s390/cio: Externalize full CMG characteristics

JIRA: https://issues.redhat.com/browse/RHEL-50790

commit 2f4b3b8
Author: Peter Oberparleiter <oberpar@linux.ibm.com>
Date:   Thu Nov 7 15:50:36 2024 +0100

    s390/cio: Externalize full CMG characteristics

    The current "measurement_chars" CHPID sysfs attribute exposes only a
    limited, validity-filtered portion of data from the associated Channel-
    Measurements Characteristics Block (CMCB). New machine models add data
    that is relevant for userspace tooling to the "header"-portion of the
    CMCB. This data that is not currently accessible to userspace.

    To prevent having to add new sysfs attributes whenever a new bit of data
    is added to the CMCB "header", add a new sysfs attribute named
    "measurement_chars_full" that exposes the full, unfiltered CMCB.

    Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
    Reviewed-by: Vineeth Vijayan <vneethv@linux.ibm.com>
    Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

Signed-off-by: Mete Durlu <mdurlu@redhat.com>

Author: Mete Durlu

drivers/s390/cio/chp.c

@@ -144,6 +144,18 @@ static ssize_t measurement_chars_read(struct file *filp, struct kobject *kobj,
 }
 static BIN_ATTR_ADMIN_RO(measurement_chars, sizeof(struct cmg_chars));
 
+static ssize_t measurement_chars_full_read(struct file *filp,
+					   struct kobject *kobj,
+					   struct bin_attribute *bin_attr,
+					   char *buf, loff_t off, size_t count)
+{
+	struct channel_path *chp = to_channelpath(kobj_to_dev(kobj));
+
+	return memory_read_from_buffer(buf, count, &off, &chp->cmcb,
+				       sizeof(chp->cmcb));
+}
+static BIN_ATTR_ADMIN_RO(measurement_chars_full, sizeof(struct cmg_cmcb));
+
 static ssize_t chp_measurement_copy_block(void *buf, loff_t off, size_t count,
 					  struct kobject *kobj, bool extended)
 {
@@ -201,6 +213,7 @@ static BIN_ATTR_ADMIN_RO(ext_measurement, sizeof(struct cmg_ext_entry));
 
 static struct bin_attribute *measurement_attrs[] = {
 	&bin_attr_measurement_chars,
+	&bin_attr_measurement_chars_full,
 	&bin_attr_measurement,
 	&bin_attr_ext_measurement,
 	NULL,

drivers/s390/cio/chp.h

@@ -54,6 +54,7 @@ struct channel_path {
 	int extended;
 	unsigned long speed;
 	struct cmg_chars cmg_chars;
+	struct cmg_cmcb cmcb;
 };
 
 /* Return channel_path struct for given chpid. */

drivers/s390/cio/chsc.c

@@ -1078,19 +1078,7 @@ int chsc_get_channel_measurement_chars(struct channel_path *chp)
 		u32 zeroes1;
 		struct chsc_header response;
 		u32 zeroes2;
-		u32 not_valid : 1;
-		u32 shared : 1;
-		u32 extended : 1;
-		u32 : 21;
-		u32 chpid : 8;
-		u32 cmcv : 5;
-		u32 : 7;
-		u32 cmgp : 4;
-		u32 cmgq : 8;
-		u32 cmg : 8;
-		u32 : 16;
-		u32 cmgs : 16;
-		u32 data[NR_MEASUREMENT_CHARS];
+		struct cmg_cmcb cmcb;
 	} *scmc_area;
 
 	chp->shared = -1;
@@ -1121,15 +1109,16 @@ int chsc_get_channel_measurement_chars(struct channel_path *chp)
 			      scmc_area->response.code);
 		goto out;
 	}
-	if (scmc_area->not_valid)
+	chp->cmcb = scmc_area->cmcb;
+	if (scmc_area->cmcb.not_valid)
 		goto out;
 
-	chp->cmg = scmc_area->cmg;
-	chp->shared = scmc_area->shared;
-	chp->extended = scmc_area->extended;
-	chp->speed = scmc_get_speed(scmc_area->cmgs, scmc_area->cmgp);
-	chsc_initialize_cmg_chars(chp, scmc_area->cmcv,
-				  (struct cmg_chars *) &scmc_area->data);
+	chp->cmg = scmc_area->cmcb.cmg;
+	chp->shared = scmc_area->cmcb.shared;
+	chp->extended = scmc_area->cmcb.extended;
+	chp->speed = scmc_get_speed(scmc_area->cmcb.cmgs, scmc_area->cmcb.cmgp);
+	chsc_initialize_cmg_chars(chp, scmc_area->cmcb.cmcv,
+				  (struct cmg_chars *)&scmc_area->cmcb.data);
 out:
 	spin_unlock_irqrestore(&chsc_page_lock, flags);
 	return ret;

drivers/s390/cio/chsc.h

@@ -17,6 +17,22 @@ struct cmg_chars {
 	u32 values[NR_MEASUREMENT_CHARS];
 };
 
+struct cmg_cmcb {
+	u32 not_valid : 1;
+	u32 shared    : 1;
+	u32 extended  : 1;
+	u32	      : 21;
+	u32 chpid     : 8;
+	u32 cmcv      : 5;
+	u32	      : 7;
+	u32 cmgp      : 4;
+	u32 cmgq      : 8;
+	u32 cmg       : 8;
+	u32	      : 16;
+	u32 cmgs      : 16;
+	u32 data[NR_MEASUREMENT_CHARS];
+};
+
 #define NR_MEASUREMENT_ENTRIES 8
 struct cmg_entry {
 	u32 values[NR_MEASUREMENT_ENTRIES];