#include "hw/s390x/css.h"
#include "trace.h"
#include "hw/s390x/s390_flic.h"
+#include "hw/s390x/s390-virtio-ccw.h"
typedef struct CrwContainer {
CRW crw;
unsigned long devnos_used[BITS_TO_LONGS(MAX_SCHID + 1)];
} SubchSet;
+static const VMStateDescription vmstate_scsw = {
+ .name = "s390_scsw",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .fields = (VMStateField[]) {
+ VMSTATE_UINT16(flags, SCSW),
+ VMSTATE_UINT16(ctrl, SCSW),
+ VMSTATE_UINT32(cpa, SCSW),
+ VMSTATE_UINT8(dstat, SCSW),
+ VMSTATE_UINT8(cstat, SCSW),
+ VMSTATE_UINT16(count, SCSW),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
+static const VMStateDescription vmstate_pmcw = {
+ .name = "s390_pmcw",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .fields = (VMStateField[]) {
+ VMSTATE_UINT32(intparm, PMCW),
+ VMSTATE_UINT16(flags, PMCW),
+ VMSTATE_UINT16(devno, PMCW),
+ VMSTATE_UINT8(lpm, PMCW),
+ VMSTATE_UINT8(pnom, PMCW),
+ VMSTATE_UINT8(lpum, PMCW),
+ VMSTATE_UINT8(pim, PMCW),
+ VMSTATE_UINT16(mbi, PMCW),
+ VMSTATE_UINT8(pom, PMCW),
+ VMSTATE_UINT8(pam, PMCW),
+ VMSTATE_UINT8_ARRAY(chpid, PMCW, 8),
+ VMSTATE_UINT32(chars, PMCW),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
+static const VMStateDescription vmstate_schib = {
+ .name = "s390_schib",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .fields = (VMStateField[]) {
+ VMSTATE_STRUCT(pmcw, SCHIB, 0, vmstate_pmcw, PMCW),
+ VMSTATE_STRUCT(scsw, SCHIB, 0, vmstate_scsw, SCSW),
+ VMSTATE_UINT64(mba, SCHIB),
+ VMSTATE_UINT8_ARRAY(mda, SCHIB, 4),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
+
+static const VMStateDescription vmstate_ccw1 = {
+ .name = "s390_ccw1",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .fields = (VMStateField[]) {
+ VMSTATE_UINT8(cmd_code, CCW1),
+ VMSTATE_UINT8(flags, CCW1),
+ VMSTATE_UINT16(count, CCW1),
+ VMSTATE_UINT32(cda, CCW1),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
+static const VMStateDescription vmstate_ciw = {
+ .name = "s390_ciw",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .fields = (VMStateField[]) {
+ VMSTATE_UINT8(type, CIW),
+ VMSTATE_UINT8(command, CIW),
+ VMSTATE_UINT16(count, CIW),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
+static const VMStateDescription vmstate_sense_id = {
+ .name = "s390_sense_id",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .fields = (VMStateField[]) {
+ VMSTATE_UINT8(reserved, SenseId),
+ VMSTATE_UINT16(cu_type, SenseId),
+ VMSTATE_UINT8(cu_model, SenseId),
+ VMSTATE_UINT16(dev_type, SenseId),
+ VMSTATE_UINT8(dev_model, SenseId),
+ VMSTATE_UINT8(unused, SenseId),
+ VMSTATE_STRUCT_ARRAY(ciw, SenseId, MAX_CIWS, 0, vmstate_ciw, CIW),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
+static int subch_dev_post_load(void *opaque, int version_id);
+static void subch_dev_pre_save(void *opaque);
+
+const char err_hint_devno[] = "Devno mismatch, tried to load wrong section!"
+ " Likely reason: some sequences of plug and unplug can break"
+ " migration for machine versions prior to 2.7 (known design flaw).";
+
+const VMStateDescription vmstate_subch_dev = {
+ .name = "s390_subch_dev",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .post_load = subch_dev_post_load,
+ .pre_save = subch_dev_pre_save,
+ .fields = (VMStateField[]) {
+ VMSTATE_UINT8_EQUAL(cssid, SubchDev, "Bug!"),
+ VMSTATE_UINT8_EQUAL(ssid, SubchDev, "Bug!"),
+ VMSTATE_UINT16(migrated_schid, SubchDev),
+ VMSTATE_UINT16_EQUAL(devno, SubchDev, err_hint_devno),
+ VMSTATE_BOOL(thinint_active, SubchDev),
+ VMSTATE_STRUCT(curr_status, SubchDev, 0, vmstate_schib, SCHIB),
+ VMSTATE_UINT8_ARRAY(sense_data, SubchDev, 32),
+ VMSTATE_UINT64(channel_prog, SubchDev),
+ VMSTATE_STRUCT(last_cmd, SubchDev, 0, vmstate_ccw1, CCW1),
+ VMSTATE_BOOL(last_cmd_valid, SubchDev),
+ VMSTATE_STRUCT(id, SubchDev, 0, vmstate_sense_id, SenseId),
+ VMSTATE_BOOL(ccw_fmt_1, SubchDev),
+ VMSTATE_UINT8(ccw_no_data_cnt, SubchDev),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
+typedef struct IndAddrPtrTmp {
+ IndAddr **parent;
+ uint64_t addr;
+ int32_t len;
+} IndAddrPtrTmp;
+
+static int post_load_ind_addr(void *opaque, int version_id)
+{
+ IndAddrPtrTmp *ptmp = opaque;
+ IndAddr **ind_addr = ptmp->parent;
+
+ if (ptmp->len != 0) {
+ *ind_addr = get_indicator(ptmp->addr, ptmp->len);
+ } else {
+ *ind_addr = NULL;
+ }
+ return 0;
+}
+
+static void pre_save_ind_addr(void *opaque)
+{
+ IndAddrPtrTmp *ptmp = opaque;
+ IndAddr *ind_addr = *(ptmp->parent);
+
+ if (ind_addr != NULL) {
+ ptmp->len = ind_addr->len;
+ ptmp->addr = ind_addr->addr;
+ } else {
+ ptmp->len = 0;
+ ptmp->addr = 0L;
+ }
+}
+
+const VMStateDescription vmstate_ind_addr_tmp = {
+ .name = "s390_ind_addr_tmp",
+ .pre_save = pre_save_ind_addr,
+ .post_load = post_load_ind_addr,
+
+ .fields = (VMStateField[]) {
+ VMSTATE_INT32(len, IndAddrPtrTmp),
+ VMSTATE_UINT64(addr, IndAddrPtrTmp),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
+const VMStateDescription vmstate_ind_addr = {
+ .name = "s390_ind_addr_tmp",
+ .fields = (VMStateField[]) {
+ VMSTATE_WITH_TMP(IndAddr*, IndAddrPtrTmp, vmstate_ind_addr_tmp),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
typedef struct CssImage {
SubchSet *sch_set[MAX_SSID + 1];
ChpInfo chpids[MAX_CHPID + 1];
QTAILQ_HEAD_INITIALIZER(channel_subsys.indicator_addresses),
};
+static void subch_dev_pre_save(void *opaque)
+{
+ SubchDev *s = opaque;
+
+ /* Prepare remote_schid for save */
+ s->migrated_schid = s->schid;
+}
+
+static int subch_dev_post_load(void *opaque, int version_id)
+{
+
+ SubchDev *s = opaque;
+
+ /* Re-assign the subchannel to remote_schid if necessary */
+ if (s->migrated_schid != s->schid) {
+ if (css_find_subch(true, s->cssid, s->ssid, s->schid) == s) {
+ /*
+ * Cleanup the slot before moving to s->migrated_schid provided
+ * it still belongs to us, i.e. it was not changed by previous
+ * invocation of this function.
+ */
+ css_subch_assign(s->cssid, s->ssid, s->schid, s->devno, NULL);
+ }
+ /* It's OK to re-assign without a prior de-assign. */
+ s->schid = s->migrated_schid;
+ css_subch_assign(s->cssid, s->ssid, s->schid, s->devno, s);
+ }
+
+ /*
+ * Hack alert. If we don't migrate the channel subsystem status
+ * we still need to find out if the guest enabled mss/mcss-e.
+ * If the subchannel is enabled, it certainly was able to access it,
+ * so adjust the max_ssid/max_cssid values for relevant ssid/cssid
+ * values. This is not watertight, but better than nothing.
+ */
+ if (s->curr_status.pmcw.flags & PMCW_FLAGS_MASK_ENA) {
+ if (s->ssid) {
+ channel_subsys.max_ssid = MAX_SSID;
+ }
+ if (s->cssid != channel_subsys.default_cssid) {
+ channel_subsys.max_cssid = MAX_CSSID;
+ }
+ }
+ return 0;
+}
+
IndAddr *get_indicator(hwaddr ind_addr, int len)
{
IndAddr *indicator;
return 0;
}
-void subch_device_save(SubchDev *s, QEMUFile *f)
-{
- int i;
-
- qemu_put_byte(f, s->cssid);
- qemu_put_byte(f, s->ssid);
- qemu_put_be16(f, s->schid);
- qemu_put_be16(f, s->devno);
- qemu_put_byte(f, s->thinint_active);
- /* SCHIB */
- /* PMCW */
- qemu_put_be32(f, s->curr_status.pmcw.intparm);
- qemu_put_be16(f, s->curr_status.pmcw.flags);
- qemu_put_be16(f, s->curr_status.pmcw.devno);
- qemu_put_byte(f, s->curr_status.pmcw.lpm);
- qemu_put_byte(f, s->curr_status.pmcw.pnom);
- qemu_put_byte(f, s->curr_status.pmcw.lpum);
- qemu_put_byte(f, s->curr_status.pmcw.pim);
- qemu_put_be16(f, s->curr_status.pmcw.mbi);
- qemu_put_byte(f, s->curr_status.pmcw.pom);
- qemu_put_byte(f, s->curr_status.pmcw.pam);
- qemu_put_buffer(f, s->curr_status.pmcw.chpid, 8);
- qemu_put_be32(f, s->curr_status.pmcw.chars);
- /* SCSW */
- qemu_put_be16(f, s->curr_status.scsw.flags);
- qemu_put_be16(f, s->curr_status.scsw.ctrl);
- qemu_put_be32(f, s->curr_status.scsw.cpa);
- qemu_put_byte(f, s->curr_status.scsw.dstat);
- qemu_put_byte(f, s->curr_status.scsw.cstat);
- qemu_put_be16(f, s->curr_status.scsw.count);
- qemu_put_be64(f, s->curr_status.mba);
- qemu_put_buffer(f, s->curr_status.mda, 4);
- /* end SCHIB */
- qemu_put_buffer(f, s->sense_data, 32);
- qemu_put_be64(f, s->channel_prog);
- /* last cmd */
- qemu_put_byte(f, s->last_cmd.cmd_code);
- qemu_put_byte(f, s->last_cmd.flags);
- qemu_put_be16(f, s->last_cmd.count);
- qemu_put_be32(f, s->last_cmd.cda);
- qemu_put_byte(f, s->last_cmd_valid);
- qemu_put_byte(f, s->id.reserved);
- qemu_put_be16(f, s->id.cu_type);
- qemu_put_byte(f, s->id.cu_model);
- qemu_put_be16(f, s->id.dev_type);
- qemu_put_byte(f, s->id.dev_model);
- qemu_put_byte(f, s->id.unused);
- for (i = 0; i < ARRAY_SIZE(s->id.ciw); i++) {
- qemu_put_byte(f, s->id.ciw[i].type);
- qemu_put_byte(f, s->id.ciw[i].command);
- qemu_put_be16(f, s->id.ciw[i].count);
- }
- qemu_put_byte(f, s->ccw_fmt_1);
- qemu_put_byte(f, s->ccw_no_data_cnt);
-}
-
-int subch_device_load(SubchDev *s, QEMUFile *f)
-{
- SubchDev *old_s;
- Error *err = NULL;
- uint16_t old_schid = s->schid;
- uint16_t old_devno = s->devno;
- int i;
-
- s->cssid = qemu_get_byte(f);
- s->ssid = qemu_get_byte(f);
- s->schid = qemu_get_be16(f);
- s->devno = qemu_get_be16(f);
- if (s->devno != old_devno) {
- /* Only possible if machine < 2.7 (no css_dev_path) */
-
- error_setg(&err, "%x != %x", old_devno, s->devno);
- error_append_hint(&err, "Devno mismatch, tried to load wrong section!"
- " Likely reason: some sequences of plug and unplug"
- " can break migration for machine versions prior to"
- " 2.7 (known design flaw).\n");
- error_report_err(err);
- return -EINVAL;
- }
- /* Re-assign subch. */
- if (old_schid != s->schid) {
- old_s = channel_subsys.css[s->cssid]->sch_set[s->ssid]->sch[old_schid];
- /*
- * (old_s != s) means that some other device has its correct
- * subchannel already assigned (in load).
- */
- if (old_s == s) {
- css_subch_assign(s->cssid, s->ssid, old_schid, s->devno, NULL);
- }
- /* It's OK to re-assign without a prior de-assign. */
- css_subch_assign(s->cssid, s->ssid, s->schid, s->devno, s);
- }
- s->thinint_active = qemu_get_byte(f);
- /* SCHIB */
- /* PMCW */
- s->curr_status.pmcw.intparm = qemu_get_be32(f);
- s->curr_status.pmcw.flags = qemu_get_be16(f);
- s->curr_status.pmcw.devno = qemu_get_be16(f);
- s->curr_status.pmcw.lpm = qemu_get_byte(f);
- s->curr_status.pmcw.pnom = qemu_get_byte(f);
- s->curr_status.pmcw.lpum = qemu_get_byte(f);
- s->curr_status.pmcw.pim = qemu_get_byte(f);
- s->curr_status.pmcw.mbi = qemu_get_be16(f);
- s->curr_status.pmcw.pom = qemu_get_byte(f);
- s->curr_status.pmcw.pam = qemu_get_byte(f);
- qemu_get_buffer(f, s->curr_status.pmcw.chpid, 8);
- s->curr_status.pmcw.chars = qemu_get_be32(f);
- /* SCSW */
- s->curr_status.scsw.flags = qemu_get_be16(f);
- s->curr_status.scsw.ctrl = qemu_get_be16(f);
- s->curr_status.scsw.cpa = qemu_get_be32(f);
- s->curr_status.scsw.dstat = qemu_get_byte(f);
- s->curr_status.scsw.cstat = qemu_get_byte(f);
- s->curr_status.scsw.count = qemu_get_be16(f);
- s->curr_status.mba = qemu_get_be64(f);
- qemu_get_buffer(f, s->curr_status.mda, 4);
- /* end SCHIB */
- qemu_get_buffer(f, s->sense_data, 32);
- s->channel_prog = qemu_get_be64(f);
- /* last cmd */
- s->last_cmd.cmd_code = qemu_get_byte(f);
- s->last_cmd.flags = qemu_get_byte(f);
- s->last_cmd.count = qemu_get_be16(f);
- s->last_cmd.cda = qemu_get_be32(f);
- s->last_cmd_valid = qemu_get_byte(f);
- s->id.reserved = qemu_get_byte(f);
- s->id.cu_type = qemu_get_be16(f);
- s->id.cu_model = qemu_get_byte(f);
- s->id.dev_type = qemu_get_be16(f);
- s->id.dev_model = qemu_get_byte(f);
- s->id.unused = qemu_get_byte(f);
- for (i = 0; i < ARRAY_SIZE(s->id.ciw); i++) {
- s->id.ciw[i].type = qemu_get_byte(f);
- s->id.ciw[i].command = qemu_get_byte(f);
- s->id.ciw[i].count = qemu_get_be16(f);
- }
- s->ccw_fmt_1 = qemu_get_byte(f);
- s->ccw_no_data_cnt = qemu_get_byte(f);
- /*
- * Hack alert. We don't migrate the channel subsystem status (no
- * device!), but we need to find out if the guest enabled mss/mcss-e.
- * If the subchannel is enabled, it certainly was able to access it,
- * so adjust the max_ssid/max_cssid values for relevant ssid/cssid
- * values. This is not watertight, but better than nothing.
- */
- if (s->curr_status.pmcw.flags & PMCW_FLAGS_MASK_ENA) {
- if (s->ssid) {
- channel_subsys.max_ssid = MAX_SSID;
- }
- if (s->cssid != channel_subsys.default_cssid) {
- channel_subsys.max_cssid = MAX_CSSID;
- }
- }
- return 0;
-}
-
void css_reset_sch(SubchDev *sch)
{
PMCW *p = &sch->curr_status.pmcw;
#include "virtio-ccw.h"
#include "trace.h"
#include "hw/s390x/css-bridge.h"
+#include "hw/s390x/s390-virtio-ccw.h"
#define NR_CLASSIC_INDICATOR_BITS 64
+static int virtio_ccw_dev_post_load(void *opaque, int version_id)
+{
+ VirtioCcwDevice *dev = VIRTIO_CCW_DEVICE(opaque);
+ CcwDevice *ccw_dev = CCW_DEVICE(dev);
+ CCWDeviceClass *ck = CCW_DEVICE_GET_CLASS(ccw_dev);
+
+ ccw_dev->sch->driver_data = dev;
+ if (ccw_dev->sch->thinint_active) {
+ dev->routes.adapter.adapter_id = css_get_adapter_id(
+ CSS_IO_ADAPTER_VIRTIO,
+ dev->thinint_isc);
+ }
+ /* Re-fill subch_id after loading the subchannel states.*/
+ if (ck->refill_ids) {
+ ck->refill_ids(ccw_dev);
+ }
+ return 0;
+}
+
+typedef struct VirtioCcwDeviceTmp {
+ VirtioCcwDevice *parent;
+ uint16_t config_vector;
+} VirtioCcwDeviceTmp;
+
+static void virtio_ccw_dev_tmp_pre_save(void *opaque)
+{
+ VirtioCcwDeviceTmp *tmp = opaque;
+ VirtioCcwDevice *dev = tmp->parent;
+ VirtIODevice *vdev = virtio_bus_get_device(&dev->bus);
+
+ tmp->config_vector = vdev->config_vector;
+}
+
+static int virtio_ccw_dev_tmp_post_load(void *opaque, int version_id)
+{
+ VirtioCcwDeviceTmp *tmp = opaque;
+ VirtioCcwDevice *dev = tmp->parent;
+ VirtIODevice *vdev = virtio_bus_get_device(&dev->bus);
+
+ vdev->config_vector = tmp->config_vector;
+ return 0;
+}
+
+const VMStateDescription vmstate_virtio_ccw_dev_tmp = {
+ .name = "s390_virtio_ccw_dev_tmp",
+ .pre_save = virtio_ccw_dev_tmp_pre_save,
+ .post_load = virtio_ccw_dev_tmp_post_load,
+ .fields = (VMStateField[]) {
+ VMSTATE_UINT16(config_vector, VirtioCcwDeviceTmp),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
+const VMStateDescription vmstate_virtio_ccw_dev = {
+ .name = "s390_virtio_ccw_dev",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .post_load = virtio_ccw_dev_post_load,
+ .fields = (VMStateField[]) {
+ VMSTATE_CCW_DEVICE(parent_obj, VirtioCcwDevice),
+ VMSTATE_PTR_TO_IND_ADDR(indicators, VirtioCcwDevice),
+ VMSTATE_PTR_TO_IND_ADDR(indicators2, VirtioCcwDevice),
+ VMSTATE_PTR_TO_IND_ADDR(summary_indicator, VirtioCcwDevice),
+ /*
+ * Ugly hack because VirtIODevice does not migrate itself.
+ * This also makes legacy via vmstate_save_state possible.
+ */
+ VMSTATE_WITH_TMP(VirtioCcwDevice, VirtioCcwDeviceTmp,
+ vmstate_virtio_ccw_dev_tmp),
+ VMSTATE_STRUCT(routes, VirtioCcwDevice, 1, vmstate_adapter_routes,
+ AdapterRoutes),
+ VMSTATE_UINT8(thinint_isc, VirtioCcwDevice),
+ VMSTATE_INT32(revision, VirtioCcwDevice),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
static void virtio_ccw_bus_new(VirtioBusState *bus, size_t bus_size,
VirtioCcwDevice *dev);
static void virtio_ccw_save_config(DeviceState *d, QEMUFile *f)
{
VirtioCcwDevice *dev = VIRTIO_CCW_DEVICE(d);
- CcwDevice *ccw_dev = CCW_DEVICE(d);
- SubchDev *s = ccw_dev->sch;
- VirtIODevice *vdev = virtio_ccw_get_vdev(s);
-
- subch_device_save(s, f);
- if (dev->indicators != NULL) {
- qemu_put_be32(f, dev->indicators->len);
- qemu_put_be64(f, dev->indicators->addr);
- } else {
- qemu_put_be32(f, 0);
- qemu_put_be64(f, 0UL);
- }
- if (dev->indicators2 != NULL) {
- qemu_put_be32(f, dev->indicators2->len);
- qemu_put_be64(f, dev->indicators2->addr);
- } else {
- qemu_put_be32(f, 0);
- qemu_put_be64(f, 0UL);
- }
- if (dev->summary_indicator != NULL) {
- qemu_put_be32(f, dev->summary_indicator->len);
- qemu_put_be64(f, dev->summary_indicator->addr);
- } else {
- qemu_put_be32(f, 0);
- qemu_put_be64(f, 0UL);
- }
- qemu_put_be16(f, vdev->config_vector);
- qemu_put_be64(f, dev->routes.adapter.ind_offset);
- qemu_put_byte(f, dev->thinint_isc);
- qemu_put_be32(f, dev->revision);
+ vmstate_save_state(f, &vmstate_virtio_ccw_dev, dev, NULL);
}
static int virtio_ccw_load_config(DeviceState *d, QEMUFile *f)
{
VirtioCcwDevice *dev = VIRTIO_CCW_DEVICE(d);
- CcwDevice *ccw_dev = CCW_DEVICE(d);
- CCWDeviceClass *ck = CCW_DEVICE_GET_CLASS(ccw_dev);
- SubchDev *s = ccw_dev->sch;
- VirtIODevice *vdev = virtio_ccw_get_vdev(s);
- int len;
- int ret;
-
- s->driver_data = dev;
- ret = subch_device_load(s, f);
- if (ret) {
- return ret;
- }
- /* Re-fill subch_id after loading the subchannel states.*/
- if (ck->refill_ids) {
- ck->refill_ids(ccw_dev);
- }
- len = qemu_get_be32(f);
- if (len != 0) {
- dev->indicators = get_indicator(qemu_get_be64(f), len);
- } else {
- qemu_get_be64(f);
- dev->indicators = NULL;
- }
- len = qemu_get_be32(f);
- if (len != 0) {
- dev->indicators2 = get_indicator(qemu_get_be64(f), len);
- } else {
- qemu_get_be64(f);
- dev->indicators2 = NULL;
- }
- len = qemu_get_be32(f);
- if (len != 0) {
- dev->summary_indicator = get_indicator(qemu_get_be64(f), len);
- } else {
- qemu_get_be64(f);
- dev->summary_indicator = NULL;
- }
- qemu_get_be16s(f, &vdev->config_vector);
- dev->routes.adapter.ind_offset = qemu_get_be64(f);
- dev->thinint_isc = qemu_get_byte(f);
- dev->revision = qemu_get_be32(f);
- if (s->thinint_active) {
- dev->routes.adapter.adapter_id = css_get_adapter_id(
- CSS_IO_ADAPTER_VIRTIO,
- dev->thinint_isc);
- }
-
- return 0;
+ return vmstate_load_state(f, &vmstate_virtio_ccw_dev, dev, 1);
}
static void virtio_ccw_pre_plugged(DeviceState *d, Error **errp)
projects / mirror_qemu.git / commitdiff