cxl/mem: Introduce security state sysfs file

Add a read-only sysfs file to display the security state
of a device (currently only pmem):

    /sys/bus/cxl/devices/memX/security/state

This introduces a cxl_security_state structure that is
to be the placeholder for common CXL security features.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Fan Ni <fan.ni@samsung.com>
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/20230612181038.14421-3-dave@stgolabs.net
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/Documentation/ABI/testing/sysfs-bus-cxl b/Documentation/ABI/testing/sysfs-bus-cxl
index 48ac0d911801ade392f89e76daea4d77be6fdebb..721a44d8a482a7dc5899b1702355f45ee1e598cb 100644 (file)
--- a/Documentation/ABI/testing/sysfs-bus-cxl
+++ b/Documentation/ABI/testing/sysfs-bus-cxl
@@ -58,6 +58,16 @@ Description:
                affinity for this device.
 
 
+What:          /sys/bus/cxl/devices/memX/security/state
+Date:          June, 2023
+KernelVersion: v6.5
+Contact:       linux-cxl@vger.kernel.org
+Description:
+               (RO) Reading this file will display the CXL security state for
+               that device. Such states can be: 'disabled', or those available
+               only for persistent memory: 'locked', 'unlocked' or 'frozen'.
+
+
 What:          /sys/bus/cxl/devices/*/devtype
 Date:          June, 2021
 KernelVersion: v5.14

diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
index 057a432672900d913743aa6842c96b508d34683a..1bbb7e39fc93ed2c5306b706ab35e207c4787c41 100644 (file)
--- a/drivers/cxl/core/memdev.c
+++ b/drivers/cxl/core/memdev.c
@@ -107,6 +107,28 @@ static ssize_t numa_node_show(struct device *dev, struct device_attribute *attr,
 }
 static DEVICE_ATTR_RO(numa_node);
 
+static ssize_t security_state_show(struct device *dev,
+                                  struct device_attribute *attr,
+                                  char *buf)
+{
+       struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
+       struct cxl_dev_state *cxlds = cxlmd->cxlds;
+       unsigned long state = cxlds->security.state;
+
+       if (!(state & CXL_PMEM_SEC_STATE_USER_PASS_SET))
+               return sysfs_emit(buf, "disabled\n");
+       if (state & CXL_PMEM_SEC_STATE_FROZEN ||
+           state & CXL_PMEM_SEC_STATE_MASTER_PLIMIT ||
+           state & CXL_PMEM_SEC_STATE_USER_PLIMIT)
+               return sysfs_emit(buf, "frozen\n");
+       if (state & CXL_PMEM_SEC_STATE_LOCKED)
+               return sysfs_emit(buf, "locked\n");
+       else
+               return sysfs_emit(buf, "unlocked\n");
+}
+static struct device_attribute dev_attr_security_state =
+       __ATTR(state, 0444, security_state_show, NULL);
+
 static int cxl_get_poison_by_memdev(struct cxl_memdev *cxlmd)
 {
        struct cxl_dev_state *cxlds = cxlmd->cxlds;
@@ -352,6 +374,11 @@ static struct attribute *cxl_memdev_ram_attributes[] = {
        NULL,
 };
 
+static struct attribute *cxl_memdev_security_attributes[] = {
+       &dev_attr_security_state.attr,
+       NULL,
+};
+
 static umode_t cxl_memdev_visible(struct kobject *kobj, struct attribute *a,
                                  int n)
 {
@@ -375,10 +402,16 @@ static struct attribute_group cxl_memdev_pmem_attribute_group = {
        .attrs = cxl_memdev_pmem_attributes,
 };
 
+static struct attribute_group cxl_memdev_security_attribute_group = {
+       .name = "security",
+       .attrs = cxl_memdev_security_attributes,
+};
+
 static const struct attribute_group *cxl_memdev_attribute_groups[] = {
        &cxl_memdev_attribute_group,
        &cxl_memdev_ram_attribute_group,
        &cxl_memdev_pmem_attribute_group,
+       &cxl_memdev_security_attribute_group,
        NULL,
 };
 

diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index 1d8e81c87c6a87aa5557b4373fc2fcf2d6d63bea..091f1200736b2a2e72b28b3b69f7c0e7c9bc43df 100644 (file)
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -260,6 +260,15 @@ struct cxl_poison_state {
        struct mutex lock;  /* Protect reads of poison list */
 };
 
+/**
+ * struct cxl_security_state - Device security state
+ *
+ * @state: state of last security operation
+ */
+struct cxl_security_state {
+       unsigned long state;
+};
+
 /**
  * struct cxl_dev_state - The driver device state
  *
@@ -336,6 +345,7 @@ struct cxl_dev_state {
 
        struct cxl_event_state event;
        struct cxl_poison_state poison;
+       struct cxl_security_state security;
 
        struct rcuwait mbox_wait;
        int (*mbox_send)(struct cxl_dev_state *cxlds, struct cxl_mbox_cmd *cmd);

diff --git a/drivers/cxl/security.c b/drivers/cxl/security.c
index 4ad4bda2d18e0f5df98dd32626a1f33c20d13012..9da6785dfd315e5fcf16e66ce08ad08ec78eb714 100644 (file)
--- a/drivers/cxl/security.c
+++ b/drivers/cxl/security.c
@@ -34,6 +34,9 @@ static unsigned long cxl_pmem_get_security_flags(struct nvdimm *nvdimm,
                return 0;
 
        sec_out = le32_to_cpu(out.flags);
+       /* cache security state */
+       cxlds->security.state = sec_out;
+
        if (ptype == NVDIMM_MASTER) {
                if (sec_out & CXL_PMEM_SEC_STATE_MASTER_PASS_SET)
                        set_bit(NVDIMM_SECURITY_UNLOCKED, &security_flags);