From: Harald Freudenberger <freude@xxxxxxxxxxxxx>
The current AP bus, AP devices and AP device drivers implementation
uses a clearly defined mapping for binding AP devices to AP device
drivers. So for example a CEX6C queue will always be bound to the
cex4queue device driver.
The Linux Device Driver model has no sensitivity for more than one
device driver eligible for one device type. If there exist more than
one drivers matching to the device type, simple all drivers are tried
consecutively. There is no way to determine and influence the probing
order of the drivers.
With KVM there is a need to provide additional device drivers matching
to the very same type of AP devices. With a simple implementation the
KVM drivers run in competition to the regular drivers. Whichever
'wins' a device depends on build order and implementation details
within the common Linux Device Driver Model and is not
deterministic. However, a userspace process could figure out which
device should be bound to which driver and sort out the correct
binding by manipulating attributes in the sysfs.
If for security reasons a AP device must not get bound to the 'wrong'
device driver the sorting out has to be done within the Linux kernel
by the AP bus code. This patch modifies the behavior of the AP bus
for probing drivers for devices in a way that two sets of drivers are
usable. Two new bitmasks 'apmask' and 'aqmask' are used to mark a
subset of the APQN range for 'usable by the ap bus and the default
drivers' or 'not usable by the default drivers and thus available for
alternate drivers like vfio-xxx'. So an APQN which is addressed by
this masking only the default drivers will be probed. In contrary an
APQN which is not addressed by the masks will never be probed and
bound to default drivers but onny to alternate drivers.
Eventually the two masks give a way to divide the range of APQNs into
two pools: one pool of APQNs used by the AP bus and the default
drivers and thus via zcrypt drivers available to the userspace of the
system. And another pool where no zcrypt drivers are bound to and
which can be used by alternate drivers (like vfio-xxx) for their
needs. This division is hot-plug save and makes sure a APQN assigned
to an alternate driver is at no time somehow exploitable by the wrong
party.
For the first shot the two masks located in sysfs at
/sys/bus/ap/apmask and /sys/bus/ap/aqmask are read-only and by default
all APQNs belong to the ap bus and the default drivers:
cat /sys/bus/ap/apmask
0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
cat /sys/bus/ap/aqmask
0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
The only way to change these masks is currently via kernel command
line, for example like:
... ap.apmask=0xffff ap.aqmask=0x40
would give these two pools:
default drivers pool: adapter 0 - 15, domain 1
alternate drivers pool: adapter 0 - 15, all but domain 1
adapter 16-255, all domains
This patch will also be the base for an upcoming extension to the
zcrypt drivers to be able to provide additional zcrypt device nodes
with filtering based on ap and aq masks.
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Signed-off-by: Harald Freudenberger <freude@xxxxxxxxxxxxx>
---
drivers/s390/crypto/ap_bus.c | 158 ++++++++++++++++++++++++++--
drivers/s390/crypto/ap_bus.h | 28 +++++
drivers/s390/crypto/zcrypt_cex2a.c | 2 +
drivers/s390/crypto/zcrypt_cex4.c | 2 +
drivers/s390/crypto/zcrypt_pcixcc.c | 2 +
5 files changed, 186 insertions(+), 6 deletions(-)
diff --git a/drivers/s390/crypto/ap_bus.c b/drivers/s390/crypto/ap_bus.c
index c0a6723be54b..b36a4e17a734 100644
--- a/drivers/s390/crypto/ap_bus.c
+++ b/drivers/s390/crypto/ap_bus.c
@@ -34,6 +34,7 @@
#include <linux/crypto.h>
#include <linux/mod_devicetable.h>
#include <linux/debugfs.h>
+#include <linux/ctype.h>
#include "ap_bus.h"
#include "ap_debug.h"
@@ -51,11 +52,25 @@ static int ap_thread_flag = 0;
module_param_named(poll_thread, ap_thread_flag, int, S_IRUSR|S_IRGRP);
MODULE_PARM_DESC(poll_thread, "Turn on/off poll thread, default is 0 (off).");
+static char *apm_str;
+module_param_named(apmask, apm_str, charp, 0440);
+MODULE_PARM_DESC(apmask, "AP bus adapter mask.");
+
+static char *aqm_str;
+module_param_named(aqmask, aqm_str, charp, 0440);
+MODULE_PARM_DESC(aqmask, "AP bus domain mask.");
+
static struct device *ap_root_device;
DEFINE_SPINLOCK(ap_list_lock);
LIST_HEAD(ap_card_list);
+/* Default rights (card and domain masking) */
+static struct ap_rights {
+ DECLARE_BITMAP(apm, AP_DEVICES);
+ DECLARE_BITMAP(aqm, AP_DOMAINS);
+} ap_rights;
+
static struct ap_config_info *ap_configuration;
static bool initialised;
@@ -666,11 +681,57 @@ static struct bus_type ap_bus_type = {
.pm = &ap_bus_pm_ops,
};
+int ap_owned_by_def_drv(int card, int queue)
+{
+ int rc = 0;
+
+ if (card < 0 || card >= AP_DEVICES || queue < 0 || queue >= AP_DOMAINS)
+ return -EINVAL;
+
+ if (test_bit_inv(card, ap_rights.apm)
+ && test_bit_inv(queue, ap_rights.aqm))
+ rc = 1;
+
+ return rc;
+}
+EXPORT_SYMBOL(ap_owned_by_def_drv);
+
+int ap_apqn_in_matrix_owned_by_def_drv(unsigned long *apm, unsigned long *aqm)
+{
+ int card, queue, rc = 0;
+
+ for (card = 0; !rc && card < AP_DEVICES; card++)
+ if (test_bit_inv(card, apm) &&
+ test_bit_inv(card, ap_rights.apm))
+ for (queue = 0; !rc && queue < AP_DOMAINS; queue++)
+ if (test_bit_inv(queue, aqm) &&
+ test_bit_inv(queue, ap_rights.aqm))
+ rc = 1;
+
+ return rc;
+}
+EXPORT_SYMBOL(ap_apqn_in_matrix_owned_by_def_drv);
+
static int ap_device_probe(struct device *dev)
{
struct ap_device *ap_dev = to_ap_dev(dev);
struct ap_driver *ap_drv = to_ap_drv(dev->driver);
- int rc;
+ int card, queue, devres, drvres, rc;
+
+ if (is_queue_dev(dev)) {
+ /*
+ * For apqns marked as reserved/used by ap bus and
+ * default drivers only drivers with a default flag
+ * will be called for probe this device.
+ */
+ card = AP_QID_CARD(to_ap_queue(dev)->qid);
+ queue = AP_QID_QUEUE(to_ap_queue(dev)->qid);
+ devres = test_bit_inv(card, ap_rights.apm)
+ && test_bit_inv(queue, ap_rights.aqm);
+ drvres = ap_drv->flags & AP_DRIVER_FLAG_DEFAULT;
+ if ((devres && !drvres) || (!devres && drvres))
+ return -ENODEV;
+ }
/* Add queue/card to list of active queues/cards */
spin_lock_bh(&ap_list_lock);
@@ -753,6 +814,32 @@ EXPORT_SYMBOL(ap_bus_force_rescan);
/*
* AP bus attributes.
*/
+
+static int hex2bitmap(const char *str, unsigned long *bitmap, int bits)
+{
+ int i, n, b;
+
+ memset(bitmap, 0, bits / 8);
+
+ if (str[0] == '0' && str[1] == 'x')
+ str++;
+ if (*str == 'x')
+ str++;
+
+ for (i = 0; isxdigit(*str) && i < bits; str++) {
+ b = hex_to_bin(*str);
+ for (n = 0; n < 4; n++)
+ if (b & (0x08 >> n))
+ set_bit_inv(i + n, bitmap);
+ i += 4;
+ }
+
+ if (i < 4 || isxdigit(*str))
+ return -EINVAL;
+
+ return 0;
+}
+
static ssize_t ap_domain_show(struct bus_type *bus, char *buf)
{
return snprintf(buf, PAGE_SIZE, "%d\n", ap_domain_index);
@@ -764,7 +851,8 @@ static ssize_t ap_domain_store(struct bus_type *bus,
int domain;
if (sscanf(buf, "%i\n", &domain) != 1 ||
- domain < 0 || domain > ap_max_domain_id)
+ domain < 0 || domain > ap_max_domain_id ||
+ !test_bit_inv(domain, ap_rights.aqm))
return -EINVAL;
spin_lock_bh(&ap_domain_lock);
ap_domain_index = domain;
@@ -901,6 +989,26 @@ static ssize_t ap_max_domain_id_show(struct bus_type *bus, char *buf)
static BUS_ATTR(ap_max_domain_id, 0444, ap_max_domain_id_show, NULL);
+static ssize_t ap_apmask_show(struct bus_type *bus, char *buf)
+{
+ return snprintf(buf, PAGE_SIZE,
+ "0x%016lx%016lx%016lx%016lx\n",
+ ap_rights.apm[0], ap_rights.apm[1],
+ ap_rights.apm[2], ap_rights.apm[3]);
+}
+
+static BUS_ATTR(apmask, 0444, ap_apmask_show, NULL);
+
+static ssize_t ap_aqmask_show(struct bus_type *bus, char *buf)
+{
+ return snprintf(buf, PAGE_SIZE,
+ "0x%016lx%016lx%016lx%016lx\n",
+ ap_rights.aqm[0], ap_rights.aqm[1],
+ ap_rights.aqm[2], ap_rights.aqm[3]);
+}
+
+static BUS_ATTR(aqmask, 0444, ap_aqmask_show, NULL);
+
static struct bus_attribute *const ap_bus_attrs[] = {
&bus_attr_ap_domain,
&bus_attr_ap_control_domain_mask,
@@ -910,6 +1018,8 @@ static struct bus_attribute *const ap_bus_attrs[] = {
&bus_attr_ap_interrupts,
&bus_attr_poll_timeout,
&bus_attr_ap_max_domain_id,
+ &bus_attr_apmask,
+ &bus_attr_aqmask,
NULL,
};
@@ -938,7 +1048,8 @@ static int ap_select_domain(void)
best_domain = -1;
max_count = 0;
for (i = 0; i < AP_DOMAINS; i++) {
- if (!ap_test_config_domain(i))
+ if (!ap_test_config_domain(i) ||
+ !test_bit_inv(i, ap_rights.aqm))
continue;
count = 0;
for (j = 0; j < AP_DEVICES; j++) {
@@ -1042,7 +1153,7 @@ static void ap_scan_bus(struct work_struct *unused)
ap_query_configuration(ap_configuration);
if (ap_select_domain() != 0)
- goto out;
+ AP_DBF(DBF_INFO, "ap_domain_index=%d\n", ap_domain_index);
for (id = 0; id < AP_DEVICES; id++) {
/* check if device is registered */
@@ -1166,7 +1277,6 @@ static void ap_scan_bus(struct work_struct *unused)
AP_DBF(DBF_INFO, "no queue device with default domain %d available\n",
ap_domain_index);
-out:
mod_timer(&ap_config_timer, jiffies + ap_config_time * HZ);
}
@@ -1187,6 +1297,37 @@ static int __init ap_debug_init(void)
return 0;
}
+static void __init ap_rights_init(void)
+{
+ int i, rc;
+
+ /* start with all resources useable */
+ memset(&ap_rights.apm, 0xFF, sizeof(ap_rights.apm));
+ memset(&ap_rights.aqm, 0xFF, sizeof(ap_rights.aqm));
+
+ /* process kernel parameters apm and aqm if given */
+ if (apm_str) {
+ DECLARE_BITMAP(apm, AP_DEVICES);
+
+ rc = hex2bitmap(apm_str, apm, AP_DEVICES);
+ if (rc == 0) {
+ for (i = 0; i < AP_DEVICES; i++)
+ if (!test_bit_inv(i, apm))
+ clear_bit_inv(i, ap_rights.apm);
+ }
+ }
+ if (aqm_str) {
+ DECLARE_BITMAP(aqm, AP_DOMAINS);
+
+ rc = hex2bitmap(aqm_str, aqm, AP_DOMAINS);
+ if (rc == 0) {
+ for (i = 0; i < AP_DOMAINS; i++)
+ if (!test_bit_inv(i, aqm))
+ clear_bit_inv(i, ap_rights.aqm);
+ }
+ }
+}
+
/**
* ap_module_init(): The module initialization code.
*
@@ -1206,6 +1347,9 @@ static int __init ap_module_init(void)
return -ENODEV;
}
+ /* set up the AP rights (ap and aq masks) */
+ ap_rights_init();
+
/* Get AP configuration data if available */
ap_init_configuration();
@@ -1214,7 +1358,9 @@ static int __init ap_module_init(void)
ap_max_domain_id ? ap_max_domain_id : AP_DOMAINS - 1;
else
max_domain_id = 15;
- if (ap_domain_index < -1 || ap_domain_index > max_domain_id) {
+ if (ap_domain_index < -1 || ap_domain_index > max_domain_id ||
+ (ap_domain_index >= 0 &&
+ !test_bit_inv(ap_domain_index, ap_rights.aqm))) {
pr_warn("%d is not a valid cryptographic domain\n",
ap_domain_index);
ap_domain_index = -1;
diff --git a/drivers/s390/crypto/ap_bus.h b/drivers/s390/crypto/ap_bus.h
index 936541937e15..2e848c5fedba 100644
--- a/drivers/s390/crypto/ap_bus.h
+++ b/drivers/s390/crypto/ap_bus.h
@@ -117,9 +117,18 @@ enum ap_wait {
struct ap_device;
struct ap_message;
+/*
+ * The ap driver struct includes a flags field which holds some info for
+ * the ap bus about the driver. Currently only one flag is supported and
+ * used: The DEFAULT flag marks an ap driver as a default driver which is
+ * used together with the apmask and aqmask whitelisting of the ap bus.
+ */
+#define AP_DRIVER_FLAG_DEFAULT 0x0001
+
struct ap_driver {
struct device_driver driver;
struct ap_device_id *ids;
+ unsigned int flags;
int (*probe)(struct ap_device *);
void (*remove)(struct ap_device *);
@@ -248,4 +257,23 @@ void ap_queue_resume(struct ap_device *ap_dev);
struct ap_card *ap_card_create(int id, int queue_depth, int raw_device_type,
int comp_device_type, unsigned int functions);
+/*
+ * check APQN for owned/reserved by ap bus and default driver(s).
+ * Checks if this APQN is or will be in use by the ap bus
+ * and the default set of drivers.
+ * If yes, returns 1, if not returns 0. On error a negative
+ * errno value is returned.
+ */
+int ap_owned_by_def_drv(int card, int queue);
+
+/*
+ * check 'matrix' of APQNs for owned/reserved by ap bus and
+ * default driver(s).
+ * Checks if there is at least one APQN in the given 'matrix'
+ * marked as owned/reserved by the ap bus and default driver(s).
+ * If such an APQN is found the return value is 1, otherwise
+ * 0 is returned. On error a negative errno value is returned.
+ */
+int ap_apqn_in_matrix_owned_by_def_drv(unsigned long *, unsigned long *);
+
#endif /* _AP_BUS_H_ */
diff --git a/drivers/s390/crypto/zcrypt_cex2a.c b/drivers/s390/crypto/zcrypt_cex2a.c
index e701194d3611..f4ae5fa30ec9 100644
--- a/drivers/s390/crypto/zcrypt_cex2a.c
+++ b/drivers/s390/crypto/zcrypt_cex2a.c
@@ -145,6 +145,7 @@ static struct ap_driver zcrypt_cex2a_card_driver = {
.probe = zcrypt_cex2a_card_probe,
.remove = zcrypt_cex2a_card_remove,
.ids = zcrypt_cex2a_card_ids,
+ .flags = AP_DRIVER_FLAG_DEFAULT,
};
/**
@@ -208,6 +209,7 @@ static struct ap_driver zcrypt_cex2a_queue_driver = {
.suspend = ap_queue_suspend,
.resume = ap_queue_resume,
.ids = zcrypt_cex2a_queue_ids,
+ .flags = AP_DRIVER_FLAG_DEFAULT,
};
int __init zcrypt_cex2a_init(void)
diff --git a/drivers/s390/crypto/zcrypt_cex4.c b/drivers/s390/crypto/zcrypt_cex4.c
index f305538334ad..35d58dbbc4da 100644
--- a/drivers/s390/crypto/zcrypt_cex4.c
+++ b/drivers/s390/crypto/zcrypt_cex4.c
@@ -214,6 +214,7 @@ static struct ap_driver zcrypt_cex4_card_driver = {
.probe = zcrypt_cex4_card_probe,
.remove = zcrypt_cex4_card_remove,
.ids = zcrypt_cex4_card_ids,
+ .flags = AP_DRIVER_FLAG_DEFAULT,
};
/**
@@ -283,6 +284,7 @@ static struct ap_driver zcrypt_cex4_queue_driver = {
.suspend = ap_queue_suspend,
.resume = ap_queue_resume,
.ids = zcrypt_cex4_queue_ids,
+ .flags = AP_DRIVER_FLAG_DEFAULT,
};
int __init zcrypt_cex4_init(void)
diff --git a/drivers/s390/crypto/zcrypt_pcixcc.c b/drivers/s390/crypto/zcrypt_pcixcc.c
index 159b0a0dd211..e5e14d723163 100644
--- a/drivers/s390/crypto/zcrypt_pcixcc.c
+++ b/drivers/s390/crypto/zcrypt_pcixcc.c
@@ -223,6 +223,7 @@ static struct ap_driver zcrypt_pcixcc_card_driver = {
.probe = zcrypt_pcixcc_card_probe,
.remove = zcrypt_pcixcc_card_remove,
.ids = zcrypt_pcixcc_card_ids,
+ .flags = AP_DRIVER_FLAG_DEFAULT,
};
/**
@@ -286,6 +287,7 @@ static struct ap_driver zcrypt_pcixcc_queue_driver = {
.suspend = ap_queue_suspend,
.resume = ap_queue_resume,
.ids = zcrypt_pcixcc_queue_ids,
+ .flags = AP_DRIVER_FLAG_DEFAULT,
};
int __init zcrypt_pcixcc_init(void)
--
2.17.0
