s390/ipl: add support to control memory clearing for nvme re-IPL

Re-IPL for nvme is currently done by using diag 308 with the "Load Clear"
subcode, which means that all memory will be cleared.
This can increase re-IPL duration considerably on very large machines.

For list-directed IPL like nvme or fcp IPL, a "Load Normal" subcode was
introduced with z14. The "Load Normal" diag 308 subcode allows to re-IPL
without clearing memory.

This patch adds a new "clear" sysfs attribute to /sys/firmware/reipl/nvme,
which can be set to either "0" or "1" to disable or enable re-IPL with
memory clearing. The default value is "0", which disables memory clearing.

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Tested-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index c5f9d6f88d27596f5a00a533c0d55b4028ad17b1..98b3aca1de8e1daaef0aa5a99a2f35c5e3cd822d 100644 (file)
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -156,6 +156,7 @@ static struct ipl_parameter_block *dump_block_ccw;
 
 static struct sclp_ipl_info sclp_ipl_info;
 
+static bool reipl_nvme_clear;
 static bool reipl_fcp_clear;
 static bool reipl_ccw_clear;
 
@@ -886,6 +887,24 @@ static struct attribute_group reipl_nvme_attr_group = {
        .bin_attrs = reipl_nvme_bin_attrs
 };
 
+static ssize_t reipl_nvme_clear_show(struct kobject *kobj,
+                                    struct kobj_attribute *attr, char *page)
+{
+       return sprintf(page, "%u\n", reipl_nvme_clear);
+}
+
+static ssize_t reipl_nvme_clear_store(struct kobject *kobj,
+                                     struct kobj_attribute *attr,
+                                     const char *buf, size_t len)
+{
+       if (strtobool(buf, &reipl_nvme_clear) < 0)
+               return -EINVAL;
+       return len;
+}
+
+static struct kobj_attribute sys_reipl_nvme_clear_attr =
+       __ATTR(clear, 0644, reipl_nvme_clear_show, reipl_nvme_clear_store);
+
 /* CCW reipl device attributes */
 DEFINE_IPL_CCW_ATTR_RW(reipl_ccw, device, reipl_block_ccw->ccw);
 
@@ -1112,7 +1131,10 @@ static void __reipl_run(void *unused)
                break;
        case IPL_TYPE_NVME:
                diag308(DIAG308_SET, reipl_block_nvme);
-               diag308(DIAG308_LOAD_CLEAR, NULL);
+               if (reipl_nvme_clear)
+                       diag308(DIAG308_LOAD_CLEAR, NULL);
+               else
+                       diag308(DIAG308_LOAD_NORMAL, NULL);
                break;
        case IPL_TYPE_NSS:
                diag308(DIAG308_SET, reipl_block_nss);
@@ -1233,8 +1255,9 @@ static int __init reipl_fcp_init(void)
                                       &sys_reipl_fcp_clear_attr.attr);
                if (rc)
                        goto out2;
-       } else
+       } else {
                reipl_fcp_clear = true;
+       }
 
        if (ipl_info.type == IPL_TYPE_FCP) {
                memcpy(reipl_block_fcp, &ipl_block, sizeof(ipl_block));
@@ -1280,10 +1303,16 @@ static int __init reipl_nvme_init(void)
        }
 
        rc = sysfs_create_group(&reipl_nvme_kset->kobj, &reipl_nvme_attr_group);
-       if (rc) {
-               kset_unregister(reipl_nvme_kset);
-               free_page((unsigned long) reipl_block_nvme);
-               return rc;
+       if (rc)
+               goto out1;
+
+       if (test_facility(141)) {
+               rc = sysfs_create_file(&reipl_nvme_kset->kobj,
+                                      &sys_reipl_nvme_clear_attr.attr);
+               if (rc)
+                       goto out2;
+       } else {
+               reipl_nvme_clear = true;
        }
 
        if (ipl_info.type == IPL_TYPE_NVME) {
@@ -1304,6 +1333,13 @@ static int __init reipl_nvme_init(void)
        }
        reipl_capabilities |= IPL_TYPE_NVME;
        return 0;
+
+out2:
+       sysfs_remove_group(&reipl_nvme_kset->kobj, &reipl_nvme_attr_group);
+out1:
+       kset_unregister(reipl_nvme_kset);
+       free_page((unsigned long) reipl_block_nvme);
+       return rc;
 }
 
 static int __init reipl_type_init(void)