Hi Davidlohr,
Thanks for reviewing and comments.
>-----Original Message-----
>From: Davidlohr Bueso <dave@xxxxxxxxxxxx>
>Sent: 22 November 2023 00:22
>To: Shiju Jose <shiju.jose@xxxxxxxxxx>
>Cc: linux-cxl@xxxxxxxxxxxxxxx; linux-mm@xxxxxxxxx; Jonathan Cameron
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>Subject: Re: [PATCH v2 04/10] cxl/memscrub: Add CXL device patrol scrub
>control feature
>
>On Tue, 21 Nov 2023, shiju.jose@xxxxxxxxxx wrote:
>
>>From: Shiju Jose <shiju.jose@xxxxxxxxxx>
>>
>>CXL spec 3.1 section 8.2.9.9.11.1 describes the device patrol scrub
>>control feature. The device patrol scrub proactively locates and makes
>>corrections to errors in regular cycle. The patrol scrub control allows
>>the request to configure patrol scrub input configurations.
>>
>>The patrol scrub control allows the requester to specify the number of
>>hours for which the patrol scrub cycles must be completed, provided
>>that the requested number is not less than the minimum number of hours
>>for the patrol scrub cycle that the device is capable of. In addition,
>>the patrol scrub controls allow the host to disable and enable the
>>feature in case disabling of the feature is needed for other purposes
>>such as performance-aware operations which require the background
>>operations to be turned off.
>>
>>Signed-off-by: Shiju Jose <shiju.jose@xxxxxxxxxx>
>>---
>> drivers/cxl/Kconfig | 17 +++
>> drivers/cxl/core/Makefile | 1 +
>> drivers/cxl/core/memscrub.c | 272
>++++++++++++++++++++++++++++++++++++
>> drivers/cxl/cxlmem.h | 8 ++
>> drivers/cxl/pci.c | 6 +
>> 5 files changed, 304 insertions(+)
>> create mode 100644 drivers/cxl/core/memscrub.c
>>
>>diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig index
>>8ea1d340e438..e91f5acc94f2 100644
>>--- a/drivers/cxl/Kconfig
>>+++ b/drivers/cxl/Kconfig
>>@@ -154,4 +154,21 @@ config CXL_PMU
>> monitoring units and provide standard perf based interfaces.
>>
>> If unsure say 'm'.
>>+
>>+config CXL_SCRUB
>>+ tristate "CXL: Memory scrub feature"
>>+ depends on CXL_PCI
>>+ depends on CXL_MEM
>>+ help
>>+ The CXL memory scrub control is an optional feature allows host to
>>+ control the scrub configurations of CXL Type 3 devices, which
>>+ support patrol scrub and/or DDR5 ECS(Error Check Scrub).
>>+
>>+ Say 'y/m' to enable the CXL memory scrub driver that will attach to
>>+ CXL.mem devices for memory scrub control feature. See sections
>>+ 8.2.9.9.11.1 and 8.2.9.9.11.2 in the CXL 3.1 specification for a
>>+ detailed description of CXL memory scrub control features.
>>+
>>+ If unsure say 'm'.
>
>Does this really warrant yet another kconfig option?
I missed to change 'm' -> 'n' and tristate->bool.
>
>>+
>> endif
>>diff --git a/drivers/cxl/core/Makefile b/drivers/cxl/core/Makefile
>>index 1f66b5d4d935..99e3202f868f 100644
>>--- a/drivers/cxl/core/Makefile
>>+++ b/drivers/cxl/core/Makefile
>>@@ -15,3 +15,4 @@ cxl_core-y += hdm.o
>> cxl_core-y += pmu.o
>> cxl_core-$(CONFIG_TRACING) += trace.o
>> cxl_core-$(CONFIG_CXL_REGION) += region.o
>>+cxl_core-$(CONFIG_CXL_SCRUB) += memscrub.o
>>diff --git a/drivers/cxl/core/memscrub.c b/drivers/cxl/core/memscrub.c
>>new file mode 100644 index 000000000000..7d98a1593abe
>>--- /dev/null
>>+++ b/drivers/cxl/core/memscrub.c
>>@@ -0,0 +1,272 @@
>>+// SPDX-License-Identifier: GPL-2.0-or-later
>>+/*
>>+ * cxl_memscrub.c - CXL memory scrub driver
>>+ *
>>+ * Copyright (c) 2023 HiSilicon Limited.
>>+ *
>>+ * - Provides functions to configure patrol scrub
>>+ * feature of the CXL memory devices.
>>+ */
>>+
>>+#define pr_fmt(fmt) "CXL_MEM_SCRUB: " fmt
>>+
>>+#include <cxlmem.h>
>>+
>>+/* CXL memory scrub feature common definitions */
>>+#define CXL_SCRUB_MAX_ATTRB_RANGE_LENGTH 128
>>+
>>+static int cxl_mem_get_supported_feature_entry(struct cxl_memdev *cxlmd,
>const uuid_t *feat_uuid,
>>+ struct cxl_mbox_supp_feat_entry
>*feat_entry_out)
>
>It would be nicer if the feat_entry_out pointer was returned instead of passed by
>parameter.
The memory for the feats_out would be freed when exit cxl_mem_get_supported_feature_entry(),
thus feats_out->feat_entries is invalid outside. Hence copying the requested feat_entry data to the
feat_entry_out pointer passed.
>
>>+{
>>+ struct cxl_mbox_get_supp_feats_out *feats_out __free(kvfree) = NULL;
>>+ struct cxl_mbox_supp_feat_entry *feat_entry;
>>+ struct cxl_dev_state *cxlds = cxlmd->cxlds;
>>+ struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
>>+ struct cxl_mbox_get_supp_feats_in pi;
>>+ bool is_support_feature = false;
>>+ int feat_index, count;
>>+ int nentries;
>>+ int ret;
>>+
>>+ feat_index = 0;
>>+ pi.count = sizeof(struct cxl_mbox_get_supp_feats_out) +
>>+ sizeof(struct cxl_mbox_supp_feat_entry);
>>+ feats_out = kvmalloc(pi.count, GFP_KERNEL);
>>+ if (!feats_out)
>>+ return -ENOMEM;
>>+
>>+ do {
>>+ pi.start_index = feat_index;
>>+ memset(feats_out, 0, pi.count);
>>+ ret = cxl_get_supported_features(mds, &pi, feats_out);
>>+ if (ret)
>>+ return ret;
>>+
>>+ nentries = feats_out->entries;
>>+ if (!nentries)
>>+ break;
>>+
>>+ /* Check CXL memdev supports the feature */
>>+ feat_entry = (void *)feats_out->feat_entries;
>>+ for (count = 0; count < nentries; count++, feat_entry++) {
>>+ if (uuid_equal(&feat_entry->uuid, feat_uuid)) {
>>+ is_support_feature = true;
>>+ memcpy(feat_entry_out, feat_entry,
>sizeof(*feat_entry_out));
>>+ break;
>
>Just return 0 in this case, and then you can do without the is_supported_feature
>flag.
Sure.
>
>>+ }
>>+ }
>>+ if (is_support_feature)
>>+ break;
>>+ feat_index += nentries;
>>+ } while (nentries);
>>+
>>+ if (!is_support_feature)
>>+ return -ENOTSUPP;
>>+
>>+ return 0;
>>+}
>>+
>>+/* CXL memory patrol scrub control definitions */
>>+#define CXL_MEMDEV_PS_GET_FEAT_VERSION 0x01
>>+#define CXL_MEMDEV_PS_SET_FEAT_VERSION 0x01
>>+
>>+static const uuid_t cxl_patrol_scrub_uuid =
>>+ UUID_INIT(0x96dad7d6, 0xfde8, 0x482b, 0xa7, 0x33, 0x75, 0x77, 0x4e,
>\
>>+ 0x06, 0xdb, 0x8a);
>>+
>>+/* CXL memory patrol scrub control functions */ struct
>>+cxl_patrol_scrub_context {
>>+ struct device *dev;
>>+ u16 get_feat_size;
>>+ u16 set_feat_size;
>>+ bool scrub_cycle_changable;
>
>s/changable/changeable
Ok.
>
>>+};
>>+
>>+/**
>>+ * struct cxl_memdev_ps_params - CXL memory patrol scrub parameter data
>structure.
>>+ * @enable: [IN] enable(1)/disable(0) patrol scrub.
>>+ * @scrub_cycle_changable: [OUT] scrub cycle attribute of patrol scrub is
>changeable.
>>+ * @speed: [IN] Requested patrol scrub cycle in hours.
>>+ * [OUT] Current patrol scrub cycle in hours.
>>+ * @min_speed:[OUT] minimum patrol scrub cycle, in hours, supported.
>>+ * @speed_avail:[OUT] Supported patrol scrub cycle in hours.
>>+ */
>>+struct cxl_memdev_ps_params {
>>+ bool enable;
>>+ bool scrub_cycle_changable;
>>+ u16 speed;
>>+ u16 min_speed;
>>+ char speed_avail[CXL_SCRUB_MAX_ATTRB_RANGE_LENGTH];
>>+};
>>+
>>+enum {
>>+ CXL_MEMDEV_PS_PARAM_ENABLE = 0,
>>+ CXL_MEMDEV_PS_PARAM_SPEED,
>>+};
>>+
>>+#define CXL_MEMDEV_PS_SCRUB_CYCLE_CHANGE_CAP_MASK BIT(0)
>>+#define
> CXL_MEMDEV_PS_SCRUB_CYCLE_REALTIME_REPORT_CAP_MASK
> BIT(1)
>>+#define CXL_MEMDEV_PS_CUR_SCRUB_CYCLE_MASK GENMASK(7, 0)
>>+#define CXL_MEMDEV_PS_MIN_SCRUB_CYCLE_MASK GENMASK(15,
>8)
>>+#define CXL_MEMDEV_PS_FLAG_ENABLED_MASK BIT(0)
>>+
>>+struct cxl_memdev_ps_feat_read_attrbs {
>>+ u8 scrub_cycle_cap;
>>+ __le16 scrub_cycle;
>>+ u8 scrub_flags;
>>+} __packed;
>>+
>>+struct cxl_memdev_ps_set_feat_pi {
>>+ struct cxl_mbox_set_feat_in pi;
>>+ u8 scrub_cycle_hr;
>>+ u8 scrub_flags;
>>+} __packed;
>>+
>>+static int cxl_mem_ps_get_attrbs(struct device *dev,
>>+ struct cxl_memdev_ps_params *params) {
>>+ struct cxl_memdev_ps_feat_read_attrbs *rd_attrbs __free(kvfree) =
>NULL;
>>+ struct cxl_mbox_get_feat_in pi = {
>>+ .uuid = cxl_patrol_scrub_uuid,
>>+ .offset = 0,
>>+ .count = sizeof(struct cxl_memdev_ps_feat_read_attrbs),
>>+ .selection = CXL_GET_FEAT_SEL_CURRENT_VALUE,
>>+ };
>>+ struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
>>+ struct cxl_dev_state *cxlds = cxlmd->cxlds;
>>+ struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
>>+ int ret;
>>+
>>+ if (!mds)
>>+ return -EFAULT;
>>+
>>+ rd_attrbs = kvmalloc(pi.count, GFP_KERNEL);
>>+ if (!rd_attrbs)
>>+ return -ENOMEM;
>>+
>>+ ret = cxl_get_feature(mds, &pi, rd_attrbs);
>>+ if (ret) {
>>+ params->enable = 0;
>>+ params->speed = 0;
>>+ snprintf(params->speed_avail,
>CXL_SCRUB_MAX_ATTRB_RANGE_LENGTH,
>>+ "Unavailable");
>>+ return ret;
>>+ }
>>+ params->scrub_cycle_changable =
>FIELD_GET(CXL_MEMDEV_PS_SCRUB_CYCLE_CHANGE_CAP_MASK,
>>+ rd_attrbs->scrub_cycle_cap);
>>+ params->enable =
>FIELD_GET(CXL_MEMDEV_PS_FLAG_ENABLED_MASK,
>>+ rd_attrbs->scrub_flags);
>>+ params->speed =
>FIELD_GET(CXL_MEMDEV_PS_CUR_SCRUB_CYCLE_MASK,
>>+ rd_attrbs->scrub_cycle);
>>+ params->min_speed =
>FIELD_GET(CXL_MEMDEV_PS_MIN_SCRUB_CYCLE_MASK,
>>+ rd_attrbs->scrub_cycle);
>>+ snprintf(params->speed_avail,
>CXL_SCRUB_MAX_ATTRB_RANGE_LENGTH,
>>+ "Minimum scrub cycle = %d hour", params->min_speed);
>>+
>>+ return 0;
>>+}
>>+
>>+static int cxl_mem_ps_set_attrbs(struct device *dev,
>>+ struct cxl_memdev_ps_params *params, u8
>param_type) {
>>+ struct cxl_memdev_ps_set_feat_pi set_pi = {
>>+ .pi.uuid = cxl_patrol_scrub_uuid,
>>+ .pi.flags =
>CXL_SET_FEAT_FLAG_MOD_VALUE_SAVED_ACROSS_RESET |
>>+ CXL_SET_FEAT_FLAG_FULL_DATA_TRANSFER,
>>+ .pi.offset = 0,
>>+ .pi.version = CXL_MEMDEV_PS_SET_FEAT_VERSION,
>>+ };
>>+ struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
>>+ struct cxl_dev_state *cxlds = cxlmd->cxlds;
>>+ struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
>>+ struct cxl_memdev_ps_params rd_params;
>>+ int ret;
>>+
>>+ if (!mds)
>>+ return -EFAULT;
>>+
>>+ ret = cxl_mem_ps_get_attrbs(dev, &rd_params);
>>+ if (ret) {
>>+ dev_err(dev, "Get cxlmemdev patrol scrub params fail
>ret=%d\n",
>>+ ret);
>>+ return ret;
>>+ }
>>+
>>+ switch (param_type) {
>>+ case CXL_MEMDEV_PS_PARAM_ENABLE:
>>+ set_pi.scrub_flags =
>FIELD_PREP(CXL_MEMDEV_PS_FLAG_ENABLED_MASK,
>>+ params->enable);
>>+ set_pi.scrub_cycle_hr =
>FIELD_PREP(CXL_MEMDEV_PS_CUR_SCRUB_CYCLE_MASK,
>>+ rd_params.speed);
>>+ break;
>>+ case CXL_MEMDEV_PS_PARAM_SPEED:
>>+ if (params->speed < rd_params.min_speed) {
>>+ dev_err(dev, "Invalid CXL patrol scrub cycle(%d) to
>set\n",
>>+ params->speed);
>>+ dev_err(dev, "Minimum supported CXL patrol scrub
>cycle in hour %d\n",
>>+ params->min_speed);
>>+ return -EINVAL;
>>+ }
>>+ set_pi.scrub_cycle_hr =
>FIELD_PREP(CXL_MEMDEV_PS_CUR_SCRUB_CYCLE_MASK,
>>+ params->speed);
>>+ set_pi.scrub_flags =
>FIELD_PREP(CXL_MEMDEV_PS_FLAG_ENABLED_MASK,
>>+ rd_params.enable);
>>+ break;
>>+ default:
>>+ dev_err(dev, "Invalid CXL patrol scrub parameter to set\n");
>>+ return -EINVAL;
>>+ }
>>+
>>+ ret = cxl_set_feature(mds, &set_pi, sizeof(set_pi));
>>+ if (ret) {
>>+ dev_err(dev, "CXL patrol scrub set feature fail ret=%d\n",
>>+ ret);
>>+ return ret;
>>+ }
>>+
>>+ /* Verify attribute set successfully */
>>+ if (param_type == CXL_MEMDEV_PS_PARAM_SPEED) {
>>+ ret = cxl_mem_ps_get_attrbs(dev, &rd_params);
>>+ if (ret) {
>>+ dev_err(dev, "Get cxlmemdev patrol scrub params fail
>ret=%d\n", ret);
>>+ return ret;
>>+ }
>>+ if (rd_params.speed != params->speed)
>>+ return -EFAULT;
>>+ }
>>+
>>+ return 0;
>>+}
>>+
>>+int cxl_mem_patrol_scrub_init(struct cxl_memdev *cxlmd) {
>>+ struct cxl_patrol_scrub_context *cxl_ps_ctx;
>>+ struct cxl_mbox_supp_feat_entry feat_entry;
>>+ struct cxl_memdev_ps_params params;
>>+ int ret;
>>+
>>+ ret = cxl_mem_get_supported_feature_entry(cxlmd,
>&cxl_patrol_scrub_uuid,
>>+ &feat_entry);
>>+ if (ret < 0)
>>+ return ret;
>>+
>>+ if (!(feat_entry.attrb_flags & CXL_FEAT_ENTRY_FLAG_CHANGABLE))
>>+ return -ENOTSUPP;
>>+
>>+ cxl_ps_ctx = devm_kzalloc(&cxlmd->dev, sizeof(*cxl_ps_ctx),
>GFP_KERNEL);
>>+ if (!cxl_ps_ctx)
>>+ return -ENOMEM;
>>+
>>+ cxl_ps_ctx->get_feat_size = feat_entry.get_feat_size;
>>+ cxl_ps_ctx->set_feat_size = feat_entry.set_feat_size;
>>+ ret = cxl_mem_ps_get_attrbs(&cxlmd->dev, ¶ms);
>>+ if (ret) {
>>+ dev_err(&cxlmd->dev, "Get CXL patrol scrub params fail
>ret=%d\n",
>>+ ret);
>>+ return ret;
>>+ }
>>+ cxl_ps_ctx->scrub_cycle_changable = params.scrub_cycle_changable;
>>+
>>+ return 0;
>>+}
>>+EXPORT_SYMBOL_NS_GPL(cxl_mem_patrol_scrub_init, CXL);
>>diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h index
>>46131dcd0900..25c46e72af16 100644
>>--- a/drivers/cxl/cxlmem.h
>>+++ b/drivers/cxl/cxlmem.h
>>@@ -983,6 +983,14 @@ 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);
>>
>>+/* cxl memory scrub functions */
>>+#ifdef CONFIG_CXL_SCRUB
>>+int cxl_mem_patrol_scrub_init(struct cxl_memdev *cxlmd); #else static
>>+inline int cxl_mem_patrol_scrub_init(struct cxl_memdev *cxlmd) {
>>+return -ENOTSUPP; } #endif
>>+
>> #ifdef CONFIG_CXL_SUSPEND
>> void cxl_mem_active_inc(void);
>> void cxl_mem_active_dec(void);
>>diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c index
>>0155fb66b580..86bba8794bb4 100644
>>--- a/drivers/cxl/pci.c
>>+++ b/drivers/cxl/pci.c
>>@@ -881,6 +881,12 @@ static int cxl_pci_probe(struct pci_dev *pdev, const
>struct pci_device_id *id)
>> if (rc)
>> return rc;
>>
>>+ /*
>>+ * Initialize optional CXL scrub features
>>+ */
>>+ if (cxl_mem_patrol_scrub_init(cxlmd))
>>+ dev_dbg(&pdev->dev, "cxl_mem_patrol_scrub_init failed\n");
>
>Unnecessary debug msg.
Will remove.
>
>>+
>> rc = devm_cxl_sanitize_setup_notifier(&pdev->dev, cxlmd);
>> if (rc)
>> return rc;
>>--
>>2.34.1
>>
Thanks,
Shiju
