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path: root/drivers/cxl/core/pci.c
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2025-05-09cxl/pci: Add comments to cxl_hdm_decode_init()Robert Richter
There are various configuration cases of HDM decoder registers causing different code paths. Add comments to cxl_hdm_decode_init() to better explain them. Signed-off-by: Robert Richter <rrichter@amd.com> Reviewed-by: Gregory Price <gourry@gourry.net> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: "Fabio M. De Francesco" <fabio.m.de.francesco@linux.intel.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Tested-by: Gregory Price <gourry@gourry.net> Acked-by: Dan Williams <dan.j.williams@intel.com> Link: https://patch.msgid.link/20250509150700.2817697-4-rrichter@amd.com Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2025-05-09cxl/pci: Moving code in cxl_hdm_decode_init()Robert Richter
Commit 3f9e07531778 ("cxl/pci: simplify the check of mem_enabled in cxl_hdm_decode_init()") changed the code flow in this function. The root port is determined before a check to leave the function. Since the root port is not used by the check it can be moved to run the check first. This improves code readability and avoids unnesessary code execution. Signed-off-by: Robert Richter <rrichter@amd.com> Reviewed-by: Gregory Price <gourry@gourry.net> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Reviewed-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: "Fabio M. De Francesco" <fabio.m.de.francesco@linux.intel.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Tested-by: Gregory Price <gourry@gourry.net> Acked-by: Dan Williams <dan.j.williams@intel.com> Link: https://patch.msgid.link/20250509150700.2817697-3-rrichter@amd.com Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2025-05-09cxl: Remove else after returnRobert Richter
Remove unnecessary 'else' after return. Improves readability of code. It is easier to place comments. Check and fix all occurrences under drivers/cxl/. Signed-off-by: Robert Richter <rrichter@amd.com> Reviewed-by: Gregory Price <gourry@gourry.net> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Reviewed-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: "Fabio M. De Francesco" <fabio.m.de.francesco@linux.intel.com> Tested-by: Gregory Price <gourry@gourry.net> Acked-by: Dan Williams <dan.j.williams@intel.com> Link: https://patch.msgid.link/20250509150700.2817697-2-rrichter@amd.com Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2025-04-09cxl/pci: Drop the parameter is_port of cxl_gpf_get_dvsec()Li Ming
The first parameter of cxl_gpf_get_dvsec() is a struct device, can be used to distinguish if the device is a cxl dport or a cxl pci device by checking the PCIe type of it, so the parameter is_port is unnecessary to cxl_gpf_get_dvsec(), using parameter struct device is enough. Signed-off-by: Li Ming <ming.li@zohomail.com> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Tested-by: Davidlohr Bueso <dave@stgolabs.net> Link: https://patch.msgid.link/20250323093110.233040-4-ming.li@zohomail.com Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2025-04-09cxl/pci: Update Port GPF timeout only when the first EP attachingLi Ming
update_gpf_port_dvsec() is used to update GPF Phase timeout, if a CXL switch is under a CXL root port, update_gpf_port_dvsec() will be invoked on the CXL root port when each cxl memory device under the CXL switch is attaching. It is enough to be invoked once, others are redundant. When the first EP attaching, it always triggers its ancestor dports to locate their own Port GPF DVSEC. The change is that invoking update_gpf_port_dvsec() on these ancestor dports after ancestor dport locating a Port GPF DVSEC. It guarantees that update_gpf_port_dvsec() is invoked on a dport only happens during the first EP attaching. Signed-off-by: Li Ming <ming.li@zohomail.com> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Tested-by: Davidlohr Bueso <dave@stgolabs.net> Link: https://patch.msgid.link/20250323093110.233040-3-ming.li@zohomail.com Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2025-04-09cxl/core: Fix caching dport GPF DVSEC issueLi Ming
Per Table 8-2 in CXL r3.2 section 8.1.1 and CXL r3.2 section 8.1.6, only CXL Downstream switch ports and CXL root ports have GPF DVSEC for CXL Port(DVSEC ID 04h). CXL subsystem has a gpf_dvsec in struct cxl_port which is used to cache the offset of a GPF DVSEC in PCIe configuration space. It will be updated during the first EP attaching to the cxl_port, so the gpf_dvsec can only cache the GPF DVSEC offset of the dport which the first EP is under. Will not have chance to update it during other EPs attaching. That means CXL subsystem will use the same GPF DVSEC offset for all dports under the port, it will be a problem if the GPF DVSEC offset cached in cxl_port is not the right offset for a dport. Moving gpf_dvsec from struct cxl_port to struct cxl_dport, make every cxl dport has their own GPF DVSEC offset caching, and each cxl dport uses its own GPF DVSEC offset for GPF DVSEC accessing. Fixes: a52b6a2c1c99 ("cxl/pci: Support Global Persistent Flush (GPF)") Signed-off-by: Li Ming <ming.li@zohomail.com> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Tested-by: Davidlohr Bueso <dave@stgolabs.net> Link: https://patch.msgid.link/20250323093110.233040-2-ming.li@zohomail.com Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2025-03-14cxl/pci: Introduce cxl_gpf_get_dvsec()Davidlohr Bueso
Add a helper to fetch the port/device GPF dvsecs. This is currently only used for ports, but a later patch to export dirty count to users will make use of the device one. Signed-off-by: Davidlohr Bueso <dave@stgolabs.net> Reviewed-by: Li Ming <ming.li@zohomail.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://patch.msgid.link/20250220220235.276831-2-dave@stgolabs.net Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2025-03-14cxl/pci: Support Global Persistent Flush (GPF)Davidlohr Bueso
Add support for GPF flows. It is found that the CXL specification around this to be a bit too involved from the driver side. And while this should really all handled by the hardware, this patch takes things with a grain of salt. Upon respective port enumeration, both phase timeouts are set to a max of 20 seconds, which is the NMI watchdog default for lockup detection. The premise is that the kernel does not have enough information to set anything better than a max across the board and hope devices finish their GPF flows within the platform energy budget. Timeout detection is based on dirty Shutdown semantics. The driver will mark it as dirty, expecting that the device clear it upon a successful GPF event. The admin may consult the device Health and check the dirty shutdown counter to see if there was a problem with data integrity. [ davej: Explicitly set return to 0 in update_gpf_port_dvsec() ] [ davej: Add spec reference for 'struct cxl_mbox_set_shutdown_state_in ] [ davej: Fix 0-day reported issue ] Signed-off-by: Davidlohr Bueso <dave@stgolabs.net> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Link: https://patch.msgid.link/20250124233533.910535-1-dave@stgolabs.net Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2025-01-29Merge tag 'cxl-for-6.14' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl Pull Compute Express Link (CXL) updates from Dave Jiang: "A tweak to the HMAT output that was acked by Rafael, a prep patch for CXL type2 devices support that's coming soon, refactoring of the CXL regblock enumeration code, and a series of patches to update the event records to CXL spec r3.1: - Move HMAT printouts to pr_debug() - Add CXL type2 support to cxl_dvsec_rr_decode() in preparation for type2 support - A series that updates CXL event records to spec r3.1 and related changes - Refactoring of cxl_find_regblock_instance() to count regblocks" * tag 'cxl-for-6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl: cxl/core/regs: Refactor out functions to count regblocks of given type cxl/test: Update test code for event records to CXL spec rev 3.1 cxl/events: Update Memory Module Event Record to CXL spec rev 3.1 cxl/events: Update DRAM Event Record to CXL spec rev 3.1 cxl/events: Update General Media Event Record to CXL spec rev 3.1 cxl/events: Add Component Identifier formatting for CXL spec rev 3.1 cxl/events: Update Common Event Record to CXL spec rev 3.1 cxl/pci: Add CXL Type 1/2 support to cxl_dvsec_rr_decode() ACPI/HMAT: Move HMAT messages to pr_debug()
2025-01-03driver core: Constify API device_find_child() and adapt for various usagesZijun Hu
Constify the following API: struct device *device_find_child(struct device *dev, void *data, int (*match)(struct device *dev, void *data)); To : struct device *device_find_child(struct device *dev, const void *data, device_match_t match); typedef int (*device_match_t)(struct device *dev, const void *data); with the following reasons: - Protect caller's match data @*data which is for comparison and lookup and the API does not actually need to modify @*data. - Make the API's parameters (@match)() and @data have the same type as all of other device finding APIs (bus|class|driver)_find_device(). - All kinds of existing device match functions can be directly taken as the API's argument, they were exported by driver core. Constify the API and adapt for various existing usages. BTW, various subsystem changes are squashed into this commit to meet 'git bisect' requirement, and this commit has the minimal and simplest changes to complement squashing shortcoming, and that may bring extra code improvement. Reviewed-by: Alison Schofield <alison.schofield@intel.com> Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Acked-by: Uwe Kleine-König <ukleinek@kernel.org> # for drivers/pwm Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> Link: https://lore.kernel.org/r/20241224-const_dfc_done-v5-4-6623037414d4@quicinc.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-01-02cxl/pci: Add CXL Type 1/2 support to cxl_dvsec_rr_decode()Alejandro Lucero
In cxl_dvsec_rr_decode() the pci driver expects to retrieve a cxlds, struct cxl_dev_state, from the driver_data field of struct device. While that works for Type 3, drivers for Type 1/2 devices may not put a cxlds in the driver_data field. In preparation for supporting Type 1/2 devices, replace parameter 'struct device' with 'struct cxl_dev_state' in cxl_dvsec_rr_decode(). Remove the unused parameter 'cxl_port' in cxl_dvsec_rr_decode(). Signed-off-by: Alejandro Lucero <alucerop@amd.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Alison Schofield <alison.schofield@intel.com> Link: https://patch.msgid.link/20241203162112.5088-1-alucerop@amd.com Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2024-12-02module: Convert symbol namespace to string literalPeter Zijlstra
Clean up the existing export namespace code along the same lines of commit 33def8498fdd ("treewide: Convert macro and uses of __section(foo) to __section("foo")") and for the same reason, it is not desired for the namespace argument to be a macro expansion itself. Scripted using git grep -l -e MODULE_IMPORT_NS -e EXPORT_SYMBOL_NS | while read file; do awk -i inplace ' /^#define EXPORT_SYMBOL_NS/ { gsub(/__stringify\(ns\)/, "ns"); print; next; } /^#define MODULE_IMPORT_NS/ { gsub(/__stringify\(ns\)/, "ns"); print; next; } /MODULE_IMPORT_NS/ { $0 = gensub(/MODULE_IMPORT_NS\(([^)]*)\)/, "MODULE_IMPORT_NS(\"\\1\")", "g"); } /EXPORT_SYMBOL_NS/ { if ($0 ~ /(EXPORT_SYMBOL_NS[^(]*)\(([^,]+),/) { if ($0 !~ /(EXPORT_SYMBOL_NS[^(]*)\(([^,]+), ([^)]+)\)/ && $0 !~ /(EXPORT_SYMBOL_NS[^(]*)\(\)/ && $0 !~ /^my/) { getline line; gsub(/[[:space:]]*\\$/, ""); gsub(/[[:space:]]/, "", line); $0 = $0 " " line; } $0 = gensub(/(EXPORT_SYMBOL_NS[^(]*)\(([^,]+), ([^)]+)\)/, "\\1(\\2, \"\\3\")", "g"); } } { print }' $file; done Requested-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://mail.google.com/mail/u/2/#inbox/FMfcgzQXKWgMmjdFwwdsfgxzKpVHWPlc Acked-by: Greg KH <gregkh@linuxfoundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2024-09-22cxl: Calculate region bandwidth of targets with shared upstream linkDave Jiang
The current bandwidth calculation aggregates all the targets. This simple method does not take into account where multiple targets sharing under a switch or a root port where the aggregated bandwidth can be greater than the upstream link of the switch. To accurately account for the shared upstream uplink cases, a new update function is introduced by walking from the leaves to the root of the hierarchy and clamp the bandwidth in the process as needed. This process is done when all the targets for a region are present but before the final values are send to the HMAT handling code cached access_coordinate targets. The original perf calculation path was kept to calculate the latency performance data that does not require the shared link consideration. The shared upstream link calculation is done as a second pass when all the endpoints have arrived. Testing is done via qemu with CXL hierarchy. run_qemu[1] is modified to support several CXL hierarchy layouts. The following layouts are tested: HB: Host Bridge RP: Root Port SW: Switch EP: End Point 2 HB 2 RP 2 EP: resulting bandwidth: 624 1 HB 2 RP 2 EP: resulting bandwidth: 624 2 HB 2 RP 2 SW 4 EP: resulting bandwidth: 624 Current testing, perf number from SRAT/HMAT is hacked into the kernel code. However with new QEMU support of Generic Target Port that's incoming, the perf data injection is no longer needed. [1]: https://github.com/pmem/run_qemu Suggested-by: Jonathan Cameron <jonathan.cameron@huawei.com> Link: https://lore.kernel.org/linux-cxl/20240501152503.00002e60@Huawei.com/ Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Alison Schofield <alison.schofield@intel.com> Acked-by: Dan Williams <dan.j.williams@intel.com> Link: https://patch.msgid.link/20240904001316.1688225-3-dave.jiang@intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2024-09-09cxl/pci: simplify the check of mem_enabled in cxl_hdm_decode_init()Yanfei Xu
Cases can be divided into two categories which are DVSEC range enabled and not enabled when HDM decoders exist but is not enabled. To avoid checking info->mem_enabled, which indicates the enablement of DVSEC range, every time, we can check !info->mem_enabled once in advance. This simplification can make the code clearer. No functional change intended. Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Yanfei Xu <yanfei.xu@intel.com> Reviewed-by: Alison Schofield <alison.schofield@intel.com> Link: https://patch.msgid.link/20240828084231.1378789-5-yanfei.xu@intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2024-09-09cxl/pci: Check Mem_info_valid bit for each applicable DVSECYanfei Xu
In theory a device might set the mem_info_valid bit for a first range after it is ready but before as second range has reached that state. Therefore, the correct approach is to check the Mem_info_valid bit for each applicable DVSEC range against HDM_COUNT, rather than only for the DVSEC range 1. Consequently, let's move the check into the "for loop" that handles each DVSEC range. Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Yanfei Xu <yanfei.xu@intel.com> Reviewed-by: Alison Schofield <alison.schofield@intel.com> Link: https://patch.msgid.link/20240828084231.1378789-4-yanfei.xu@intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2024-09-09cxl/pci: Remove duplicated implementation of waiting for memory_info_validYanfei Xu
commit ce17ad0d5498 ("cxl: Wait Memory_Info_Valid before access memory related info") added another implementation, which is cxl_dvsec_mem_range_valid(), of waiting for memory_info_valid without realizing it duplicated wait_for_valid(). Remove wait_for_valid() and retain cxl_dvsec_mem_range_valid() as the former is hardcoded to check only the Memory_Info_Valid bit of DVSEC range 1, while the latter allows for selection between DVSEC range 1 or 2 via parameter. Suggested-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Yanfei Xu <yanfei.xu@intel.com> Reviewed-by: Alison Schofield <alison.schofield@intel.com> Link: https://patch.msgid.link/20240828084231.1378789-3-yanfei.xu@intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2024-09-09cxl/pci: Fix to record only non-zero rangesYanfei Xu
The function cxl_dvsec_rr_decode() retrieves and records DVSEC ranges into info->dvsec_range[], regardless of whether it is non-zero range, and the variable info->ranges indicates the number of non-zero ranges. However, in cxl_hdm_decode_init(), the validation for info->dvsec_range[] occurs in a for loop that iterates based on info->ranges. It may result in zero range to be validated but non-zero range not be validated, in turn, the number of allowed ranges is to be 0. Address it by only record non-zero ranges. This fix is not urgent as it requires a configuration that zeroes out the first dvsec range while populating the second. This has not been observed, but it is theoretically possible. If this gets picked up for -stable, no harm done, but there is no urgency to backport. Fixes: 560f78559006 ("cxl/pci: Retrieve CXL DVSEC memory info") Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Yanfei Xu <yanfei.xu@intel.com> Reviewed-by: Alison Schofield <alison.schofield@intel.com> Link: https://patch.msgid.link/20240828084231.1378789-2-yanfei.xu@intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2024-09-03cxl/pci: Remove duplicate host_bridge->native_aer checkingLi Ming
cxl_dport_init_ras_reporting() already checks host_bridge->native_aer before invoking cxl_disable_rch_root_ints(), so cxl_disable_rch_root_ints() does not need to check it again. Signed-off-by: Li Ming <ming4.li@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://patch.msgid.link/20240830061308.2327065-3-ming4.li@intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2024-09-03cxl/pci: cxl_dport_map_rch_aer() cleanupLi Ming
cxl_dport_map_ras() is used to map CXL RAS capability, the RCH AER capability should not be mapped in the function but should mapped in cxl_dport_init_ras_reporting(). Moving cxl_dport_map_ras() out of cxl_dport_map_ras() and into cxl_dport_init_ras_reporting(). In cxl_dport_init_ras_reporting(), the AER capability position in RCRB will be located but the position is only used in cxl_dport_map_rch_aer(), getting the position in cxl_dport_map_rch_aer() rather than cxl_dport_init_ras_reporting() is more reasonable and makes the code clearer. Besides, some local variables in cxl_dport_map_rch_aer() are unnecessary, remove them to make the function more concise. Signed-off-by: Li Ming <ming4.li@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://patch.msgid.link/20240830061308.2327065-2-ming4.li@intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2024-09-03cxl/pci: Rename cxl_setup_parent_dport() and cxl_dport_map_regs()Li Ming
The name of cxl_setup_parent_dport() function is not clear, the function is used to initialize AER and RAS capabilities on a dport, therefore, rename the function to cxl_dport_init_ras_reporting(), it is easier for user to understand what the function does. Besides, adjust the order of the function parameters, the subject of cxl_dport_init_ras_reporting() is a cxl dport, so a struct cxl_dport as the first parameter of the function should be better. cxl_dport_map_regs() is used to map CXL RAS capability on a cxl dport, using cxl_dport_map_ras() as the function name. Signed-off-by: Li Ming <ming4.li@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://patch.msgid.link/20240830061308.2327065-1-ming4.li@intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2024-09-03cxl/port: Use __free() to drop put_device() for cxl_portLi Ming
Using scope-based resource management __free() marco with a new helper called put_cxl_port() to drop open coded the put_device() used to dereference the 'struct device' in cxl_port. Suggested-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Li Ming <ming4.li@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://patch.msgid.link/20240830013138.2256244-1-ming4.li@intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2024-08-09cxl/pci: Get AER capability address from RCRB only for RCH dportLi Ming
cxl_setup_parent_dport() needs to get RCH dport AER capability address from RCRB to disable AER interrupt. The function does not check if dport is RCH dport, it will get a wrong pci_host_bridge structure by dport_dev in VH case because dport_dev points to a pci device(RP or switch DSP) rather than a pci host bridge device. Fixes: f05fd10d138d ("cxl/pci: Add RCH downstream port AER register discovery") Signed-off-by: Li Ming <ming4.li@intel.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Tested-by: Ira Weiny <ira.weiny@intel.com> Tested-by: Alison Schofield <alison.schofield@intel.com> Link: https://patch.msgid.link/20240809082750.3015641-2-ming4.li@intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2024-07-17cxl/core/pci: Move reading of control register to immediately before usageForyun Ma
Relocate the reading of the DVSEC control register to immediately before usage and avoid unnecessary PCI config access from the read if DVSEC capability check, hdm_count check, or device validity check results in failure. Signed-off-by: Foryun Ma <foryun.ma@jaguarmicro.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Alison Schofield <alison.schofield@intel.com> Link: https://patch.msgid.link/20240604032151.655-1-foryun.ma@jaguarmicro.com Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2024-05-08cxl: Add post-reset warning if reset results in loss of previously committed ↵Dave Jiang
HDM decoders Secondary Bus Reset (SBR) is equivalent to a device being hot removed and inserted again. Doing a SBR on a CXL type 3 device is problematic if the exported device memory is part of system memory that cannot be offlined. The event is equivalent to violently ripping out that range of memory from the kernel. While the hardware requires the "Unmask SBR" bit set in the Port Control Extensions register and the kernel currently does not unmask it, user can unmask this bit via setpci or similar tool. The driver does not have a way to detect whether a reset coming from the PCI subsystem is a Function Level Reset (FLR) or SBR. The only way to detect is to note if a decoder is marked as enabled in software but the decoder control register indicates it's not committed. Add a helper function to find discrepancy between the decoder software state versus the hardware register state. Suggested-by: Dan Williams <dan.j.williams@intel.com> Link: https://lore.kernel.org/r/20240502165851.1948523-6-dave.jiang@intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com>
2024-05-08PCI/CXL: Move CXL Vendor ID to pci_ids.hDave Jiang
Move PCI_DVSEC_VENDOR_ID_CXL in CXL private code to PCI_VENDOR_ID_CXL in pci_ids.h in order to be utilized in PCI subsystem. While the CXL Vendor ID (0x1e98) is not listed in the PCI SIG "Member Companies" database at https://pcisig.com/membership/member-companies, the SIG has confirmed that it is reserved by CXL. Link: https://lore.kernel.org/r/20240502165851.1948523-2-dave.jiang@intel.com Suggested-by: Bjorn Helgaas <helgaas@kernel.org> Link: https://lore.kernel.org/linux-cxl/20240402172323.GA1818777@bhelgaas/ Signed-off-by: Dave Jiang <dave.jiang@intel.com> [bhelgaas: update commit log] Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com>
2024-03-13lib/firmware_table: Provide buffer length argument to cdat_table_parse()Robert Richter
There exist card implementations with a CDAT table using a fixed size buffer, but with entries filled in that do not fill the whole table length size. Then, the last entry in the CDAT table may not mark the end of the CDAT table buffer specified by the length field in the CDAT header. It can be shorter with trailing unused (zero'ed) data. The actual table length is determined while reading all CDAT entries of the table with DOE. If the table is greater than expected (containing zero'ed trailing data), the CDAT parser fails with: [ 48.691717] Malformed DSMAS table length: (24:0) [ 48.702084] [CDAT:0x00] Invalid zero length [ 48.711460] cxl_port endpoint1: Failed to parse CDAT: -22 In addition, a check of the table buffer length is missing to prevent an out-of-bound access then parsing the CDAT table. Hardening code against device returning borked table. Fix that by providing an optional buffer length argument to acpi_parse_entries_array() that can be used by cdat_table_parse() to propagate the buffer size down to its users to check the buffer length. This also prevents a possible out-of-bound access mentioned. Add a check to warn about a malformed CDAT table length. Cc: Rafael J. Wysocki <rafael@kernel.org> Cc: Len Brown <lenb@kernel.org> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Robert Richter <rrichter@amd.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/ZdEnopFO0Tl3t2O1@rric.localdomain Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2024-03-12cxl/pci: Get rid of pointer arithmetic reading CDAT tableRobert Richter
Reading the CDAT table using DOE requires a Table Access Response Header in addition to the CDAT entry. In current implementation this has caused offsets with sizeof(__le32) to the actual buffers. This led to hardly readable code and even bugs. E.g., see fix of devm_kfree() in read_cdat_data(): commit c65efe3685f5 ("cxl/cdat: Free correct buffer on checksum error") Rework code to avoid calculations with sizeof(__le32). Introduce struct cdat_doe_rsp for this which contains the Table Access Response Header and a variable payload size for various data structures afterwards to access the CDAT table and its CDAT Data Structures without recalculating buffer offsets. Cc: Lukas Wunner <lukas@wunner.de> Cc: Fan Ni <nifan.cxl@gmail.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Robert Richter <rrichter@amd.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/20240216155844.406996-3-rrichter@amd.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2024-03-12cxl/pci: Rename DOE mailbox handle to doe_mbRobert Richter
Trivial variable rename for the DOE mailbox handle from cdat_doe to doe_mb. The variable name cdat_doe is too ambiguous, use doe_mb that is commonly used for the mailbox. Signed-off-by: Robert Richter <rrichter@amd.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/20240216155844.406996-2-rrichter@amd.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2024-02-16cxl/pci: Fix disabling memory if DVSEC CXL Range does not match a CFMWS windowRobert Richter
The Linux CXL subsystem is built on the assumption that HPA == SPA. That is, the host physical address (HPA) the HDM decoder registers are programmed with are system physical addresses (SPA). During HDM decoder setup, the DVSEC CXL range registers (cxl-3.1, 8.1.3.8) are checked if the memory is enabled and the CXL range is in a HPA window that is described in a CFMWS structure of the CXL host bridge (cxl-3.1, 9.18.1.3). Now, if the HPA is not an SPA, the CXL range does not match a CFMWS window and the CXL memory range will be disabled then. The HDM decoder stops working which causes system memory being disabled and further a system hang during HDM decoder initialization, typically when a CXL enabled kernel boots. Prevent a system hang and do not disable the HDM decoder if the decoder's CXL range is not found in a CFMWS window. Note the change only fixes a hardware hang, but does not implement HPA/SPA translation. Support for this can be added in a follow on patch series. Signed-off-by: Robert Richter <rrichter@amd.com> Fixes: 34e37b4c432c ("cxl/port: Enable HDM Capability after validating DVSEC Ranges") Cc: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20240216160113.407141-1-rrichter@amd.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2024-01-29cxl/pci: Skip to handle RAS errors if CXL.mem device is detachedLi Ming
The PCI AER model is an awkward fit for CXL error handling. While the expectation is that a PCI device can escalate to link reset to recover from an AER event, the same reset on CXL amounts to a surprise memory hotplug of massive amounts of memory. At present, the CXL error handler attempts some optimistic error handling to unbind the device from the cxl_mem driver after reaping some RAS register values. This results in a "hopeful" attempt to unplug the memory, but there is no guarantee that will succeed. A subsequent AER notification after the memdev unbind event can no longer assume the registers are mapped. Check for memdev bind before reaping status register values to avoid crashes of the form: BUG: unable to handle page fault for address: ffa00000195e9100 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page [...] RIP: 0010:__cxl_handle_ras+0x30/0x110 [cxl_core] [...] Call Trace: <TASK> ? __die+0x24/0x70 ? page_fault_oops+0x82/0x160 ? kernelmode_fixup_or_oops+0x84/0x110 ? exc_page_fault+0x113/0x170 ? asm_exc_page_fault+0x26/0x30 ? __pfx_dpc_reset_link+0x10/0x10 ? __cxl_handle_ras+0x30/0x110 [cxl_core] ? find_cxl_port+0x59/0x80 [cxl_core] cxl_handle_rp_ras+0xbc/0xd0 [cxl_core] cxl_error_detected+0x6c/0xf0 [cxl_core] report_error_detected+0xc7/0x1c0 pci_walk_bus+0x73/0x90 pcie_do_recovery+0x23f/0x330 Longer term, the unbind and PCI_ERS_RESULT_DISCONNECT behavior might need to be replaced with a new PCI_ERS_RESULT_PANIC. Fixes: 6ac07883dbb5 ("cxl/pci: Add RCH downstream port error logging") Cc: stable@vger.kernel.org Suggested-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Li Ming <ming4.li@intel.com> Link: https://lore.kernel.org/r/20240129131856.2458980-1-ming4.li@intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2023-12-22cxl: Calculate and store PCI link latency for the downstream portsDave Jiang
The latency is calculated by dividing the flit size over the bandwidth. Add support to retrieve the flit size for the CXL switch device and calculate the latency of the PCIe link. Cache the latency number with cxl_dport. Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Dave Jiang <dave.jiang@intel.com> Link: https://lore.kernel.org/r/170319621931.2212653.6800240203604822886.stgit@djiang5-mobl3 Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2023-12-08cxl/cdat: Free correct buffer on checksum errorIra Weiny
The new 6.7-rc1 kernel now checks the checksum on CDAT data. While using a branch of Fan's DCD qemu work (and specifying DCD devices), the following splat was observed. WARNING: CPU: 1 PID: 1384 at drivers/base/devres.c:1064 devm_kfree+0x4f/0x60 ... RIP: 0010:devm_kfree+0x4f/0x60 ... ? devm_kfree+0x4f/0x60 read_cdat_data+0x1a0/0x2a0 [cxl_core] cxl_port_probe+0xdf/0x200 [cxl_port] ... The issue in qemu is still unknown but the spat is a straight forward bug in the CDAT checksum processing code. Use a CDAT buffer variable to ensure the devm_free() works correctly on error. Fixes: 670e4e88f3b1 ("cxl: Add checksum verification to CDAT from CXL") Signed-off-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Reviewed-by: Fan Ni <fan.ni@samsung.com> Reviewed-by: Robert Richter <rrichter@amd.com> Link: http://lore.kernel.org/r/20231116-fix-cdat-devm-free-v1-1-b148b40707d7@intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2023-11-02cxl/pci: Change CXL AER support check to use native AERTerry Bowman
Native CXL protocol errors are delivered to the OS through AER reporting. The owner of AER owns CXL Protocol error management with respect to _OSC negotiation.[1] CXL device errors are handled by a separate interrupt with native control gated by _OSC control field 'CXL Memory Error Reporting Control'. The CXL driver incorrectly checks for 'CXL Memory Error Reporting Control' before accessing AER registers and caching RCH downport AER registers. Replace the current check in these 2 cases with native AER checks. [1] CXL 3.0 - 9.17.2 CXL _OSC, Table-9-26, Interpretation of CXL _OSC Support Fields, p.641 Fixes: f05fd10d138d ("cxl/pci: Add RCH downstream port AER register discovery") Signed-off-by: Terry Bowman <terry.bowman@amd.com> Reviewed-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com> Link: https://lore.kernel.org/r/20231102155232.1421261-1-terry.bowman@amd.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2023-10-31Merge branch 'for-6.7/cxl-qtg' into cxl/nextDan Williams
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.
2023-10-27cxl: Add support for reading CXL switch CDAT tableDave Jiang
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: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Dave Jiang <dave.jiang@intel.com> Link: https://lore.kernel.org/r/169713682855.2205276.6418370379144967443.stgit@djiang5-mobl3 Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2023-10-27cxl: Add checksum verification to CDAT from CXLDave Jiang
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: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Signed-off-by: Dave Jiang <dave.jiang@intel.com> Link: https://lore.kernel.org/r/169713682277.2205276.2687265961314933628.stgit@djiang5-mobl3 Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2023-10-27cxl/pci: Disable root port interrupts in RCH modeTerry Bowman
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: Terry Bowman <terry.bowman@amd.com> Signed-off-by: Robert Richter <rrichter@amd.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Link: https://lore.kernel.org/r/20231018171713.1883517-17-rrichter@amd.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2023-10-27cxl/pci: Add RCH downstream port error loggingTerry Bowman
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: Robert Richter <rrichter@amd.com> Signed-off-by: Terry Bowman <terry.bowman@amd.com> Signed-off-by: Robert Richter <rrichter@amd.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Link: https://lore.kernel.org/r/20231018171713.1883517-16-rrichter@amd.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2023-10-27cxl/pci: Map RCH downstream AER registers for logging protocol errorsTerry Bowman
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: Terry Bowman <terry.bowman@amd.com> Co-developed-by: Robert Richter <rrichter@amd.com> Signed-off-by: Robert Richter <rrichter@amd.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/20231018171713.1883517-15-rrichter@amd.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2023-10-27cxl/pci: Update CXL error logging to use RAS register addressTerry Bowman
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: Robert Richter <rrichter@amd.com> Signed-off-by: Terry Bowman <terry.bowman@amd.com> Signed-off-by: Robert Richter <rrichter@amd.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Link: https://lore.kernel.org/r/20231018171713.1883517-14-rrichter@amd.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2023-10-27cxl/pci: Add RCH downstream port AER register discoveryRobert Richter
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: Robert Richter <rrichter@amd.com> Signed-off-by: Terry Bowman <terry.bowman@amd.com> Signed-off-by: Robert Richter <rrichter@amd.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Link: https://lore.kernel.org/r/20231018171713.1883517-12-rrichter@amd.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2023-06-25Merge branch 'for-6.5/cxl-rch-eh' into for-6.5/cxlDan Williams
Pick up the first half of the RCH error handling series. The back half needs some fixups for test regressions. Small conflicts with the PMU work around register enumeration and setup helpers.
2023-06-25Revert "cxl/port: Enable the HDM decoder capability for switch ports"Dan Williams
commit eb0764b822b9 ("cxl/port: Enable the HDM decoder capability for switch ports") ...was added on the observation of CXL memory not being accessible after setting up a region on a "cold-plugged" device. A "cold-plugged" CXL device is one that was not present at boot, so platform-firmware/BIOS has no chance to set it up. While it is true that the debug found the enable bit clear in the host-bridge's instance of the global control register (CXL 3.0 8.2.4.19.2 CXL HDM Decoder Global Control Register), that bit is described as: "This bit is only applicable to CXL.mem devices and shall return 0 on CXL Host Bridges and Upstream Switch Ports." So it is meant to be zero, and further testing confirmed that this "fix" had no effect on the failure. Revert it, and be more vigilant about proposed fixes in the future. Since the original copied stable@, flag this revert for stable@ as well. Cc: <stable@vger.kernel.org> Fixes: eb0764b822b9 ("cxl/port: Enable the HDM decoder capability for switch ports") Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Link: https://lore.kernel.org/r/168685882012.3475336.16733084892658264991.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2023-06-25cxl: Rename 'uport' to 'uport_dev'Dan Williams
For symmetry with the recent rename of ->dport_dev for a 'struct cxl_dport', add the "_dev" suffix to the ->uport property of a 'struct cxl_port'. These devices represent the downstream-port-device and upstream-port-device respectively in the CXL/PCIe topology. Signed-off-by: Terry Bowman <terry.bowman@amd.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/20230622205523.85375-6-terry.bowman@amd.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2023-05-18cxl: Wait Memory_Info_Valid before access memory related infoDave Jiang
The Memory_Info_Valid bit (CXL 3.0 8.1.3.8.2) indicates that the CXL Range Size High and Size Low registers are valid. The bit must be set within 1 second of reset deassertion to the device. Check valid bit before we check the Memory_Active bit when waiting for cxl_await_media_ready() to ensure that the memory info is valid for consumption. Also ensures both DVSEC ranges 1 and 2 are ready if DVSEC Capability indicates they are both supported. Fixes: 523e594d9cc0 ("cxl/pci: Implement wait for media active") Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Dave Jiang <dave.jiang@intel.com> Link: https://lore.kernel.org/r/168444687469.3134781.11033518965387297327.stgit@djiang5-mobl3 Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2023-05-18cxl/port: Enable the HDM decoder capability for switch portsDan Williams
Derick noticed, when testing hot plug, that hot-add behaves nominally after a removal. However, if the hot-add is done without a prior removal, CXL.mem accesses fail. It turns out that the original implementation of the port driver and region programming wrongly assumed that platform-firmware always enables the host-bridge HDM decoder capability. Add support turning on switch-level HDM decoders in the case where platform-firmware has not. The implementation is careful to only arrange for the enable to be undone if the current instance of the driver was the one that did the enable. This is to interoperate with platform-firmware that may expect CXL.mem to remain active after the driver is shutdown. This comes at the cost of potentially not shutting down the enable on kexec flows, but it is mitigated by the fact that the related HDM decoders still need to be enabled on an individual basis. Cc: <stable@vger.kernel.org> Reported-by: Derick Marks <derick.w.marks@intel.com> Fixes: 54cdbf845cf7 ("cxl/port: Add a driver for 'struct cxl_port' objects") Reviewed-by: Ira Weiny <ira.weiny@intel.com> Link: https://lore.kernel.org/r/168437998331.403037.15719879757678389217.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2023-05-13cxl: Add missing return to cdat read error pathDave Jiang
Add a return to the error path when cxl_cdat_read_table() fails. Current code continues with the table pointer points to freed memory. Fixes: 7a877c923995 ("cxl/pci: Simplify CDAT retrieval error path") Signed-off-by: Dave Jiang <dave.jiang@intel.com> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Link: https://lore.kernel.org/r/168382793506.3510737.4792518576623749076.stgit@djiang5-mobl3 Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2023-04-22cxl/port: Fix port to pci device assumptions in read_cdat_data()Dan Williams
Not all endpoint CXL ports are associated with PCI devices. The cxl_test infrastructure models 'struct cxl_port' instances hosted by platform devices. Teach read_cdat_data() to be careful about non-pci hosted cxl_memdev instances. Otherwise, cxl_test crashes with this signature: RIP: 0010:xas_start+0x6d/0x290 [..] Call Trace: <TASK> xas_load+0xa/0x50 xas_find+0x25b/0x2f0 xa_find+0x118/0x1d0 pci_find_doe_mailbox+0x51/0xc0 read_cdat_data+0x45/0x190 [cxl_core] cxl_port_probe+0x10a/0x1e0 [cxl_port] cxl_bus_probe+0x17/0x50 [cxl_core] Some other cleanups are included like removing the single-use @uport variable, and removing the indirection through 'struct cxl_dev_state' to lookup the device that registered the memdev and may be a pci device. Fixes: af0a6c3587dc ("cxl/pci: Use CDAT DOE mailbox created by PCI core") Reviewed-by: Lukas Wunner <lukas@wunner.de> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/168213190748.708404.16215095414060364800.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2023-04-18cxl/pci: Rightsize CDAT response allocationLukas Wunner
Jonathan notes that cxl_cdat_get_length() and cxl_cdat_read_table() allocate 32 dwords for the DOE response even though it may be smaller. In the case of cxl_cdat_get_length(), only the second dword of the response is of interest (it contains the length). So reduce the allocation to 2 dwords and let DOE discard the remainder. In the case of cxl_cdat_read_table(), a correctly sized allocation for the full CDAT already exists. Let DOE write each table entry directly into that allocation. There's a snag in that the table entry is preceded by a Table Access Response Header (1 dword, CXL 3.0 table 8-14). Save the last dword of the previous table entry, let DOE overwrite it with the header of the next entry and restore it afterwards. The resulting CDAT is preceded by 4 unavoidable useless bytes. Increase the allocation size accordingly. The buffer overflow check in cxl_cdat_read_table() becomes unnecessary because the remaining bytes in the allocation are tracked in "length", which is passed to DOE and limits how many bytes it writes to the allocation. Additionally, cxl_cdat_read_table() bails out if the DOE response is truncated due to insufficient space. Tested-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Lukas Wunner <lukas@wunner.de> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Dave Jiang <dave.jiang@intel.com> Link: https://lore.kernel.org/r/7a4e1f86958a79a70f29b96a92199522f08f8322.1678543498.git.lukas@wunner.de Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2023-04-18cxl/pci: Simplify CDAT retrieval error pathDave Jiang
The cdat.table and cdat.length fields in struct cxl_port are set before CDAT retrieval and must therefore be unset on failure. Simplify by setting only on success. Suggested-by: Jonathan Cameron <Jonathan.Cameron@Huawei.com> Link: https://lore.kernel.org/linux-cxl/20230209113422.00007017@Huawei.com/ Signed-off-by: Dave Jiang <dave.jiang@intel.com> [lukas: rebase and rephrase commit message] Signed-off-by: Lukas Wunner <lukas@wunner.de> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Acked-by: Bjorn Helgaas <bhelgaas@google.com> Link: https://lore.kernel.org/r/7a5c7104fb6a3016dbaec1c5d0ed34619ea11a0c.1678543498.git.lukas@wunner.de Signed-off-by: Dan Williams <dan.j.williams@intel.com>