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Tue, 24 Nov 2020 21:40:33 +0000 (GMT) Received: from b01ledav005.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3E433AE05C; Tue, 24 Nov 2020 21:40:32 +0000 (GMT) Received: from cpe-66-24-58-13.stny.res.rr.com.com (unknown [9.85.195.249]) by b01ledav005.gho.pok.ibm.com (Postfix) with ESMTP; Tue, 24 Nov 2020 21:40:32 +0000 (GMT) From: Tony Krowiak To: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: freude@linux.ibm.com, borntraeger@de.ibm.com, cohuck@redhat.com, mjrosato@linux.ibm.com, pasic@linux.ibm.com, alex.williamson@redhat.com, kwankhede@nvidia.com, fiuczy@linux.ibm.com, frankja@linux.ibm.com, david@redhat.com, hca@linux.ibm.com, gor@linux.ibm.com, Tony Krowiak Subject: [PATCH v12 06/17] s390/zcrypt: driver callback to indicate resource in use Date: Tue, 24 Nov 2020 16:40:05 -0500 Message-Id: <20201124214016.3013-7-akrowiak@linux.ibm.com> X-Mailer: git-send-email 2.21.1 In-Reply-To: <20201124214016.3013-1-akrowiak@linux.ibm.com> References: <20201124214016.3013-1-akrowiak@linux.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.312,18.0.737 definitions=2020-11-24_08:2020-11-24,2020-11-24 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 lowpriorityscore=0 malwarescore=0 phishscore=0 spamscore=0 suspectscore=3 clxscore=1015 mlxlogscore=999 priorityscore=1501 adultscore=0 bulkscore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011240125 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Introduces a new driver callback to prevent a root user from unbinding an AP queue from its device driver if the queue is in use. The callback will be invoked whenever a change to the AP bus's sysfs apmask or aqmask attributes would result in one or more AP queues being removed from its driver. If the callback responds in the affirmative for any driver queried, the change to the apmask or aqmask will be rejected with a device busy error. For this patch, only non-default drivers will be queried. Currently, there is only one non-default driver, the vfio_ap device driver. The vfio_ap device driver facilitates pass-through of an AP queue to a guest. The idea here is that a guest may be administered by a different sysadmin than the host and we don't want AP resources to unexpectedly disappear from a guest's AP configuration (i.e., adapters and domains assigned to the matrix mdev). This will enforce the proper procedure for removing AP resources intended for guest usage which is to first unassign them from the matrix mdev, then unbind them from the vfio_ap device driver. Signed-off-by: Tony Krowiak Reviewed-by: Harald Freudenberger --- drivers/s390/crypto/ap_bus.c | 160 ++++++++++++++++++++++++++++++++--- drivers/s390/crypto/ap_bus.h | 4 + 2 files changed, 154 insertions(+), 10 deletions(-) diff --git a/drivers/s390/crypto/ap_bus.c b/drivers/s390/crypto/ap_bus.c index ef738b42a092..593573740981 100644 --- a/drivers/s390/crypto/ap_bus.c +++ b/drivers/s390/crypto/ap_bus.c @@ -35,6 +35,7 @@ #include #include #include +#include #include "ap_bus.h" #include "ap_debug.h" @@ -901,6 +902,23 @@ static int modify_bitmap(const char *str, unsigned long *bitmap, int bits) return 0; } +static int ap_parse_bitmap_str(const char *str, unsigned long *bitmap, int bits, + unsigned long *newmap) +{ + unsigned long size; + int rc; + + size = BITS_TO_LONGS(bits)*sizeof(unsigned long); + if (*str == '+' || *str == '-') { + memcpy(newmap, bitmap, size); + rc = modify_bitmap(str, newmap, bits); + } else { + memset(newmap, 0, size); + rc = hex2bitmap(str, newmap, bits); + } + return rc; +} + int ap_parse_mask_str(const char *str, unsigned long *bitmap, int bits, struct mutex *lock) @@ -920,14 +938,7 @@ int ap_parse_mask_str(const char *str, kfree(newmap); return -ERESTARTSYS; } - - if (*str == '+' || *str == '-') { - memcpy(newmap, bitmap, size); - rc = modify_bitmap(str, newmap, bits); - } else { - memset(newmap, 0, size); - rc = hex2bitmap(str, newmap, bits); - } + rc = ap_parse_bitmap_str(str, bitmap, bits, newmap); if (rc == 0) memcpy(bitmap, newmap, size); mutex_unlock(lock); @@ -1119,12 +1130,76 @@ static ssize_t apmask_show(struct bus_type *bus, char *buf) return rc; } +static int __verify_card_reservations(struct device_driver *drv, void *data) +{ + int rc = 0; + struct ap_driver *ap_drv = to_ap_drv(drv); + unsigned long *newapm = (unsigned long *)data; + + /* + * No need to verify whether the driver is using the queues if it is the + * default driver. + */ + if (ap_drv->flags & AP_DRIVER_FLAG_DEFAULT) + return 0; + + /* + * increase the driver's module refcounter to be sure it is not + * going away when we invoke the callback function. + */ + if (!try_module_get(drv->owner)) + return 0; + + if (ap_drv->in_use) { + rc = ap_drv->in_use(newapm, ap_perms.aqm); + if (rc) + return rc; + } + + /* release the driver's module */ + module_put(drv->owner); + + return rc; +} + +static int apmask_commit(unsigned long *newapm) +{ + int rc; + unsigned long reserved[BITS_TO_LONGS(AP_DEVICES)]; + + /* + * Check if any bits in the apmask have been set which will + * result in queues being removed from non-default drivers + */ + if (bitmap_andnot(reserved, newapm, ap_perms.apm, AP_DEVICES)) { + rc = bus_for_each_drv(&ap_bus_type, NULL, reserved, + __verify_card_reservations); + if (rc) + return rc; + } + + memcpy(ap_perms.apm, newapm, APMASKSIZE); + + return 0; +} + static ssize_t apmask_store(struct bus_type *bus, const char *buf, size_t count) { int rc; + DECLARE_BITMAP(newapm, AP_DEVICES); + + if (mutex_lock_interruptible(&ap_perms_mutex)) + return -ERESTARTSYS; - rc = ap_parse_mask_str(buf, ap_perms.apm, AP_DEVICES, &ap_perms_mutex); + rc = ap_parse_bitmap_str(buf, ap_perms.apm, AP_DEVICES, newapm); + if (rc) + goto done; + + rc = apmask_commit(newapm); + +done: + mutex_unlock(&ap_perms_mutex); if (rc) return rc; @@ -1150,12 +1225,77 @@ static ssize_t aqmask_show(struct bus_type *bus, char *buf) return rc; } +static int __verify_queue_reservations(struct device_driver *drv, void *data) +{ + int rc = 0; + struct ap_driver *ap_drv = to_ap_drv(drv); + unsigned long *newaqm = (unsigned long *)data; + + /* + * If the reserved bits do not identify queues reserved for use by the + * non-default driver, there is no need to verify the driver is using + * the queues. + */ + if (ap_drv->flags & AP_DRIVER_FLAG_DEFAULT) + return 0; + + /* + * increase the driver's module refcounter to be sure it is not + * going away when we invoke the callback function. + */ + if (!try_module_get(drv->owner)) + return 0; + + if (ap_drv->in_use) { + rc = ap_drv->in_use(ap_perms.apm, newaqm); + if (rc) + return rc; + } + + /* release the driver's module */ + module_put(drv->owner); + + return rc; +} + +static int aqmask_commit(unsigned long *newaqm) +{ + int rc; + unsigned long reserved[BITS_TO_LONGS(AP_DOMAINS)]; + + /* + * Check if any bits in the aqmask have been set which will + * result in queues being removed from non-default drivers + */ + if (bitmap_andnot(reserved, newaqm, ap_perms.aqm, AP_DOMAINS)) { + rc = bus_for_each_drv(&ap_bus_type, NULL, reserved, + __verify_queue_reservations); + if (rc) + return rc; + } + + memcpy(ap_perms.aqm, newaqm, AQMASKSIZE); + + return 0; +} + static ssize_t aqmask_store(struct bus_type *bus, const char *buf, size_t count) { int rc; + DECLARE_BITMAP(newaqm, AP_DOMAINS); + + if (mutex_lock_interruptible(&ap_perms_mutex)) + return -ERESTARTSYS; + + rc = ap_parse_bitmap_str(buf, ap_perms.aqm, AP_DOMAINS, newaqm); + if (rc) + goto done; + + rc = aqmask_commit(newaqm); - rc = ap_parse_mask_str(buf, ap_perms.aqm, AP_DOMAINS, &ap_perms_mutex); +done: + mutex_unlock(&ap_perms_mutex); if (rc) return rc; diff --git a/drivers/s390/crypto/ap_bus.h b/drivers/s390/crypto/ap_bus.h index 5029b80132aa..65edd847c65a 100644 --- a/drivers/s390/crypto/ap_bus.h +++ b/drivers/s390/crypto/ap_bus.h @@ -145,6 +145,7 @@ struct ap_driver { int (*probe)(struct ap_device *); void (*remove)(struct ap_device *); + int (*in_use)(unsigned long *apm, unsigned long *aqm); }; #define to_ap_drv(x) container_of((x), struct ap_driver, driver) @@ -293,6 +294,9 @@ void ap_queue_init_state(struct ap_queue *aq); struct ap_card *ap_card_create(int id, int queue_depth, int raw_device_type, int comp_device_type, unsigned int functions); +#define APMASKSIZE (BITS_TO_LONGS(AP_DEVICES) * sizeof(unsigned long)) +#define AQMASKSIZE (BITS_TO_LONGS(AP_DOMAINS) * sizeof(unsigned long)) + struct ap_perms { unsigned long ioctlm[BITS_TO_LONGS(AP_IOCTLS)]; unsigned long apm[BITS_TO_LONGS(AP_DEVICES)]; -- 2.21.1