Workqueue: cxl_port detach_memdev [cxl_core] RIP: 0010:spin_bug+0x65/0xa0 Call Trace: do_raw_spin_lock+0x69/0xa0 __mutex_lock+0x695/0xb80 delete_endpoint+0xad/0x150 [cxl_core] devres_release_all+0xb8/0x110 device_unbind_cleanup+0xe/0x70 device_release_driver_internal+0x1d2/0x210 detach_memdev+0x15/0x20 [cxl_core] process_one_work+0x1e3/0x4c0 worker_thread+0x1dd/0x3d0 2/ In the case of RCH topologies, the parent device that needs to be locked is not always @port->dev as returned by cxl_mem_find_port(), use endpoint->dev.parent instead. Fixes: 8dd2bc0f ("cxl/mem: Add the cxl_mem driver") Cc: <stable@vger.kernel.org> Reported-by:
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- 27 Oct, 2023 5 commits
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Vishal Verma authored
The cxl-cli unit test for firmware update does operations like starting an asynchronous firmware update, making sure it is in progress, and attempting to cancel it. In some cases, such as with no or minimal dynamic debugging turned on, the firmware update completes too quickly, not allowing the test to have a chance to verify it was in progress. This caused a failure of the signature: expected fw_update_in_progress:true test/cxl-update-firmware.sh: failed at line 88 Fix this by adding a delay (~1.5 - 2 ms) to each firmware transfer request handled by the mocked interface. Reported-by:
Vishal Verma <vishal.l.verma@intel.com> Link: https://lore.kernel.org/r/20231026-vv-fw_upd_test_fix-v2-1-5282fd193883@intel.comSigned-off-by:
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Jim Harris authored
Root decoder granularity must match value from CFWMS, which may not be the region's granularity for non-interleaved root decoders. So when calculating granularities for host bridge decoders, use the region's granularity instead of the root decoder's granularity to ensure the correct granularities are set for the host bridge decoders and any downstream switch decoders. Test configuration is 1 host bridge * 2 switches * 2 endpoints per switch. Region created with 2048 granularity using following command line: cxl create-region -m -d decoder0.0 -w 4 mem0 mem2 mem1 mem3 \ -g 2048 -s 2048M Use "cxl list -PDE | grep granularity" to get a view of the granularity set at each level of the topology. Before this patch: "interleave_granularity":2048, "interleave_granularity":2048, "interleave_granularity":512, "interleave_granularity":2048, "interleave_granularity":2048, "interleave_granularity":512, "interleave_granularity":256, After: "interleave_granularity":2048, "interleave_granularity":2048, "interleave_granularity":4096, "interleave_granularity":2048, "interleave_granularity":2048, "interleave_granularity":4096, "interleave_granularity":2048, Fixes: 27b3f8d1 ("cxl/region: Program target lists") Cc: <stable@vger.kernel.org> Signed-off-by:Jim Harris <jim.harris@samsung.com> Link: https://lore.kernel.org/r/169824893473.1403938.16110924262989774582.stgit@bgt-140510-bm03.eng.stellus.in [djbw: fixup the prebuilt cxl_test region] Signed-off-by:
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Li Zhijian authored
Fix a missed "goto out" to unlock on error to cleanup this splat: WARNING: lock held when returning to user space! 6.6.0-rc3-lizhijian+ #213 Not tainted ------------------------------------------------ cxl/673 is leaving the kernel with locks still held! 1 lock held by cxl/673: #0: ffffffffa013b9d0 (cxl_region_rwsem){++++}-{3:3}, at: commit_store+0x7d/0x3e0 [cxl_core] In terms of user visible impact of this bug for backports: cxl_region_invalidate_memregion() on x86 invokes wbinvd which is a problematic instruction for virtualized environments. So, on virtualized x86, cxl_region_invalidate_memregion() returns an error. This failure case got missed because CXL memory-expander device passthrough is not a production use case, and emulation of CXL devices is typically limited to kernel development builds with CONFIG_CXL_REGION_INVALIDATION_TEST=y, that makes cxl_region_invalidate_memregion() succeed. In other words, the expected exposure of this bug is limited to CXL subsystem development environments using QEMU that neglected CONFIG_CXL_REGION_INVALIDATION_TEST=y. Fixes: d1257d09 ("cxl/region: Move cache invalidation before region teardown, and before setup") Signed-off-by:Li Zhijian <lizhijian@fujitsu.com> Reviewed-by:
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Alison Schofield authored
For auto-discovered regions the driver must assign each target to a valid position in the region interleave set based on the decoder topology. The current implementation fails to parse valid decode topologies, as it does not consider the child offset into a parent port. The sort put all targets of one port ahead of another port when an interleave was expected, causing the region assembly to fail. Replace the existing relative sort with cxl_calc_interleave_pos() that finds the exact position in a region interleave for an endpoint based on a walk up the ancestral tree from endpoint to root decoder. cxl_calc_interleave_pos() was introduced in a prior patch, so the work here is to use it in cxl_region_sort_targets(). Remove the obsoleted helper functions from the prior sort. Testing passes on pre-production hardware with BIOS defined regions that natively trigger this autodiscovery path of the region driver. Testing passes a CXL unit test using the dev_dbg() calculation test (see cxl_region_attach()) across an expanded set of region configs: 1, 1, 1+1, 1+1+1, 2, 2+2, 2+2+2, 2+2+2+2, 4, 4+4, where each number represents the count of endpoints per host bridge. Fixes: a32320b7 ("cxl/region: Add region autodiscovery") Reported-by:
Dmytro Adamenko <dmytro.adamenko@intel.com> Signed-off-by:
Alison Schofield <alison.schofield@intel.com> Reviewed-by:
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Alison Schofield authored
Introduce a calculation to find a target's position in a region interleave. Perform a self-test of the calculation on user-defined regions. The region driver uses the kernel sort() function to put region targets in relative order. Positions are assigned based on each target's index in that sorted list. That relative sort doesn't consider the offset of a port into its parent port which causes some auto-discovered regions to fail creation. In one failure case, a 2 + 2 config (2 host bridges each with 2 endpoints), the sort puts all the targets of one port ahead of another port when they were expected to be interleaved. In preparation for repairing the autodiscovery region assembly, introduce a new method for discovering a target position in the region interleave. cxl_calc_interleave_pos() adds a method to find the target position by ascending from an endpoint to a root decoder. The calculation starts with the endpoint's local position and position in the parent port. It traverses towards the root decoder and examines both position and ways in order to allow the position to be refined all the way to the root decoder. This calculation: position = position * parent_ways + parent_pos; applied iteratively yields the correct position. Include a self-test that exercises this new position calculation against every successfully configured user-defined region. Signed-off-by:
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- 26 Oct, 2023 2 commits
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Vishal Verma authored
tools/testing/cxl contains the unit test infrastructure for mocking CXL hierarchies. These are under the purview of the CXL subsystem maintainers. Add the 'F:' entry for this to MAINTAINERS so that get_maintainer.pl works as expected for patches to this area. Signed-off-by:
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Alison Schofield authored
match_decoder_by_range() and decoder_match_range() both determine if an HPA range matches a decoder. The first does it for root decoders and the second one operates on switch decoders. Tidy these up with clear naming and make the switch helper more like the root decoder helper in style and functionality. Make it take the actual range, rather than an endpoint decoder from which it extracts the range. Require an exact match on switch decoders, because unlike a root decoder that maps an entire region, Linux only supports 1:1 mapping of switch to endpoint decoders. Note that root-decoders are a super-set of switch-decoders and the range they cover is a super-set of a region, hence the use of range_contains() for that case. Aside from aesthetics and maintainability, this is in preparation for reuse. Signed-off-by:
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- 24 Oct, 2023 2 commits
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Alison Schofield authored
DEFINE_RES_MEM() is a wrapper around the DEFINE_RES_NAMED() macro which already has the (struct resource) for the compound literal. The user of the macro should not repeat the cast. Cleans up these sparse warnings: drivers/cxl/core/mbox.c:1184:18: warning: cast to non-scalar drivers/cxl/core/mbox.c:1184:18: warning: cast from non-scalar Fixes: 52c4d11f ("resource: Convert DEFINE_RES_NAMED() to be compound literal") Signed-off-by:
Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20230815172052.22514-1-alison.schofield@intel.comSigned-off-by:
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Jim Harris authored
Commit 5e42bcbc ("cxl/region: decrement ->nr_targets on error in cxl_region_attach()") tried to avoid 'eiw' initialization errors when ->nr_targets exceeded 16, by just decrementing ->nr_targets when cxl_region_setup_targets() failed. Commit 86987c76 ("cxl/region: Cleanup target list on attach error") extended that cleanup to also clear cxled->pos and p->targets[pos]. The initialization error was incidentally fixed separately by: Commit 8d428542 ("cxl/region: Fix port setup uninitialized variable warnings") which was merged a few days after 5e42bcbc. But now the original cleanup when cxl_region_setup_targets() fails prevents endpoint and switch decoder resources from being reused: 1) the cleanup does not set the decoder's region to NULL, which results in future dpa_size_store() calls returning -EBUSY 2) the decoder is not properly freed, which results in future commit errors associated with the upstream switch Now that the initialization errors were fixed separately, the proper cleanup for this case is to just return immediately. Then the resources associated with this target get cleanup up as normal when the failed region is deleted. The ->nr_targets decrement in the error case also helped prevent a p->targets[] array overflow, so add a new check to prevent against that overflow. Tested by trying to create an invalid region for a 2 switch * 2 endpoint topology, and then following up with creating a valid region. Fixes: 5e42bcbc ("cxl/region: decrement ->nr_targets on error in cxl_region_attach()") Cc: <stable@vger.kernel.org> Signed-off-by:
Dan Carpenter <dan.carpenter@linaro.org> Reviewed-by:
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- 09 Oct, 2023 3 commits
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Dan Williams authored
Allow for cxl_test regression of the sanitize notifier. Reuse the core setup infrastructure, and trigger notifications upon any sanitize submission with a programmable notification delay. Cc: Davidlohr Bueso <dave@stgolabs.net> Reviewed-by:
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Dan Williams authored
Move @mds out of the event specific 'struct mock_event_store' and into the base 'struct cxl_mockmem_data' directly. This is in preparation for enabling cxl_test to exercise the notifier flow for 'sanitize' operation completion. Reviewed-by:
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Dan Williams authored
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: <TASK> 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: 9cc238c7 ("cxl/pci: Introduce cdevm_file_operations") Reported-by:
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- 06 Oct, 2023 2 commits
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Dan Williams authored
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: 0c36b6ad ("cxl/mbox: Add sanitization handling machinery") Cc: Davidlohr Bueso <dave@stgolabs.net> Reviewed-by:
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Dan Williams authored
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:
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