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Message-ID: <20220616194334.pvorvoozt4rrzr66@offworld>
Date: Thu, 16 Jun 2022 12:43:34 -0700
From: Davidlohr Bueso <dave@...olabs.net>
To: "alison.schofield@...el.com" <alison.schofield@...el.com>
Cc: Dan Williams <dan.j.williams@...el.com>,
Ira Weiny <ira.weiny@...el.com>,
Vishal Verma <vishal.l.verma@...el.com>,
Ben Widawsky <bwidawsk@...nel.org>,
Steven Rostedt <rostedt@...dmis.org>,
Ingo Molnar <mingo@...hat.com>, linux-cxl@...r.kernel.org,
linux-kernel@...r.kernel.org, a.manzanares@...sung.com
Subject: Re: [PATCH 2/3] cxl/mbox: Add GET_POISON_LIST mailbox command support
On Tue, 14 Jun 2022, alison.schofield@...el.com wrote:
>From: Alison Schofield <alison.schofield@...el.com>
>
>CXL devices that support persistent memory maintain a list of locations
>that are poisoned or result in poison if the addresses are accessed by
>the host.
>
>Per the spec (CXL 2.0 8.2.8.5.4.1), the device returns this Poison
>list as a set of Media Error Records that include the source of the
>error, the starting device physical address and length. The length is
>the number of adjacent DPAs in the record and is in units of 64 bytes.
>
>Retrieve the list and log each Media Error Record as a trace event of
>type cxl_poison_list.
>
>Signed-off-by: Alison Schofield <alison.schofield@...el.com>
>---
> drivers/cxl/cxlmem.h | 43 +++++++++++++++++++++++
> drivers/cxl/core/mbox.c | 75 +++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 118 insertions(+)
>
>diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
>index 60d10ee1e7fc..29cf0459b44a 100644
>--- a/drivers/cxl/cxlmem.h
>+++ b/drivers/cxl/cxlmem.h
>@@ -174,6 +174,7 @@ struct cxl_endpoint_dvsec_info {
> * (CXL 2.0 8.2.8.4.3 Mailbox Capabilities Register)
> * @lsa_size: Size of Label Storage Area
> * (CXL 2.0 8.2.9.5.1.1 Identify Memory Device)
>+ * @poison_max_mer: maximum Media Error Records tracked in Poison List
> * @mbox_mutex: Mutex to synchronize mailbox access.
> * @firmware_version: Firmware version for the memory device.
> * @enabled_cmds: Hardware commands found enabled in CEL.
>@@ -204,6 +205,7 @@ struct cxl_dev_state {
>
> size_t payload_size;
> size_t lsa_size;
>+ u32 poison_max;
> struct mutex mbox_mutex; /* Protects device mailbox and firmware */
> char firmware_version[0x10];
> DECLARE_BITMAP(enabled_cmds, CXL_MEM_COMMAND_ID_MAX);
>@@ -317,6 +319,46 @@ struct cxl_mbox_set_partition_info {
>
> #define CXL_SET_PARTITION_IMMEDIATE_FLAG BIT(0)
>
>+struct cxl_mbox_poison_payload_in {
>+ __le64 offset;
>+ __le64 length;
>+} __packed;
>+
>+struct cxl_mbox_poison_payload_out {
>+ u8 flags;
>+ u8 rsvd1;
>+ __le64 overflow_timestamp;
>+ __le16 count;
>+ u8 rsvd2[0x14];
>+ struct cxl_poison_record {
>+ __le64 address;
>+ __le32 length;
>+ __le32 rsvd;
>+ } __packed record[];
>+} __packed;
>+
>+/* CXL 8.2.9.5.4.1 Get Poison List: payload out flags: */
>+#define CXL_POISON_FLAG_MORE BIT(0)
>+#define CXL_POISON_FLAG_OVERFLOW BIT(1)
>+#define CXL_POISON_FLAG_SCANNING BIT(2)
>+
>+/* CXL 8.2.9.5.4.1 Get Poison List: Error is encoded in record.address[2:0] */
>+#define CXL_POISON_SOURCE_MASK GENMASK(2, 0)
>+#define CXL_POISON_SOURCE_UNKNOWN 0
>+#define CXL_POISON_SOURCE_EXTERNAL 1
>+#define CXL_POISON_SOURCE_INTERNAL 2
>+#define CXL_POISON_SOURCE_INJECTED 3
>+#define CXL_POISON_SOURCE_VENDOR 7
>+
>+/* Software define */
>+#define CXL_POISON_SOURCE_INVALID 99
>+#define CXL_POISON_SOURCE_VALID(x) \
>+ (((x) == CXL_POISON_SOURCE_UNKNOWN) || \
>+ ((x) == CXL_POISON_SOURCE_EXTERNAL) || \
>+ ((x) == CXL_POISON_SOURCE_INTERNAL) || \
>+ ((x) == CXL_POISON_SOURCE_INJECTED) || \
>+ ((x) == CXL_POISON_SOURCE_VENDOR))
>+
> /**
> * struct cxl_mem_command - Driver representation of a memory device command
> * @info: Command information as it exists for the UAPI
>@@ -351,6 +393,7 @@ int cxl_mem_create_range_info(struct cxl_dev_state *cxlds);
> struct cxl_dev_state *cxl_dev_state_create(struct device *dev);
> void set_exclusive_cxl_commands(struct cxl_dev_state *cxlds, unsigned long *cmds);
> void clear_exclusive_cxl_commands(struct cxl_dev_state *cxlds, unsigned long *cmds);
>+int cxl_mem_get_poison_list(struct device *dev);
> #ifdef CONFIG_CXL_SUSPEND
> void cxl_mem_active_inc(void);
> void cxl_mem_active_dec(void);
>diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
>index 54f434733b56..c10c7020ebc2 100644
>--- a/drivers/cxl/core/mbox.c
>+++ b/drivers/cxl/core/mbox.c
>@@ -9,6 +9,9 @@
>
> #include "core.h"
>
>+#define CREATE_TRACE_POINTS
>+#include <trace/events/cxl.h>
>+
> static bool cxl_raw_allow_all;
>
> /**
>@@ -755,6 +758,7 @@ int cxl_dev_state_identify(struct cxl_dev_state *cxlds)
> {
> /* See CXL 2.0 Table 175 Identify Memory Device Output Payload */
> struct cxl_mbox_identify id;
>+ __le32 val = 0;
> int rc;
>
> rc = cxl_mbox_send_cmd(cxlds, CXL_MBOX_OP_IDENTIFY, NULL, 0, &id,
>@@ -783,6 +787,9 @@ int cxl_dev_state_identify(struct cxl_dev_state *cxlds)
> cxlds->lsa_size = le32_to_cpu(id.lsa_size);
> memcpy(cxlds->firmware_version, id.fw_revision, sizeof(id.fw_revision));
>
>+ memcpy(&val, id.poison_list_max_mer, 3);
>+ cxlds->poison_max = le32_to_cpu(val);
>+
> return 0;
> }
> EXPORT_SYMBOL_NS_GPL(cxl_dev_state_identify, CXL);
>@@ -826,6 +833,74 @@ int cxl_mem_create_range_info(struct cxl_dev_state *cxlds)
> }
> EXPORT_SYMBOL_NS_GPL(cxl_mem_create_range_info, CXL);
>
>+int cxl_mem_get_poison_list(struct device *dev)
>+{
>+ struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
>+ struct cxl_dev_state *cxlds = cxlmd->cxlds;
>+ struct cxl_mbox_poison_payload_out *po;
>+ struct cxl_mbox_poison_payload_in pi;
>+ int nr_records = 0;
>+ int rc, i;
>+
>+ if (range_len(&cxlds->pmem_range)) {
>+ pi.offset = cpu_to_le64(cxlds->pmem_range.start);
>+ pi.length = cpu_to_le64(range_len(&cxlds->pmem_range));
Do you ever see this changing to not always use the full pmem DPA range
but allow arbitrary ones? I also assume this is the reason why you don't
check the range vs cxlds->ram_range to prevent any overlaps, no?
Thanks,
Davidlohr
>+ } else {
>+ return -ENXIO;
>+ }
>+
>+ po = kvmalloc(cxlds->payload_size, GFP_KERNEL);
>+ if (!po)
>+ return -ENOMEM;
>+
>+ do {
>+ rc = cxl_mbox_send_cmd(cxlds, CXL_MBOX_OP_GET_POISON, &pi,
>+ sizeof(pi), po, cxlds->payload_size);
>+ if (rc)
>+ goto out;
>+
>+ if (po->flags & CXL_POISON_FLAG_OVERFLOW) {
>+ time64_t o_time = le64_to_cpu(po->overflow_timestamp);
>+
>+ dev_err(dev, "Poison list overflow at %ptTs UTC\n",
>+ &o_time);
>+ rc = -ENXIO;
>+ goto out;
>+ }
>+
>+ if (po->flags & CXL_POISON_FLAG_SCANNING) {
>+ dev_err(dev, "Scan Media in Progress\n");
>+ rc = -EBUSY;
>+ goto out;
>+ }
>+
>+ for (i = 0; i < le16_to_cpu(po->count); i++) {
>+ u64 addr = le64_to_cpu(po->record[i].address);
>+ u32 len = le32_to_cpu(po->record[i].length);
>+ int source = FIELD_GET(CXL_POISON_SOURCE_MASK, addr);
>+
>+ if (!CXL_POISON_SOURCE_VALID(source)) {
>+ dev_dbg(dev, "Invalid poison source %d",
>+ source);
>+ source = CXL_POISON_SOURCE_INVALID;
>+ }
>+
>+ trace_cxl_poison_list(dev, source, addr, len);
>+ }
>+
>+ /* Protect against an uncleared _FLAG_MORE */
>+ nr_records = nr_records + le16_to_cpu(po->count);
>+ if (nr_records >= cxlds->poison_max)
>+ goto out;
>+
>+ } while (po->flags & CXL_POISON_FLAG_MORE);
>+
>+out:
>+ kvfree(po);
>+ return rc;
>+}
>+EXPORT_SYMBOL_NS_GPL(cxl_mem_get_poison_list, CXL);
>+
> struct cxl_dev_state *cxl_dev_state_create(struct device *dev)
> {
> struct cxl_dev_state *cxlds;
>
>--
>2.31.1
>
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