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[96.255.20.138]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-4eda57ad8e6sm3293421cf.27.2025.11.07.14.50.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 07 Nov 2025 14:50:27 -0800 (PST) From: Gregory Price To: linux-mm@kvack.org Cc: linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org, nvdimm@lists.linux.dev, linux-fsdevel@vger.kernel.org, cgroups@vger.kernel.org, dave@stgolabs.net, jonathan.cameron@huawei.com, dave.jiang@intel.com, alison.schofield@intel.com, vishal.l.verma@intel.com, ira.weiny@intel.com, dan.j.williams@intel.com, longman@redhat.com, akpm@linux-foundation.org, david@redhat.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, osalvador@suse.de, ziy@nvidia.com, matthew.brost@intel.com, joshua.hahnjy@gmail.com, rakie.kim@sk.com, byungchul@sk.com, gourry@gourry.net, ying.huang@linux.alibaba.com, apopple@nvidia.com, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, tj@kernel.org, hannes@cmpxchg.org, mkoutny@suse.com, kees@kernel.org, muchun.song@linux.dev, roman.gushchin@linux.dev, shakeel.butt@linux.dev, rientjes@google.com, jackmanb@google.com, cl@gentwo.org, harry.yoo@oracle.com, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, zhengqi.arch@bytedance.com, yosry.ahmed@linux.dev, nphamcs@gmail.com, chengming.zhou@linux.dev, fabio.m.de.francesco@linux.intel.com, rrichter@amd.com, ming.li@zohomail.com, usamaarif642@gmail.com, brauner@kernel.org, oleg@redhat.com, namcao@linutronix.de, escape@linux.alibaba.com, dongjoo.seo1@samsung.com Subject: [RFC PATCH 8/9] drivers/cxl: add protected_memory bit to cxl region Date: Fri, 7 Nov 2025 17:49:53 -0500 Message-ID: <20251107224956.477056-9-gourry@gourry.net> X-Mailer: git-send-email 2.51.1 In-Reply-To: <20251107224956.477056-1-gourry@gourry.net> References: <20251107224956.477056-1-gourry@gourry.net> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add protected_memory bit to cxl region. The setting is subsequently forwarded to the dax device it creates. This allows the auto-hotplug process to occur without an intermediate step requiring udev to poke the DAX device protected memory bit explicitly before onlining. Signed-off-by: Gregory Price --- drivers/cxl/core/region.c | 30 ++++++++++++++++++++++++++++++ drivers/cxl/cxl.h | 2 ++ drivers/dax/cxl.c | 1 + 3 files changed, 33 insertions(+) diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c index b06fee1978ba..a0e28821961c 100644 --- a/drivers/cxl/core/region.c +++ b/drivers/cxl/core/region.c @@ -754,6 +754,35 @@ static ssize_t size_show(struct device *dev, struct de= vice_attribute *attr, } static DEVICE_ATTR_RW(size); =20 +static ssize_t protected_memory_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct cxl_region *cxlr =3D to_cxl_region(dev); + + return sysfs_emit(buf, "%d\n", cxlr->protected_memory); +} + +static ssize_t protected_memory_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t len) +{ + struct cxl_region *cxlr =3D to_cxl_region(dev); + bool val; + int rc; + + rc =3D kstrtobool(buf, &val); + if (rc) + return rc; + + ACQUIRE(rwsem_write_kill, rwsem)(&cxl_rwsem.region); + if ((rc =3D ACQUIRE_ERR(rwsem_read_intr, &rwsem))) + return rc; + + cxlr->protected_memory =3D val; + return len; +} +static DEVICE_ATTR_RW(protected_memory); + static struct attribute *cxl_region_attrs[] =3D { &dev_attr_uuid.attr, &dev_attr_commit.attr, @@ -762,6 +791,7 @@ static struct attribute *cxl_region_attrs[] =3D { &dev_attr_resource.attr, &dev_attr_size.attr, &dev_attr_mode.attr, + &dev_attr_protected_memory.attr, NULL, }; =20 diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h index 231ddccf8977..0ff4898224ba 100644 --- a/drivers/cxl/cxl.h +++ b/drivers/cxl/cxl.h @@ -530,6 +530,7 @@ enum cxl_partition_mode { * @coord: QoS access coordinates for the region * @node_notifier: notifier for setting the access coordinates to node * @adist_notifier: notifier for calculating the abstract distance of node + * @protected_memory: mark region memory as protected from kernel allocati= on */ struct cxl_region { struct device dev; @@ -543,6 +544,7 @@ struct cxl_region { struct access_coordinate coord[ACCESS_COORDINATE_MAX]; struct notifier_block node_notifier; struct notifier_block adist_notifier; + bool protected_memory; }; =20 struct cxl_nvdimm_bridge { diff --git a/drivers/dax/cxl.c b/drivers/dax/cxl.c index 13cd94d32ff7..a4232a5507b5 100644 --- a/drivers/dax/cxl.c +++ b/drivers/dax/cxl.c @@ -27,6 +27,7 @@ static int cxl_dax_region_probe(struct device *dev) .id =3D -1, .size =3D range_len(&cxlr_dax->hpa_range), .memmap_on_memory =3D true, + .protected_memory =3D cxlr->protected_memory, }; =20 return PTR_ERR_OR_ZERO(devm_create_dev_dax(&data)); --=20 2.51.1