在 2024/6/21 1:02, Jonathan Cameron 写道:
On Wed, 19 Jun 2024 00:53:10 +0800 Shiyang Ruan <ruansy.fnst@xxxxxxxxxxx> wrote:Background: Since CXL device is a memory device, while CPU consumes a poison page of CXL device, it always triggers a MCE by interrupt (INT18), no matter which-First path is configured. This is the first report. Then currently, in FW-First path, the poison event is transferred according to the following process: CXL device -> firmware -> OS:ACPI->APEI->GHES -> CPER -> trace report. This is the second one. These two reports are indicating the same poisoning page, which is the so-called "duplicate report"[1]. And the memory_failure() handling I'm trying to add in OS-First path could also be another duplicate report. Hope the flow below could make it easier to understand: CPU accesses bad memory on CXL device, then -> MCE (INT18), *always* report (1) -> * FW-First (implemented now) -> CXL device -> FW -> OS:ACPI->APEI->GHES->CPER -> trace report (2.a) * OS-First (not implemented yet, I'm working on it) -> CXL device -> MSI -> OS:CXL driver -> memory_failure() (2.b) so, the (1) and (2.a/b) are duplicated. (I didn't get response in my reply for [1] while I have to make patch to solve this problem, so please correct me if my understanding is wrong.) This patch adds a new notifier_block and MCE_PRIO_CXL, for CXL memdev to check whether the current poison page has been reported (if yes, stop the notifier chain, won't call the following memory_failure() to report), into `x86_mce_decoder_chain`. In this way, if the poison page already handled(recorded and reported) in (1) or (2), the other one won't duplicate the report. The record could be clear when cxl_clear_poison() is called. [1] https://lore.kernel.org/linux-cxl/664d948fb86f0_e8be294f8@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.notmuch/ Signed-off-by: Shiyang Ruan <ruansy.fnst@xxxxxxxxxxx>So poison can be cleared in a number of ways and a CXL poison clear command is unfortunately only one of them. Some architectures have instructions that guarantee to write a whole cacheline and can clear things as well. I believe x86 does for starters.
According to the CXL Spec, to clear an error record on device, an explicit clear operation is required (I think this means sending a mbox command). I'm not sure if it is able to clear device error by just writing a whole cacheline.
+CC linux-edac and related maintainers / reviewers.
linux-mm and hwpoison maintainer.
So I think this needs a more general solution that encompasses
more general cleanup of poison.
Trivial comments inline.
Thanks
Jonathan--- arch/x86/include/asm/mce.h | 1 + drivers/cxl/core/mbox.c | 130 +++++++++++++++++++++++++++++++++++++ drivers/cxl/core/memdev.c | 6 +- drivers/cxl/cxlmem.h | 3 + 4 files changed, 139 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h index dfd2e9699bd7..d8109c48e7d9 100644 --- a/arch/x86/include/asm/mce.h +++ b/arch/x86/include/asm/mce.h @@ -182,6 +182,7 @@ enum mce_notifier_prios { MCE_PRIO_NFIT, MCE_PRIO_EXTLOG, MCE_PRIO_UC, + MCE_PRIO_CXL, MCE_PRIO_EARLY, MCE_PRIO_CEC, MCE_PRIO_HIGHEST = MCE_PRIO_CEC diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c index 2626f3fff201..0eb3c5401e81 100644 --- a/drivers/cxl/core/mbox.c +++ b/drivers/cxl/core/mbox.c @@ -4,6 +4,8 @@ #include <linux/debugfs.h> #include <linux/ktime.h> #include <linux/mutex.h> +#include <linux/notifier.h> +#include <asm/mce.h> #include <asm/unaligned.h> #include <cxlpci.h> #include <cxlmem.h> @@ -880,6 +882,9 @@ void cxl_event_trace_record(const struct cxl_memdev *cxlmd, if (cxlr) hpa = cxl_trace_hpa(cxlr, cxlmd, dpa);+ if (hpa != ULLONG_MAX && cxl_mce_recorded(hpa))+ return; + if (event_type == CXL_CPER_EVENT_GEN_MEDIA) trace_cxl_general_media(cxlmd, type, cxlr, hpa, &evt->gen_media); @@ -1408,6 +1413,127 @@ int cxl_poison_state_init(struct cxl_memdev_state *mds) } EXPORT_SYMBOL_NS_GPL(cxl_poison_state_init, CXL);+struct cxl_mce_record {+ struct list_head node; + u64 hpa; +}; +LIST_HEAD(cxl_mce_records); +DEFINE_MUTEX(cxl_mce_mutex); + +bool cxl_mce_recorded(u64 hpa) +{ + struct cxl_mce_record *cur, *next, *rec; + int rc; + + rc = mutex_lock_interruptible(&cxl_mce_mutex);guard(mutex)(&cxl_mce_muted);+ if (rc) + return false; + + list_for_each_entry_safe(cur, next, &cxl_mce_records, node) { + if (cur->hpa == hpa) { + mutex_unlock(&cxl_mce_mutex); + return true; + } + } + + rec = kmalloc(sizeof(struct cxl_mce_record), GFP_KERNEL); + rec->hpa = hpa; + list_add(&cxl_mce_records, &rec->node); + + mutex_unlock(&cxl_mce_mutex); + + return false; +} + +void cxl_mce_clear(u64 hpa) +{ + struct cxl_mce_record *cur, *next; + int rc; + + rc = mutex_lock_interruptible(&cxl_mce_mutex);Maybe cond_guard().
Ok, this is better. I'll use automatic clean locks instead. -- Thanks, Ruan.
+ if (rc) + return; + + list_for_each_entry_safe(cur, next, &cxl_mce_records, node) { + if (cur->hpa == hpa) { + list_del(&cur->node); + break; + } + } + + mutex_unlock(&cxl_mce_mutex); +} + +struct cxl_contains_hpa_context { + bool contains; + u64 hpa; +}; + +static int __cxl_contains_hpa(struct device *dev, void *arg) +{ + struct cxl_contains_hpa_context *ctx = arg; + struct cxl_endpoint_decoder *cxled; + struct range *range; + u64 hpa = ctx->hpa; + + if (!is_endpoint_decoder(dev)) + return 0; + + cxled = to_cxl_endpoint_decoder(dev); + range = &cxled->cxld.hpa_range; + + if (range->start <= hpa && hpa <= range->end) { + ctx->contains = true; + return 1; + } + + return 0; +} + +static bool cxl_contains_hpa(const struct cxl_memdev *cxlmd, u64 hpa) +{ + struct cxl_contains_hpa_context ctx = { + .contains = false, + .hpa = hpa, + }; + struct cxl_port *port; + + port = cxlmd->endpoint; + if (port && is_cxl_endpoint(port) && cxl_num_decoders_committed(port)) + device_for_each_child(&port->dev, &ctx, __cxl_contains_hpa); + + return ctx.contains; +} + +static int cxl_handle_mce(struct notifier_block *nb, unsigned long val, + void *data) +{ + struct mce *mce = (struct mce *)data; + struct cxl_memdev_state *mds = container_of(nb, struct cxl_memdev_state, + mce_notifier); + u64 hpa; + + if (!mce || !mce_usable_address(mce)) + return NOTIFY_DONE; + + hpa = mce->addr & MCI_ADDR_PHYSADDR; + + /* Check if the PFN is located on this CXL device */ + if (!pfn_valid(hpa >> PAGE_SHIFT) && + !cxl_contains_hpa(mds->cxlds.cxlmd, hpa)) + return NOTIFY_DONE; + + /* + * Search PFN in the cxl_mce_records, if already exists, don't continue + * to do memory_failure() to avoid a poison address being reported + * more than once. + */ + if (cxl_mce_recorded(hpa)) + return NOTIFY_STOP; + else + return NOTIFY_OK; +} + struct cxl_memdev_state *cxl_memdev_state_create(struct device *dev) { struct cxl_memdev_state *mds; @@ -1427,6 +1553,10 @@ struct cxl_memdev_state *cxl_memdev_state_create(struct device *dev) mds->ram_perf.qos_class = CXL_QOS_CLASS_INVALID; mds->pmem_perf.qos_class = CXL_QOS_CLASS_INVALID;+ mds->mce_notifier.notifier_call = cxl_handle_mce;+ mds->mce_notifier.priority = MCE_PRIO_CXL; + mce_register_decode_chain(&mds->mce_notifier); + return mds; } EXPORT_SYMBOL_NS_GPL(cxl_memdev_state_create, CXL); diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c index 0277726afd04..aa3ac89d17be 100644 --- a/drivers/cxl/core/memdev.c +++ b/drivers/cxl/core/memdev.c @@ -376,10 +376,14 @@ int cxl_clear_poison(struct cxl_memdev *cxlmd, u64 dpa) goto out;cxlr = cxl_dpa_to_region(cxlmd, dpa);- if (cxlr) + if (cxlr) { + u64 hpa = cxl_trace_hpa(cxlr, cxlmd, dpa); + + cxl_mce_clear(hpa); dev_warn_once(mds->cxlds.dev, "poison clear dpa:%#llx region: %s\n", dpa, dev_name(&cxlr->dev)); + }record = (struct cxl_poison_record) {.address = cpu_to_le64(dpa), diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h index 19aba81cdf13..fbf8d9f46984 100644 --- a/drivers/cxl/cxlmem.h +++ b/drivers/cxl/cxlmem.h @@ -501,6 +501,7 @@ struct cxl_memdev_state { struct cxl_fw_state fw;struct rcuwait mbox_wait;+ struct notifier_block mce_notifier; int (*mbox_send)(struct cxl_memdev_state *mds, struct cxl_mbox_cmd *cmd); }; @@ -836,6 +837,8 @@ int cxl_mem_get_poison(struct cxl_memdev *cxlmd, u64 offset, u64 len, int cxl_trigger_poison_list(struct cxl_memdev *cxlmd); int cxl_inject_poison(struct cxl_memdev *cxlmd, u64 dpa); int cxl_clear_poison(struct cxl_memdev *cxlmd, u64 dpa); +bool cxl_mce_recorded(u64 pfn); +void cxl_mce_clear(u64 pfn);#ifdef CONFIG_CXL_SUSPENDvoid cxl_mem_active_inc(void);
