[PATCH net-next 4/4] s390/qeth: use diag26c to get MAC address on L2

Julian Wiedmann
2017-06-19T11:22:25Z

When a s390 guest runs on a z/VM host that's part of a SSI cluster,
it can be migrated to a different host. In this case, the MAC address
it originally obtained on the old host may be re-assigned to a new
guest. This would result in address conflicts between the two guests.

When running as z/VM guest, use the diag26c MAC Service to obtain
a hypervisor-managed MAC address. The MAC Service is SSI-aware, and
won't re-assign the address after the guest is migrated to a new host.

This patch adds support for the z/VM MAC Service on L2 devices.

Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com>
Acked-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
---
drivers/s390/net/qeth_core.h | 1 +
drivers/s390/net/qeth_core_main.c | 61 +++++++++++++++++++++++++++++++++++++++
drivers/s390/net/qeth_l2_main.c | 16 ++++++++--
3 files changed, 76 insertions(+), 2 deletions(-)

diff --git a/drivers/s390/net/qeth_core.h b/drivers/s390/net/qeth_core.h
index 0efc54a4d82f..7a0ffc71b25d 100644
--- a/drivers/s390/net/qeth_core.h
+++ b/drivers/s390/net/qeth_core.h
@@ -986,6 +986,7 @@ struct qeth_cmd_buffer *qeth_get_setassparms_cmd(struct qeth_card *,
int qeth_set_features(struct net_device *, netdev_features_t);
int qeth_recover_features(struct net_device *);
netdev_features_t qeth_fix_features(struct net_device *, netdev_features_t);
+int qeth_vm_request_mac(struct qeth_card *card);

/* exports for OSN */
int qeth_osn_assist(struct net_device *, void *, int);
diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index 13a55f1dee7a..1d062f086744 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -27,6 +27,9 @@
#include <asm/io.h>
#include <asm/sysinfo.h>
#include <asm/compat.h>
+#include <asm/diag.h>
+#include <asm/cio.h>
+#include <asm/ccwdev.h>

#include "qeth_core.h"

@@ -4773,6 +4776,64 @@ static int qeth_query_card_info(struct qeth_card *card,
(void *)carrier_info);
}

+/**
+ * qeth_vm_request_mac() - Request a hypervisor-managed MAC address
+ * @card: pointer to a qeth_card
+ *
+ * Returns
+ * 0, if a MAC address has been set for the card's netdevice
+ * a return code, for various error conditions
+ */
+int qeth_vm_request_mac(struct qeth_card *card)
+{
+ struct diag26c_mac_req *request;
+ struct diag26c_mac_resp *response;
+ struct ccw_dev_id id;
+ int rc;
+
+ QETH_DBF_TEXT(SETUP, 2, "vmreqmac");
+
+ if (!card->dev)
+ return -ENODEV;
+
+ request = kzalloc(sizeof(*request), GFP_KERNEL | GFP_DMA);
+ response = kzalloc(sizeof(*response), GFP_KERNEL | GFP_DMA);
+ if (!request || !response) {
+ rc = -ENOMEM;
+ goto out;
+ }
+
+ ccw_device_get_id(CARD_DDEV(card), &id);
+ request->resp_buf_len = sizeof(*response);
+ request->resp_version = DIAG26C_VERSION2;
+ request->op_code = DIAG26C_GET_MAC;
+ request->devno = id.devno;
+
+ rc = diag26c(request, response, DIAG26C_MAC_SERVICES);
+ if (rc)
+ goto out;
+
+ if ((request->resp_buf_len < sizeof(*response)) ||
+ (response->version != request->resp_version)) {
+ rc = -EIO;
+ QETH_DBF_TEXT(SETUP, 2, "badresp");
+ QETH_DBF_HEX(SETUP, 2, &request->resp_buf_len,
+ sizeof(request->resp_buf_len));
+ } else if (!is_valid_ether_addr(response->mac)) {
+ rc = -EINVAL;
+ QETH_DBF_TEXT(SETUP, 2, "badmac");
+ QETH_DBF_HEX(SETUP, 2, response->mac, ETH_ALEN);
+ } else {
+ ether_addr_copy(card->dev->dev_addr, response->mac);
+ }
+
+out:
+ kfree(response);
+ kfree(request);
+ return rc;
+}
+EXPORT_SYMBOL_GPL(qeth_vm_request_mac);
+
static inline int qeth_get_qdio_q_format(struct qeth_card *card)
{
if (card->info.type == QETH_CARD_TYPE_IQD)
diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c
index 9e7f12aba55e..ad110abfdd47 100644
--- a/drivers/s390/net/qeth_l2_main.c
+++ b/drivers/s390/net/qeth_l2_main.c
@@ -21,6 +21,7 @@
#include <linux/hash.h>
#include <linux/hashtable.h>
#include <linux/string.h>
+#include <asm/setup.h>
#include "qeth_core.h"
#include "qeth_l2.h"

@@ -505,9 +506,19 @@ static int qeth_l2_request_initial_mac(struct qeth_card *card)
int rc = 0;
char vendor_pre[] = {0x02, 0x00, 0x00};

- QETH_DBF_TEXT(SETUP, 2, "doL2init");
+ QETH_DBF_TEXT(SETUP, 2, "l2reqmac");
QETH_DBF_TEXT_(SETUP, 2, "doL2%s", CARD_BUS_ID(card));

+ if (MACHINE_IS_VM) {
+ rc = qeth_vm_request_mac(card);
+ if (!rc)
+ goto out;
+ QETH_DBF_MESSAGE(2, "z/VM MAC Service failed on device %s: x%x\n",
+ CARD_BUS_ID(card), rc);
+ QETH_DBF_TEXT_(SETUP, 2, "err%04x", rc);
+ /* fall back to alternative mechanism: */
+ }
+
if (qeth_is_supported(card, IPA_SETADAPTERPARMS)) {
rc = qeth_query_setadapterparms(card);
if (rc) {
@@ -528,11 +539,12 @@ static int qeth_l2_request_initial_mac(struct qeth_card *card)
QETH_DBF_TEXT_(SETUP, 2, "1err%04x", rc);
return rc;
}
- QETH_DBF_HEX(SETUP, 2, card->dev->dev_addr, OSA_ADDR_LEN);
} else {
eth_random_addr(card->dev->dev_addr);
memcpy(card->dev->dev_addr, vendor_pre, 3);
}
+out:
+ QETH_DBF_HEX(SETUP, 2, card->dev->dev_addr, card->dev->addr_len);
return 0;
}

--
2.11.2