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X-CSE-ConnectionGUID: I16S3jffTaOdeqYuK/vVNA== X-CSE-MsgGUID: 9I+hWnbATvqFlVCm/JJB7g== X-IronPort-AV: E=McAfee;i="6800,10657,11586"; a="63267461" X-IronPort-AV: E=Sophos;i="6.19,246,1754982000"; d="scan'208";a="63267461" Received: from fmviesa005.fm.intel.com ([10.60.135.145]) by fmvoesa108.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Oct 2025 16:44:51 -0700 X-CSE-ConnectionGUID: OylGxD/rQ3GXXJWHr2IJZw== X-CSE-MsgGUID: YVlZ3BYmSemelRPkoArJqg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.19,246,1754982000"; d="scan'208";a="188123793" Received: from schen9-mobl4.amr.corp.intel.com (HELO [10.125.108.169]) ([10.125.108.169]) by fmviesa005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Oct 2025 16:44:50 -0700 Message-ID: <4c452ff5-bcd3-4a3e-9fc1-04fb741f9e14@intel.com> Date: Tue, 21 Oct 2025 16:44:49 -0700 Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [ndctl PATCH v3 3/7] libcxl: Add poison injection support To: Ben Cheatham , nvdimm@lists.linux.dev Cc: linux-cxl@vger.kernel.org, alison.schofield@intel.com References: <20251021183124.2311-1-Benjamin.Cheatham@amd.com> <20251021183124.2311-4-Benjamin.Cheatham@amd.com> From: Dave Jiang Content-Language: en-US In-Reply-To: <20251021183124.2311-4-Benjamin.Cheatham@amd.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 10/21/25 11:31 AM, Ben Cheatham wrote: > Add a library API for clearing and injecting poison into a CXL memory > device through the CXL debugfs. > > This API will be used by the 'cxl-inject-error' and 'cxl-clear-error' > commands in later commits. > > Signed-off-by: Ben Cheatham > --- > cxl/lib/libcxl.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++ > cxl/lib/libcxl.sym | 3 +++ > cxl/libcxl.h | 3 +++ > 3 files changed, 66 insertions(+) > > diff --git a/cxl/lib/libcxl.c b/cxl/lib/libcxl.c > index 9486b0f..9d4bd80 100644 > --- a/cxl/lib/libcxl.c > +++ b/cxl/lib/libcxl.c > @@ -5019,3 +5019,63 @@ CXL_EXPORT struct cxl_cmd *cxl_cmd_new_set_alert_config(struct cxl_memdev *memde > { > return cxl_cmd_new_generic(memdev, CXL_MEM_COMMAND_ID_SET_ALERT_CONFIG); > } > + > +CXL_EXPORT bool cxl_memdev_has_poison_injection(struct cxl_memdev *memdev) > +{ > + struct cxl_ctx *ctx = memdev->ctx; > + size_t path_len; > + bool exists; > + char *path; > + > + if (!ctx->debugfs) > + return false; > + > + path_len = strlen(ctx->debugfs) + 100; > + path = calloc(path_len, sizeof(char)); > + if (!path) > + return false; > + > + snprintf(path, path_len, "%s/cxl/%s/inject_poison", ctx->debugfs, > + cxl_memdev_get_devname(memdev)); check return value > + exists = access(path, F_OK) == 0; While this works, it is more readable this way: exists = true; ... rc = access(path, F_OK); if (rc) exists = false;> + > + free(path); > + return exists; > +} > + > +static int cxl_memdev_poison_action(struct cxl_memdev *memdev, size_t dpa, > + bool clear) > +{ > + struct cxl_ctx *ctx = memdev->ctx; > + size_t path_len; > + char addr[32]; > + char *path; > + int rc; > + > + if (!ctx->debugfs) > + return -ENOENT; > + > + path_len = strlen(ctx->debugfs) + 100; > + path = calloc(path_len, sizeof(char)); > + if (!path) > + return -ENOMEM; > + > + snprintf(path, path_len, "%s/cxl/%s/%s", ctx->debugfs, > + cxl_memdev_get_devname(memdev), > + clear ? "clear_poison" : "inject_poison"); > + snprintf(addr, 32, "0x%lx\n", dpa); check return values for both snprintf() DJ > + > + rc = sysfs_write_attr(ctx, path, addr); > + free(path); > + return rc; > +} > + > +CXL_EXPORT int cxl_memdev_inject_poison(struct cxl_memdev *memdev, size_t addr) > +{ > + return cxl_memdev_poison_action(memdev, addr, false); > +} > + > +CXL_EXPORT int cxl_memdev_clear_poison(struct cxl_memdev *memdev, size_t addr) > +{ > + return cxl_memdev_poison_action(memdev, addr, true); > +} > diff --git a/cxl/lib/libcxl.sym b/cxl/lib/libcxl.sym > index 02d5119..3bce60d 100644 > --- a/cxl/lib/libcxl.sym > +++ b/cxl/lib/libcxl.sym > @@ -304,4 +304,7 @@ global: > cxl_protocol_error_get_num; > cxl_protocol_error_get_str; > cxl_dport_protocol_error_inject; > + cxl_memdev_has_poison_injection; > + cxl_memdev_inject_poison; > + cxl_memdev_clear_poison; > } LIBCXL_9; > diff --git a/cxl/libcxl.h b/cxl/libcxl.h > index 9026e05..3b51d61 100644 > --- a/cxl/libcxl.h > +++ b/cxl/libcxl.h > @@ -105,6 +105,9 @@ int cxl_memdev_read_label(struct cxl_memdev *memdev, void *buf, size_t length, > size_t offset); > int cxl_memdev_write_label(struct cxl_memdev *memdev, void *buf, size_t length, > size_t offset); > +bool cxl_memdev_has_poison_injection(struct cxl_memdev *memdev); > +int cxl_memdev_inject_poison(struct cxl_memdev *memdev, size_t dpa); > +int cxl_memdev_clear_poison(struct cxl_memdev *memdev, size_t dpa); > struct cxl_cmd *cxl_cmd_new_get_fw_info(struct cxl_memdev *memdev); > unsigned int cxl_cmd_fw_info_get_num_slots(struct cxl_cmd *cmd); > unsigned int cxl_cmd_fw_info_get_active_slot(struct cxl_cmd *cmd);