cxl/memdev: Warn of poison inject or clear to a mapped region

Inject and clear poison capabilities and intended for debug usage only.
In order to be useful in debug environments, the driver needs to allow
inject and clear operations on DPAs mapped in regions.

dev_warn_once() when either operation occurs.

Signed-off-by: Alison Schofield <alison.schofield@intel.com>
Link: https://lore.kernel.org/r/f911ca5277c9d0f9757b72d7e6842871bfff4fa2.1681874357.git.alison.schofield@intel.com
Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Author: AlisonSchofield

drivers/cxl/core/memdev.c

@@ -160,6 +160,50 @@ int cxl_trigger_poison_list(struct cxl_memdev *cxlmd)
 }
 EXPORT_SYMBOL_NS_GPL(cxl_trigger_poison_list, CXL);
 
+struct cxl_dpa_to_region_context {
+	struct cxl_region *cxlr;
+	u64 dpa;
+};
+
+static int __cxl_dpa_to_region(struct device *dev, void *arg)
+{
+	struct cxl_dpa_to_region_context *ctx = arg;
+	struct cxl_endpoint_decoder *cxled;
+	u64 dpa = ctx->dpa;
+
+	if (!is_endpoint_decoder(dev))
+		return 0;
+
+	cxled = to_cxl_endpoint_decoder(dev);
+	if (!cxled->dpa_res || !resource_size(cxled->dpa_res))
+		return 0;
+
+	if (dpa > cxled->dpa_res->end || dpa < cxled->dpa_res->start)
+		return 0;
+
+	dev_dbg(dev, "dpa:0x%llx mapped in region:%s\n", dpa,
+		dev_name(&cxled->cxld.region->dev));
+
+	ctx->cxlr = cxled->cxld.region;
+
+	return 1;
+}
+
+static struct cxl_region *cxl_dpa_to_region(struct cxl_memdev *cxlmd, u64 dpa)
+{
+	struct cxl_dpa_to_region_context ctx;
+	struct cxl_port *port;
+
+	ctx = (struct cxl_dpa_to_region_context) {
+		.dpa = dpa,
+	};
+	port = dev_get_drvdata(&cxlmd->dev);
+	if (port && is_cxl_endpoint(port) && port->commit_end != -1)
+		device_for_each_child(&port->dev, &ctx, __cxl_dpa_to_region);
+
+	return ctx.cxlr;
+}
+
 static int cxl_validate_poison_dpa(struct cxl_memdev *cxlmd, u64 dpa)
 {
 	struct cxl_dev_state *cxlds = cxlmd->cxlds;
@@ -189,6 +233,7 @@ int cxl_inject_poison(struct cxl_memdev *cxlmd, u64 dpa)
 	struct cxl_dev_state *cxlds = cxlmd->cxlds;
 	struct cxl_mbox_inject_poison inject;
 	struct cxl_mbox_cmd mbox_cmd;
+	struct cxl_region *cxlr;
 	int rc;
 
 	if (!IS_ENABLED(CONFIG_DEBUG_FS))
@@ -209,6 +254,14 @@ int cxl_inject_poison(struct cxl_memdev *cxlmd, u64 dpa)
 		.payload_in = &inject,
 	};
 	rc = cxl_internal_send_cmd(cxlds, &mbox_cmd);
+	if (rc)
+		goto out;
+
+	cxlr = cxl_dpa_to_region(cxlmd, dpa);
+	if (cxlr)
+		dev_warn_once(cxlds->dev,
+			      "poison inject dpa:%#llx region: %s\n", dpa,
+			      dev_name(&cxlr->dev));
 out:
 	up_read(&cxl_dpa_rwsem);
 
@@ -221,6 +274,7 @@ int cxl_clear_poison(struct cxl_memdev *cxlmd, u64 dpa)
 	struct cxl_dev_state *cxlds = cxlmd->cxlds;
 	struct cxl_mbox_clear_poison clear;
 	struct cxl_mbox_cmd mbox_cmd;
+	struct cxl_region *cxlr;
 	int rc;
 
 	if (!IS_ENABLED(CONFIG_DEBUG_FS))
@@ -252,6 +306,11 @@ int cxl_clear_poison(struct cxl_memdev *cxlmd, u64 dpa)
 	rc = cxl_internal_send_cmd(cxlds, &mbox_cmd);
 	if (rc)
 		goto out;
+
+	cxlr = cxl_dpa_to_region(cxlmd, dpa);
+	if (cxlr)
+		dev_warn_once(cxlds->dev, "poison clear dpa:%#llx region: %s\n",
+			      dpa, dev_name(&cxlr->dev));
 out:
 	up_read(&cxl_dpa_rwsem);