![Harald Freudenberger](/assets/img/avatar_default.png)
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. The two masks are located in sysfs at /sys/bus/ap/apmask and /sys/bus/ap/aqmask. The mask syntax is exactly the same as the already existing mask attributes in the /sys/bus/ap directory (for example ap_usage_domain_mask and ap_control_domain_mask). 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 masks can be changed at boot time with the kernel command line like this: ... ap.apmask=0xffff ap.aqmask=0x40 This 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 The sysfs attributes for this two masks are writeable and an administrator is able to reconfigure the assignements on the fly by writing new mask values into. With changing the mask(s) a revision of the existing queue to driver bindings is done. So all APQNs which are bound to the 'wrong' driver are reprobed via kernel function device_reprobe() and thus the new correct driver will be assigned with respect of the changed apmask and aqmask bits. The mask values are bitmaps in big endian order starting with bit 0. So adapter number 0 is the leftmost bit, mask is 0x8000... The sysfs attributes accept 2 different formats: - Absolute hex string starting with 0x like "0x12345678" does set the mask starting from left to right. If the given string is shorter than the mask it is padded with 0s on the right. If the string is longer than the mask an error comes back (EINVAL). - '+' or '-' followed by a numerical value. Valid examples are "+1", "-13", "+0x41", "-0xff" and even "+0" and "-0". Only the addressed bit in the mask is switched on ('+') or off ('-'). 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: Harald Freudenberger <freude@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
318 lines
8.2 KiB
C
318 lines
8.2 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* zcrypt 2.1.0
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*
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* Copyright IBM Corp. 2001, 2012
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* Author(s): Robert Burroughs
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* Eric Rossman (edrossma@us.ibm.com)
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*
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* Hotplug & misc device support: Jochen Roehrig (roehrig@de.ibm.com)
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* Major cleanup & driver split: Martin Schwidefsky <schwidefsky@de.ibm.com>
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* Ralph Wuerthner <rwuerthn@de.ibm.com>
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* MSGTYPE restruct: Holger Dengler <hd@linux.vnet.ibm.com>
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/err.h>
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#include <linux/delay.h>
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#include <linux/slab.h>
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#include <linux/atomic.h>
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#include <linux/uaccess.h>
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#include <linux/mod_devicetable.h>
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#include "ap_bus.h"
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#include "zcrypt_api.h"
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#include "zcrypt_error.h"
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#include "zcrypt_msgtype6.h"
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#include "zcrypt_pcixcc.h"
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#include "zcrypt_cca_key.h"
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#define PCIXCC_MIN_MOD_SIZE 16 /* 128 bits */
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#define PCIXCC_MIN_MOD_SIZE_OLD 64 /* 512 bits */
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#define PCIXCC_MAX_MOD_SIZE 256 /* 2048 bits */
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#define CEX3C_MIN_MOD_SIZE PCIXCC_MIN_MOD_SIZE
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#define CEX3C_MAX_MOD_SIZE 512 /* 4096 bits */
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#define PCIXCC_MAX_ICA_MESSAGE_SIZE 0x77c /* max size type6 v2 crt message */
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#define PCIXCC_MAX_ICA_RESPONSE_SIZE 0x77c /* max size type86 v2 reply */
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#define PCIXCC_MAX_XCRB_MESSAGE_SIZE (12*1024)
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#define PCIXCC_CLEANUP_TIME (15*HZ)
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#define CEIL4(x) ((((x)+3)/4)*4)
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struct response_type {
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struct completion work;
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int type;
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};
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#define PCIXCC_RESPONSE_TYPE_ICA 0
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#define PCIXCC_RESPONSE_TYPE_XCRB 1
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MODULE_AUTHOR("IBM Corporation");
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MODULE_DESCRIPTION("PCIXCC Cryptographic Coprocessor device driver, " \
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"Copyright IBM Corp. 2001, 2012");
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MODULE_LICENSE("GPL");
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static struct ap_device_id zcrypt_pcixcc_card_ids[] = {
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{ .dev_type = AP_DEVICE_TYPE_PCIXCC,
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.match_flags = AP_DEVICE_ID_MATCH_CARD_TYPE },
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{ .dev_type = AP_DEVICE_TYPE_CEX2C,
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.match_flags = AP_DEVICE_ID_MATCH_CARD_TYPE },
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{ .dev_type = AP_DEVICE_TYPE_CEX3C,
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.match_flags = AP_DEVICE_ID_MATCH_CARD_TYPE },
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{ /* end of list */ },
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};
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MODULE_DEVICE_TABLE(ap, zcrypt_pcixcc_card_ids);
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static struct ap_device_id zcrypt_pcixcc_queue_ids[] = {
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{ .dev_type = AP_DEVICE_TYPE_PCIXCC,
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.match_flags = AP_DEVICE_ID_MATCH_QUEUE_TYPE },
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{ .dev_type = AP_DEVICE_TYPE_CEX2C,
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.match_flags = AP_DEVICE_ID_MATCH_QUEUE_TYPE },
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{ .dev_type = AP_DEVICE_TYPE_CEX3C,
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.match_flags = AP_DEVICE_ID_MATCH_QUEUE_TYPE },
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{ /* end of list */ },
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};
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MODULE_DEVICE_TABLE(ap, zcrypt_pcixcc_queue_ids);
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/**
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* Large random number detection function. Its sends a message to a pcixcc
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* card to find out if large random numbers are supported.
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* @ap_dev: pointer to the AP device.
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*
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* Returns 1 if large random numbers are supported, 0 if not and < 0 on error.
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*/
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static int zcrypt_pcixcc_rng_supported(struct ap_queue *aq)
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{
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struct ap_message ap_msg;
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unsigned long long psmid;
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unsigned int domain;
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struct {
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struct type86_hdr hdr;
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struct type86_fmt2_ext fmt2;
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struct CPRBX cprbx;
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} __packed *reply;
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struct {
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struct type6_hdr hdr;
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struct CPRBX cprbx;
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char function_code[2];
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short int rule_length;
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char rule[8];
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short int verb_length;
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short int key_length;
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} __packed *msg;
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int rc, i;
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ap_init_message(&ap_msg);
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ap_msg.message = (void *) get_zeroed_page(GFP_KERNEL);
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if (!ap_msg.message)
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return -ENOMEM;
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rng_type6CPRB_msgX(&ap_msg, 4, &domain);
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msg = ap_msg.message;
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msg->cprbx.domain = AP_QID_QUEUE(aq->qid);
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rc = ap_send(aq->qid, 0x0102030405060708ULL, ap_msg.message,
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ap_msg.length);
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if (rc)
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goto out_free;
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/* Wait for the test message to complete. */
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for (i = 0; i < 2 * HZ; i++) {
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msleep(1000 / HZ);
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rc = ap_recv(aq->qid, &psmid, ap_msg.message, 4096);
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if (rc == 0 && psmid == 0x0102030405060708ULL)
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break;
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}
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if (i >= 2 * HZ) {
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/* Got no answer. */
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rc = -ENODEV;
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goto out_free;
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}
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reply = ap_msg.message;
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if (reply->cprbx.ccp_rtcode == 0 && reply->cprbx.ccp_rscode == 0)
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rc = 1;
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else
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rc = 0;
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out_free:
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free_page((unsigned long) ap_msg.message);
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return rc;
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}
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/**
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* Probe function for PCIXCC/CEX2C card devices. It always accepts the
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* AP device since the bus_match already checked the hardware type. The
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* PCIXCC cards come in two flavours: micro code level 2 and micro code
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* level 3. This is checked by sending a test message to the device.
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* @ap_dev: pointer to the AP card device.
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*/
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static int zcrypt_pcixcc_card_probe(struct ap_device *ap_dev)
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{
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/*
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* Normalized speed ratings per crypto adapter
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* MEX_1k, MEX_2k, MEX_4k, CRT_1k, CRT_2k, CRT_4k, RNG, SECKEY
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*/
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static const int CEX2C_SPEED_IDX[] = {
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1000, 1400, 2400, 1100, 1500, 2600, 100, 12};
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static const int CEX3C_SPEED_IDX[] = {
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500, 700, 1400, 550, 800, 1500, 80, 10};
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struct ap_card *ac = to_ap_card(&ap_dev->device);
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struct zcrypt_card *zc;
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int rc = 0;
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zc = zcrypt_card_alloc();
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if (!zc)
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return -ENOMEM;
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zc->card = ac;
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ac->private = zc;
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switch (ac->ap_dev.device_type) {
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case AP_DEVICE_TYPE_CEX2C:
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zc->user_space_type = ZCRYPT_CEX2C;
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zc->type_string = "CEX2C";
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memcpy(zc->speed_rating, CEX2C_SPEED_IDX,
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sizeof(CEX2C_SPEED_IDX));
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zc->min_mod_size = PCIXCC_MIN_MOD_SIZE;
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zc->max_mod_size = PCIXCC_MAX_MOD_SIZE;
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zc->max_exp_bit_length = PCIXCC_MAX_MOD_SIZE;
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break;
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case AP_DEVICE_TYPE_CEX3C:
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zc->user_space_type = ZCRYPT_CEX3C;
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zc->type_string = "CEX3C";
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memcpy(zc->speed_rating, CEX3C_SPEED_IDX,
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sizeof(CEX3C_SPEED_IDX));
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zc->min_mod_size = CEX3C_MIN_MOD_SIZE;
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zc->max_mod_size = CEX3C_MAX_MOD_SIZE;
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zc->max_exp_bit_length = CEX3C_MAX_MOD_SIZE;
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break;
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default:
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zcrypt_card_free(zc);
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return -ENODEV;
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}
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zc->online = 1;
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rc = zcrypt_card_register(zc);
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if (rc) {
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ac->private = NULL;
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zcrypt_card_free(zc);
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}
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return rc;
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}
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/**
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* This is called to remove the PCIXCC/CEX2C card driver information
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* if an AP card device is removed.
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*/
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static void zcrypt_pcixcc_card_remove(struct ap_device *ap_dev)
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{
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struct zcrypt_card *zc = to_ap_card(&ap_dev->device)->private;
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if (zc)
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zcrypt_card_unregister(zc);
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}
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static struct ap_driver zcrypt_pcixcc_card_driver = {
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.probe = zcrypt_pcixcc_card_probe,
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.remove = zcrypt_pcixcc_card_remove,
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.ids = zcrypt_pcixcc_card_ids,
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.flags = AP_DRIVER_FLAG_DEFAULT,
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};
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/**
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* Probe function for PCIXCC/CEX2C queue devices. It always accepts the
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* AP device since the bus_match already checked the hardware type. The
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* PCIXCC cards come in two flavours: micro code level 2 and micro code
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* level 3. This is checked by sending a test message to the device.
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* @ap_dev: pointer to the AP card device.
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*/
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static int zcrypt_pcixcc_queue_probe(struct ap_device *ap_dev)
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{
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struct ap_queue *aq = to_ap_queue(&ap_dev->device);
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struct zcrypt_queue *zq;
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int rc;
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zq = zcrypt_queue_alloc(PCIXCC_MAX_XCRB_MESSAGE_SIZE);
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if (!zq)
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return -ENOMEM;
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zq->queue = aq;
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zq->online = 1;
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atomic_set(&zq->load, 0);
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rc = zcrypt_pcixcc_rng_supported(aq);
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if (rc < 0) {
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zcrypt_queue_free(zq);
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return rc;
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}
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if (rc)
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zq->ops = zcrypt_msgtype(MSGTYPE06_NAME,
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MSGTYPE06_VARIANT_DEFAULT);
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else
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zq->ops = zcrypt_msgtype(MSGTYPE06_NAME,
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MSGTYPE06_VARIANT_NORNG);
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ap_queue_init_reply(aq, &zq->reply);
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aq->request_timeout = PCIXCC_CLEANUP_TIME,
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aq->private = zq;
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rc = zcrypt_queue_register(zq);
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if (rc) {
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aq->private = NULL;
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zcrypt_queue_free(zq);
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}
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return rc;
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}
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/**
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* This is called to remove the PCIXCC/CEX2C queue driver information
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* if an AP queue device is removed.
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*/
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static void zcrypt_pcixcc_queue_remove(struct ap_device *ap_dev)
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{
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struct ap_queue *aq = to_ap_queue(&ap_dev->device);
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struct zcrypt_queue *zq = aq->private;
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ap_queue_remove(aq);
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if (zq)
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zcrypt_queue_unregister(zq);
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}
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static struct ap_driver zcrypt_pcixcc_queue_driver = {
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.probe = zcrypt_pcixcc_queue_probe,
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.remove = zcrypt_pcixcc_queue_remove,
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.suspend = ap_queue_suspend,
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.resume = ap_queue_resume,
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.ids = zcrypt_pcixcc_queue_ids,
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.flags = AP_DRIVER_FLAG_DEFAULT,
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};
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int __init zcrypt_pcixcc_init(void)
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{
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int rc;
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rc = ap_driver_register(&zcrypt_pcixcc_card_driver,
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THIS_MODULE, "pcixcccard");
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if (rc)
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return rc;
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rc = ap_driver_register(&zcrypt_pcixcc_queue_driver,
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THIS_MODULE, "pcixccqueue");
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if (rc)
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ap_driver_unregister(&zcrypt_pcixcc_card_driver);
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return rc;
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}
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void zcrypt_pcixcc_exit(void)
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{
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ap_driver_unregister(&zcrypt_pcixcc_queue_driver);
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ap_driver_unregister(&zcrypt_pcixcc_card_driver);
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}
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module_init(zcrypt_pcixcc_init);
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module_exit(zcrypt_pcixcc_exit);
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