On 6/18/24 9:53 AM, Shiyang Ruan 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_e8be29...@dwillia2-mobl3.amr.corp.intel.com.notmuch/
>
> Signed-off-by: Shiyang Ruan <ruansy.f...@fujitsu.com>
> ---
> 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);
> + 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);
> + 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))
Maybe no need to check is_cxl_endpoint() if the port is retrieved from
cxlmd->endpoint.
Also, in order to use cxl_num_decoders_committed(), cxl_region_rwsem must be
held. See the lockdep_assert_held() in the function. Maybe add a
guard(cxl_regoin_rwsem);
before the if statement above.
DJ
> + 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_SUSPEND
> void cxl_mem_active_inc(void);
