diff --git a/docs/misc/hypfs-paths.pandoc b/docs/misc/hypfs-paths.pandoc
index f134c505d6..9d46e7e44a 100644
--- a/docs/misc/hypfs-paths.pandoc
+++ b/docs/misc/hypfs-paths.pandoc
@@ -152,3 +152,12 @@ The major version of Xen.
 #### /buildinfo/version/minor = INTEGER
 
 The minor version of Xen.
+
+#### /params/
+
+A directory of runtime parameters.
+
+#### /params/*
+
+The individual parameters. The description of the different parameters can be
+found in `docs/misc/xen-command-line.pandoc`.
diff --git a/xen/arch/arm/xen.lds.S b/xen/arch/arm/xen.lds.S
index a497f6a48d..d31bed580d 100644
--- a/xen/arch/arm/xen.lds.S
+++ b/xen/arch/arm/xen.lds.S
@@ -89,6 +89,11 @@ SECTIONS
        __start_schedulers_array = .;
        *(.data.schedulers)
        __end_schedulers_array = .;
+
+       . = ALIGN(4);
+       __paramhypfs_start = .;
+       *(.data.paramhypfs)
+       __paramhypfs_end = .;
        *(.data.rel)
        *(.data.rel.*)
        CONSTRUCTORS
diff --git a/xen/arch/x86/hvm/vmx/vmcs.c b/xen/arch/x86/hvm/vmx/vmcs.c
index 24f2bd6e43..859c753a14 100644
--- a/xen/arch/x86/hvm/vmx/vmcs.c
+++ b/xen/arch/x86/hvm/vmx/vmcs.c
@@ -70,6 +70,30 @@ integer_param("ple_window", ple_window);
 static bool __read_mostly opt_ept_pml = true;
 static s8 __read_mostly opt_ept_ad = -1;
 int8_t __read_mostly opt_ept_exec_sp = -1;
+static char opt_ept_setting[24];
+
+static void update_ept_param_append(const char *str, int val)
+{
+    char *pos = opt_ept_setting + strlen(opt_ept_setting);
+
+    snprintf(pos, sizeof(opt_ept_setting) - (pos - opt_ept_setting),
+             ",%s=%d", str, val);
+}
+
+static void update_ept_param(void)
+{
+    snprintf(opt_ept_setting, sizeof(opt_ept_setting), "pml=%d", opt_ept_pml);
+    if ( opt_ept_ad >= 0 )
+        update_ept_param_append("ad", opt_ept_ad);
+    if ( opt_ept_exec_sp >= 0 )
+        update_ept_param_append("exec-sp", opt_ept_exec_sp);
+}
+
+static void __init init_ept_param(struct param_hypfs *par)
+{
+    update_ept_param();
+    custom_runtime_set_var(par, opt_ept_setting);
+}
 
 static int __init parse_ept_param(const char *s)
 {
@@ -97,6 +121,9 @@ static int __init parse_ept_param(const char *s)
 }
 custom_param("ept", parse_ept_param);
 
+static int parse_ept_param_runtime(const char *s);
+custom_runtime_only_param("ept", parse_ept_param_runtime, init_ept_param);
+
 static int parse_ept_param_runtime(const char *s)
 {
     struct domain *d;
@@ -115,6 +142,10 @@ static int parse_ept_param_runtime(const char *s)
 
     opt_ept_exec_sp = val;
 
+    update_ept_param();
+    custom_runtime_set_var(param_2_parfs(parse_ept_param_runtime),
+                           opt_ept_setting);
+
     rcu_read_lock(&domlist_read_lock);
     for_each_domain ( d )
     {
@@ -144,7 +175,6 @@ static int parse_ept_param_runtime(const char *s)
 
     return 0;
 }
-custom_runtime_only_param("ept", parse_ept_param_runtime);
 
 /* Dynamic (run-time adjusted) execution control flags. */
 u32 vmx_pin_based_exec_control __read_mostly;
diff --git a/xen/arch/x86/pv/domain.c b/xen/arch/x86/pv/domain.c
index 70fae43965..7bec22e810 100644
--- a/xen/arch/x86/pv/domain.c
+++ b/xen/arch/x86/pv/domain.c
@@ -20,8 +20,23 @@ static __read_mostly enum {
     PCID_OFF,
     PCID_ALL,
     PCID_XPTI,
-    PCID_NOXPTI
+    PCID_NOXPTI,
+    PCID_END
 } opt_pcid = PCID_XPTI;
+static const char opt_pcid_2_string[PCID_END][7] = {
+    [PCID_OFF] = "off",
+    [PCID_ALL] = "on",
+    [PCID_XPTI] = "xpti",
+    [PCID_NOXPTI] = "noxpti"
+};
+
+static void __init opt_pcid_init(struct param_hypfs *par)
+{
+    custom_runtime_set_var(par, opt_pcid_2_string[opt_pcid]);
+}
+
+static int parse_pcid(const char *s);
+custom_runtime_param("pcid", parse_pcid, opt_pcid_init);
 
 static int parse_pcid(const char *s)
 {
@@ -55,9 +70,11 @@ static int parse_pcid(const char *s)
         break;
     }
 
+    custom_runtime_set_var(param_2_parfs(parse_pcid),
+                           opt_pcid_2_string[opt_pcid]);
+
     return rc;
 }
-custom_runtime_param("pcid", parse_pcid);
 
 static void noreturn continue_nonidle_domain(struct vcpu *v)
 {
diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
index 7f9459d683..21a37f0f57 100644
--- a/xen/arch/x86/xen.lds.S
+++ b/xen/arch/x86/xen.lds.S
@@ -279,6 +279,11 @@ SECTIONS
        __start_schedulers_array = .;
        *(.data.schedulers)
        __end_schedulers_array = .;
+
+       . = ALIGN(8);
+       __paramhypfs_start = .;
+       *(.data.paramhypfs)
+       __paramhypfs_end = .;
   } :text
 
   DECL_SECTION(.data) {
diff --git a/xen/common/grant_table.c b/xen/common/grant_table.c
index 9fd6e60416..7a63bdd772 100644
--- a/xen/common/grant_table.c
+++ b/xen/common/grant_table.c
@@ -85,8 +85,17 @@ struct grant_table {
     struct grant_table_arch arch;
 };
 
-static int parse_gnttab_limit(const char *param, const char *arg,
-                              unsigned int *valp)
+#define GRANT_CUSTOM_VAL_SZ  12
+
+static void update_gnttab_par(struct param_hypfs *par, unsigned int val,
+                              char *parval)
+{
+    snprintf(parval, GRANT_CUSTOM_VAL_SZ, "%u", val);
+    custom_runtime_set_var(par, parval);
+}
+
+static int parse_gnttab_limit(struct param_hypfs *par, const char *arg,
+                              unsigned int *valp, char *parval)
 {
     const char *e;
     unsigned long val;
@@ -99,28 +108,50 @@ static int parse_gnttab_limit(const char *param, const char *arg,
         return -ERANGE;
 
     *valp = val;
+    update_gnttab_par(par, val, parval);
 
     return 0;
 }
 
 unsigned int __read_mostly opt_max_grant_frames = 64;
+static char __read_mostly opt_max_grant_frames_val[GRANT_CUSTOM_VAL_SZ];
+
+static void __init gnttab_max_frames_init(struct param_hypfs *par)
+{
+    update_gnttab_par(par, opt_max_grant_frames, opt_max_grant_frames_val);
+}
+
+static int parse_gnttab_max_frames(const char *arg);
+custom_runtime_param("gnttab_max_frames", parse_gnttab_max_frames,
+                     gnttab_max_frames_init);
 
 static int parse_gnttab_max_frames(const char *arg)
 {
-    return parse_gnttab_limit("gnttab_max_frames", arg,
-                              &opt_max_grant_frames);
+    return parse_gnttab_limit(param_2_parfs(parse_gnttab_max_frames),
+                              arg, &opt_max_grant_frames,
+                              opt_max_grant_frames_val);
 }
-custom_runtime_param("gnttab_max_frames", parse_gnttab_max_frames);
 
 static unsigned int __read_mostly opt_max_maptrack_frames = 1024;
+static char __read_mostly opt_max_maptrack_frames_val[GRANT_CUSTOM_VAL_SZ];
 
-static int parse_gnttab_max_maptrack_frames(const char *arg)
+static void __init max_maptrack_frames_init(struct param_hypfs *par)
 {
-    return parse_gnttab_limit("gnttab_max_maptrack_frames", arg,
-                              &opt_max_maptrack_frames);
+    update_gnttab_par(par, opt_max_maptrack_frames,
+                      opt_max_maptrack_frames_val);
 }
+
+static int parse_gnttab_max_maptrack_frames(const char *arg);
 custom_runtime_param("gnttab_max_maptrack_frames",
-                     parse_gnttab_max_maptrack_frames);
+                     parse_gnttab_max_maptrack_frames,
+                     max_maptrack_frames_init);
+
+static int parse_gnttab_max_maptrack_frames(const char *arg)
+{
+    return parse_gnttab_limit(param_2_parfs(parse_gnttab_max_maptrack_frames),
+                              arg, &opt_max_maptrack_frames,
+                              opt_max_maptrack_frames_val);
+}
 
 #ifndef GNTTAB_MAX_VERSION
 #define GNTTAB_MAX_VERSION 2
diff --git a/xen/common/hypfs.c b/xen/common/hypfs.c
index 986b829934..df951526db 100644
--- a/xen/common/hypfs.c
+++ b/xen/common/hypfs.c
@@ -10,6 +10,7 @@
 #include <xen/hypercall.h>
 #include <xen/hypfs.h>
 #include <xen/lib.h>
+#include <xen/param.h>
 #include <xen/rwlock.h>
 #include <public/hypfs.h>
 
@@ -279,6 +280,36 @@ int hypfs_write_bool(struct hypfs_entry_leaf *leaf,
     return 0;
 }
 
+int hypfs_write_custom(struct hypfs_entry_leaf *leaf,
+                       XEN_GUEST_HANDLE_PARAM(void) uaddr, unsigned long ulen)
+{
+    struct param_hypfs *p;
+    char *buf;
+    int ret;
+
+    buf = xzalloc_array(char, ulen);
+    if ( !buf )
+        return -ENOMEM;
+
+    ret = -EFAULT;
+    if ( copy_from_guest(buf, uaddr, ulen) )
+        goto out;
+
+    ret = -EDOM;
+    if ( memchr(buf, 0, ulen) != (buf + ulen - 1) )
+        goto out;
+
+    p = container_of(leaf, struct param_hypfs, hypfs);
+    ret = p->param->par.func(buf);
+
+    if ( !ret )
+        leaf->e.size = ulen;
+
+ out:
+    xfree(buf);
+    return ret;
+}
+
 static int hypfs_write(struct hypfs_entry *entry,
                        XEN_GUEST_HANDLE_PARAM(void) uaddr, unsigned long ulen)
 {
@@ -348,3 +379,13 @@ long do_hypfs_op(unsigned int cmd,
 
     return ret;
 }
+
+void hypfs_write_lock(void)
+{
+    write_lock(&hypfs_lock);
+}
+
+void hypfs_write_unlock(void)
+{
+    write_unlock(&hypfs_lock);
+}
diff --git a/xen/common/kernel.c b/xen/common/kernel.c
index 4b7bc28afb..7516242337 100644
--- a/xen/common/kernel.c
+++ b/xen/common/kernel.c
@@ -198,7 +198,13 @@ static void __init _cmdline_parse(const char *cmdline)
 
 int runtime_parse(const char *line)
 {
-    return parse_params(line, __param_start, __param_end);
+    int ret;
+
+    hypfs_write_lock();
+    ret = parse_params(line, __param_start, __param_end);
+    hypfs_write_unlock();
+
+    return ret;
 }
 
 /**
@@ -433,6 +439,25 @@ static int __init buildinfo_init(void)
 }
 __initcall(buildinfo_init);
 
+static HYPFS_DIR_INIT(params, "params");
+
+static int __init param_init(void)
+{
+    struct param_hypfs *param;
+
+    hypfs_add_dir(&hypfs_root, &params, true);
+
+    for ( param = __paramhypfs_start; param < __paramhypfs_end; param++ )
+    {
+        if ( param->init_leaf )
+            param->init_leaf(param);
+        hypfs_add_leaf(&params, &param->hypfs, true);
+    }
+
+    return 0;
+}
+__initcall(param_init);
+
 # define DO(fn) long do_##fn
 
 #endif
diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c
index 913ae1b66a..b18b431fa8 100644
--- a/xen/drivers/char/console.c
+++ b/xen/drivers/char/console.c
@@ -75,12 +75,29 @@ enum con_timestamp_mode
     TSM_DATE_MS,       /* [YYYY-MM-DD HH:MM:SS.mmm] */
     TSM_BOOT,          /* [SSSSSS.uuuuuu] */
     TSM_RAW,           /* [XXXXXXXXXXXXXXXX] */
+    TSM_END
+};
+
+static const char con_timestamp_mode_2_string[TSM_END][7] = {
+    [TSM_NONE] = "none",
+    [TSM_DATE] = "date",
+    [TSM_DATE_MS] = "datems",
+    [TSM_BOOT] = "boot",
+    [TSM_RAW] = "raw"
 };
 
 static enum con_timestamp_mode __read_mostly opt_con_timestamp_mode = TSM_NONE;
 
+static void con_timestamp_mode_upd(struct param_hypfs *par)
+{
+    const char *val = con_timestamp_mode_2_string[opt_con_timestamp_mode];
+
+    custom_runtime_set_var_sz(par, val, 7);
+}
+
 static int parse_console_timestamps(const char *s);
-custom_runtime_param("console_timestamps", parse_console_timestamps);
+custom_runtime_param("console_timestamps", parse_console_timestamps,
+                     con_timestamp_mode_upd);
 
 /* conring_size: allows a large console ring than default (16kB). */
 static uint32_t __initdata opt_conring_size;
@@ -133,16 +150,39 @@ static DEFINE_SPINLOCK(console_lock);
 #define XENLOG_DEFAULT       1 /* XENLOG_WARNING */
 #define XENLOG_GUEST_DEFAULT 1 /* XENLOG_WARNING */
 
+#define LOGLVL_VAL_SZ 16
 static int __read_mostly xenlog_upper_thresh = XENLOG_UPPER_THRESHOLD;
 static int __read_mostly xenlog_lower_thresh = XENLOG_LOWER_THRESHOLD;
+static char xenlog_val[LOGLVL_VAL_SZ];
 static int __read_mostly xenlog_guest_upper_thresh =
     XENLOG_GUEST_UPPER_THRESHOLD;
 static int __read_mostly xenlog_guest_lower_thresh =
     XENLOG_GUEST_LOWER_THRESHOLD;
+static char xenlog_guest_val[LOGLVL_VAL_SZ];
 
 static int parse_loglvl(const char *s);
 static int parse_guest_loglvl(const char *s);
 
+static char *lvl2opt[] = { "none", "error", "warning", "info", "all" };
+
+static void xenlog_update_val(int lower, int upper, char *val)
+{
+    snprintf(val, LOGLVL_VAL_SZ, "%s/%s", lvl2opt[lower], lvl2opt[upper]);
+}
+
+static void __init xenlog_init(struct param_hypfs *par)
+{
+    xenlog_update_val(xenlog_lower_thresh, xenlog_upper_thresh, xenlog_val);
+    custom_runtime_set_var(par, xenlog_val);
+}
+
+static void __init xenlog_guest_init(struct param_hypfs *par)
+{
+    xenlog_update_val(xenlog_guest_lower_thresh, xenlog_guest_upper_thresh,
+                      xenlog_guest_val);
+    custom_runtime_set_var(par, xenlog_guest_val);
+}
+
 /*
  * <lvl> := none|error|warning|info|debug|all
  * loglvl=<lvl_print_always>[/<lvl_print_ratelimit>]
@@ -151,8 +191,8 @@ static int parse_guest_loglvl(const char *s);
  * Similar definitions for guest_loglvl, but applies to guest tracing.
  * Defaults: loglvl=warning ; guest_loglvl=none/warning
  */
-custom_runtime_param("loglvl", parse_loglvl);
-custom_runtime_param("guest_loglvl", parse_guest_loglvl);
+custom_runtime_param("loglvl", parse_loglvl, xenlog_init);
+custom_runtime_param("guest_loglvl", parse_guest_loglvl, xenlog_guest_init);
 
 static atomic_t print_everything = ATOMIC_INIT(0);
 
@@ -173,7 +213,7 @@ static int __parse_loglvl(const char *s, const char **ps)
     return 2; /* sane fallback */
 }
 
-static int _parse_loglvl(const char *s, int *lower, int *upper)
+static int _parse_loglvl(const char *s, int *lower, int *upper, char *val)
 {
     *lower = *upper = __parse_loglvl(s, &s);
     if ( *s == '/' )
@@ -181,18 +221,21 @@ static int _parse_loglvl(const char *s, int *lower, int *upper)
     if ( *upper < *lower )
         *upper = *lower;
 
+    xenlog_update_val(*lower, *upper, val);
+
     return *s ? -EINVAL : 0;
 }
 
 static int parse_loglvl(const char *s)
 {
-    return _parse_loglvl(s, &xenlog_lower_thresh, &xenlog_upper_thresh);
+    return _parse_loglvl(s, &xenlog_lower_thresh, &xenlog_upper_thresh,
+                         xenlog_val);
 }
 
 static int parse_guest_loglvl(const char *s)
 {
     return _parse_loglvl(s, &xenlog_guest_lower_thresh,
-                         &xenlog_guest_upper_thresh);
+                         &xenlog_guest_upper_thresh, xenlog_guest_val);
 }
 
 static char *loglvl_str(int lvl)
@@ -727,13 +770,17 @@ static int printk_prefix_check(char *p, char **pp)
 
 static int parse_console_timestamps(const char *s)
 {
+    struct param_hypfs *par = param_2_parfs(parse_console_timestamps);
+
     switch ( parse_bool(s, NULL) )
     {
     case 0:
         opt_con_timestamp_mode = TSM_NONE;
+        con_timestamp_mode_upd(par);
         return 0;
     case 1:
         opt_con_timestamp_mode = TSM_DATE;
+        con_timestamp_mode_upd(par);
         return 0;
     }
     if ( *s == '\0' || /* Compat for old booleanparam() */
@@ -750,6 +797,8 @@ static int parse_console_timestamps(const char *s)
     else
         return -EINVAL;
 
+    con_timestamp_mode_upd(par);
+
     return 0;
 }
 
diff --git a/xen/include/xen/hypfs.h b/xen/include/xen/hypfs.h
index 85588e2a59..3c3b1b056d 100644
--- a/xen/include/xen/hypfs.h
+++ b/xen/include/xen/hypfs.h
@@ -112,5 +112,9 @@ int hypfs_write_leaf(struct hypfs_entry_leaf *leaf,
                      XEN_GUEST_HANDLE_PARAM(void) uaddr, unsigned long ulen);
 int hypfs_write_bool(struct hypfs_entry_leaf *leaf,
                      XEN_GUEST_HANDLE_PARAM(void) uaddr, unsigned long ulen);
+int hypfs_write_custom(struct hypfs_entry_leaf *leaf,
+                       XEN_GUEST_HANDLE_PARAM(void) uaddr, unsigned long ulen);
+void hypfs_write_lock(void);
+void hypfs_write_unlock(void);
 
 #endif /* __XEN_HYPFS_H__ */
diff --git a/xen/include/xen/param.h b/xen/include/xen/param.h
index d4578cd27f..5cf2149279 100644
--- a/xen/include/xen/param.h
+++ b/xen/include/xen/param.h
@@ -1,6 +1,7 @@
 #ifndef _XEN_PARAM_H
 #define _XEN_PARAM_H
 
+#include <xen/hypfs.h>
 #include <xen/init.h>
 #include <xen/lib.h>
 #include <xen/stdbool.h>
@@ -25,10 +26,18 @@ struct kernel_param {
     } par;
 };
 
+struct param_hypfs {
+    const struct kernel_param *param;
+    struct hypfs_entry_leaf hypfs;
+    void (*init_leaf)(struct param_hypfs *par);
+};
+
 extern const struct kernel_param __setup_start[], __setup_end[];
 extern const struct kernel_param __param_start[], __param_end[];
+extern struct param_hypfs __paramhypfs_start[], __paramhypfs_end[];
 
 #define __dataparam       __used_section(".data.param")
+#define __paramhypfs      __used_section(".data.paramhypfs")
 
 #define __param(att)      static const att \
     __attribute__((__aligned__(sizeof(void *)))) struct kernel_param
@@ -79,41 +88,103 @@ extern const struct kernel_param __param_start[], __param_end[];
           .type = OPT_IGNORE }
 
 #define __rtparam         __param(__dataparam)
+#define __paramfs         static __paramhypfs \
+    __attribute__((__aligned__(sizeof(void *)))) struct param_hypfs
+
+#define custom_runtime_set_var_sz(parfs, var, sz) \
+    { \
+        (parfs)->hypfs.content = &(var); \
+        (parfs)->hypfs.e.max_size = sz; \
+        (parfs)->hypfs.e.size = strlen(var) + 1; \
+    }
+#define custom_runtime_set_var(parfs, var) \
+    custom_runtime_set_var_sz(parfs, var, sizeof(var))
 
-#define custom_runtime_only_param(_name, _var) \
+#define param_2_parfs(par) &__parfs_##par
+
+/* initfunc needs to set size and content, e.g. via custom_runtime_set_var(). */
+#define custom_runtime_only_param(_name, _var, initfunc) \
     __rtparam __rtpar_##_var = \
       { .name = _name, \
           .type = OPT_CUSTOM, \
-          .par.func = _var }
+          .par.func = _var }; \
+    __paramfs __parfs_##_var = \
+        { .param = &__rtpar_##_var, \
+          .init_leaf = initfunc, \
+          .hypfs.e.type = XEN_HYPFS_TYPE_STRING, \
+          .hypfs.e.encoding = XEN_HYPFS_ENC_PLAIN, \
+          .hypfs.e.name = _name, \
+          .hypfs.e.read = hypfs_read_leaf, \
+          .hypfs.e.write = hypfs_write_custom }
 #define boolean_runtime_only_param(_name, _var) \
     __rtparam __rtpar_##_var = \
         { .name = _name, \
           .type = OPT_BOOL, \
           .len = sizeof(_var) + \
                  BUILD_BUG_ON_ZERO(sizeof(_var) != sizeof(bool)), \
-          .par.var = &_var }
+          .par.var = &_var }; \
+    __paramfs __parfs_##_var = \
+        { .param = &__rtpar_##_var, \
+          .hypfs.e.type = XEN_HYPFS_TYPE_BOOL, \
+          .hypfs.e.encoding = XEN_HYPFS_ENC_PLAIN, \
+          .hypfs.e.name = _name, \
+          .hypfs.e.size = sizeof(_var), \
+          .hypfs.e.max_size = sizeof(_var), \
+          .hypfs.e.read = hypfs_read_leaf, \
+          .hypfs.e.write = hypfs_write_bool, \
+          .hypfs.content = &_var }
 #define integer_runtime_only_param(_name, _var) \
     __rtparam __rtpar_##_var = \
         { .name = _name, \
           .type = OPT_UINT, \
           .len = sizeof(_var), \
-          .par.var = &_var }
+          .par.var = &_var }; \
+    __paramfs __parfs_##_var = \
+        { .param = &__rtpar_##_var, \
+          .hypfs.e.type = XEN_HYPFS_TYPE_UINT, \
+          .hypfs.e.encoding = XEN_HYPFS_ENC_PLAIN, \
+          .hypfs.e.name = _name, \
+          .hypfs.e.size = sizeof(_var), \
+          .hypfs.e.max_size = sizeof(_var), \
+          .hypfs.e.read = hypfs_read_leaf, \
+          .hypfs.e.write = hypfs_write_leaf, \
+          .hypfs.content = &_var }
 #define size_runtime_only_param(_name, _var) \
     __rtparam __rtpar_##_var = \
         { .name = _name, \
           .type = OPT_SIZE, \
           .len = sizeof(_var), \
-          .par.var = &_var }
+          .par.var = &_var }; \
+    __paramfs __parfs_##_var = \
+        { .param = &__rtpar_##_var, \
+          .hypfs.e.type = XEN_HYPFS_TYPE_UINT, \
+          .hypfs.e.encoding = XEN_HYPFS_ENC_PLAIN, \
+          .hypfs.e.name = _name, \
+          .hypfs.e.size = sizeof(_var), \
+          .hypfs.e.max_size = sizeof(_var), \
+          .hypfs.e.read = hypfs_read_leaf, \
+          .hypfs.e.write = hypfs_write_leaf, \
+          .hypfs.content = &_var }
 #define string_runtime_only_param(_name, _var) \
     __rtparam __rtpar_##_var = \
         { .name = _name, \
           .type = OPT_STR, \
           .len = sizeof(_var), \
-          .par.var = &_var }
+          .par.var = &_var }; \
+    __paramfs __parfs_##_var = \
+        { .param = &__rtpar_##_var, \
+          .hypfs.e.type = XEN_HYPFS_TYPE_STRING, \
+          .hypfs.e.encoding = XEN_HYPFS_ENC_PLAIN, \
+          .hypfs.e.name = _name, \
+          .hypfs.e.size = sizeof(_var), \
+          .hypfs.e.max_size = sizeof(_var), \
+          .hypfs.e.read = hypfs_read_leaf, \
+          .hypfs.e.write = hypfs_write_leaf, \
+          .hypfs.content = &_var }
 
-#define custom_runtime_param(_name, _var) \
+#define custom_runtime_param(_name, _var, initfunc) \
     custom_param(_name, _var); \
-    custom_runtime_only_param(_name, _var)
+    custom_runtime_only_param(_name, _var, initfunc)
 #define boolean_runtime_param(_name, _var) \
     boolean_param(_name, _var); \
     boolean_runtime_only_param(_name, _var)
