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Message-ID: <20231219143732.0000181e@Huawei.com>
Date: Tue, 19 Dec 2023 14:37:32 +0000
From: Jonathan Cameron <Jonathan.Cameron@...wei.com>
To: Ira Weiny <ira.weiny@...el.com>
CC: Dan Williams <dan.j.williams@...el.com>, Smita Koralahalli
<Smita.KoralahalliChannabasappa@....com>, Shiju Jose <shiju.jose@...wei.com>,
Yazen Ghannam <yazen.ghannam@....com>, "Davidlohr Bueso" <dave@...olabs.net>,
Dave Jiang <dave.jiang@...el.com>, "Alison Schofield"
<alison.schofield@...el.com>, Vishal Verma <vishal.l.verma@...el.com>, Ard
Biesheuvel <ardb@...nel.org>, <linux-efi@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <linux-cxl@...r.kernel.org>, Bjorn Helgaas
<bhelgaas@...gle.com>
Subject: Re: [PATCH v4 7/7] cxl/memdev: Register for and process CPER events
On Fri, 15 Dec 2023 15:26:33 -0800
Ira Weiny <ira.weiny@...el.com> wrote:
> If the firmware has configured CXL event support to be firmware first
> the OS can process those events through CPER records. The CXL layer has
> unique DPA to HPA knowledge and standard event trace parsing in place.
>
> CPER records contain Bus, Device, Function information which can be used
> to identify the PCI device which is sending the event.
>
> Change pci driver registration to include registration for a CXL CPER
> notifier to process the events through the trace subsystem.
>
> Define and use scoped based management to simplify the handling of the
> pci device object.
>
> Cc: Bjorn Helgaas <bhelgaas@...gle.com>
> Signed-off-by: Ira Weiny <ira.weiny@...el.com>
I'd break out the pci guard stuff as a precursor patch. That's likely
to be used elsewhere so it would help for backporting for other users
if it wasn't buried in a patch doing other stuff.
Not to mention that has a different set of likely reviewers to the rest
of this patch.
More generally maybe we should just hardcode the UUID in the tracepoint
definitions? I think for everything other than the generic one we
only ever call trace_cxl_memory_module(... &mem_mod_event_uuid..)
etc.
It's a little ugly to match on the UUID to call a function where it
hard coded, but less so than inserting the UUID like this does.
Better I think to make it obvious that this isn't actually a variable
(for the ones we understand).
Jonathan
>
> ---
> NOTE this patch depends on Dan's addition of a device guard[1].
>
> [1] https://lore.kernel.org/all/170250854466.1522182.17555361077409628655.stgit@dwillia2-xfh.jf.intel.com/
>
> Changes for v3/v4:
> [djbw: define a __free(pci_dev_put) to release the device automatically]
> [djbw: use device guard from Vishal]
> [iweiny: delete old notifier block structure]
> [iweiny: adjust for new notifier interface]
> ---
> drivers/cxl/core/mbox.c | 31 +++++++++++++++++++++++-----
> drivers/cxl/cxlmem.h | 4 ++++
> drivers/cxl/pci.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++-
> include/linux/pci.h | 2 ++
> 4 files changed, 86 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
> index b7efa058a100..c9aa723e3391 100644
> --- a/drivers/cxl/core/mbox.c
> +++ b/drivers/cxl/core/mbox.c
> @@ -840,9 +840,30 @@ static const uuid_t gen_media_event_uuid = CXL_EVENT_GEN_MEDIA_UUID;
> static const uuid_t dram_event_uuid = CXL_EVENT_DRAM_UUID;
> static const uuid_t mem_mod_event_uuid = CXL_EVENT_MEM_MODULE_UUID;
>
> -static void cxl_event_trace_record(const struct cxl_memdev *cxlmd,
> - enum cxl_event_log_type type,
> - struct cxl_event_record_raw *record)
> +void cxl_event_trace_record(const struct cxl_memdev *cxlmd,
> + enum cxl_event_log_type type,
> + enum cxl_event_type event_type,
> + union cxl_event *event)
> +{
> + switch (event_type) {
> + case CXL_CPER_EVENT_GEN_MEDIA:
> + trace_cxl_general_media(cxlmd, type, &gen_media_event_uuid,
> + &event->gen_media);
> + break;
> + case CXL_CPER_EVENT_DRAM:
> + trace_cxl_dram(cxlmd, type, &dram_event_uuid, &event->dram);
> + break;
> + case CXL_CPER_EVENT_MEM_MODULE:
> + trace_cxl_memory_module(cxlmd, type, &mem_mod_event_uuid,
> + &event->mem_module);
> + break;
> + }
> +}
> +EXPORT_SYMBOL_NS_GPL(cxl_event_trace_record, CXL);
> +
> +static void __cxl_event_trace_record(const struct cxl_memdev *cxlmd,
> + enum cxl_event_log_type type,
> + struct cxl_event_record_raw *record)
> {
> union cxl_event *evt = &record->event;
> uuid_t *id = &record->id;
> @@ -965,8 +986,8 @@ static void cxl_mem_get_records_log(struct cxl_memdev_state *mds,
> break;
>
> for (i = 0; i < nr_rec; i++)
> - cxl_event_trace_record(cxlmd, type,
> - &payload->records[i]);
> + __cxl_event_trace_record(cxlmd, type,
> + &payload->records[i]);
>
> if (payload->flags & CXL_GET_EVENT_FLAG_OVERFLOW)
> trace_cxl_overflow(cxlmd, type, payload);
> diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
> index 0155fb66b580..638275569d63 100644
> --- a/drivers/cxl/pci.c
> +++ b/drivers/cxl/pci.c
> @@ -1,5 +1,6 @@
> // SPDX-License-Identifier: GPL-2.0-only
> /* Copyright(c) 2020 Intel Corporation. All rights reserved. */
> +#include <asm-generic/unaligned.h>
> #include <linux/io-64-nonatomic-lo-hi.h>
> #include <linux/moduleparam.h>
> #include <linux/module.h>
> @@ -969,6 +970,58 @@ static struct pci_driver cxl_pci_driver = {
> },
> };
>
> +#define CXL_EVENT_HDR_FLAGS_REC_SEVERITY GENMASK(1, 0)
> +static void cxl_cper_event_call(enum cxl_event_type ev_type,
> + struct cxl_cper_event_rec *rec)
> +{
> + struct cper_cxl_event_devid *device_id = &rec->hdr.device_id;
> + struct pci_dev *pdev __free(pci_dev_put) = NULL;
> + struct cxl_dev_state *cxlds = NULL;
> + enum cxl_event_log_type log_type;
> + unsigned int devfn;
> + u32 hdr_flags;
> +
> + devfn = PCI_DEVFN(device_id->device_num, device_id->func_num);
> + pdev = pci_get_domain_bus_and_slot(device_id->segment_num,
> + device_id->bus_num, devfn);
> + if (!pdev)
> + return;
> +
> + guard(device)(&pdev->dev);
> + if (pdev->driver == &cxl_pci_driver)
> + cxlds = pci_get_drvdata(pdev);
> + if (!cxlds)
> + return;
This is handling two conditions. I'd find it more readable split like:
if (pdev->driver != &cxl_pci_driver)
return;
cxlds = pci_get_drvdata(pdev);
if (!cxlds)
return;
and drop the = NULL above.
> +
> + /* Fabricate a log type */
> + hdr_flags = get_unaligned_le24(rec->event.generic.hdr.flags);
> + log_type = FIELD_GET(CXL_EVENT_HDR_FLAGS_REC_SEVERITY, hdr_flags);
> +
> + cxl_event_trace_record(cxlds->cxlmd, log_type, ev_type, &rec->event);
> +}
> +
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