[PATCH 5/6] s390x/virtio-ccw: reference-counted indicators

Cornelia Huck
2014-02-25T17:25:19Z

Make code using the same indicators point to a single allocated structure
that is freed when the last user goes away.

This will be used by the irqfd code to unmap addresses after the last user
is gone.

Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
---
hw/s390x/virtio-ccw.c | 80 ++++++++++++++++++++++++++++++++++++++-----------
hw/s390x/virtio-ccw.h | 13 ++++++--
2 files changed, 73 insertions(+), 20 deletions(-)

diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
index 4125100..c218acd 100644
--- a/hw/s390x/virtio-ccw.c
+++ b/hw/s390x/virtio-ccw.c
@@ -27,6 +27,38 @@
#include "virtio-ccw.h"
#include "trace.h"

+static QTAILQ_HEAD(, IndAddr) indicator_addresses =
+ QTAILQ_HEAD_INITIALIZER(indicator_addresses);
+
+static IndAddr *get_indicator(hwaddr ind_addr, int len)
+{
+ IndAddr *indicator;
+
+ QTAILQ_FOREACH(indicator, &indicator_addresses, sibling) {
+ if (indicator->addr == ind_addr) {
+ indicator->refcnt++;
+ return indicator;
+ }
+ }
+ indicator = g_new0(IndAddr, 1);
+ indicator->addr = ind_addr;
+ indicator->len = len;
+ indicator->refcnt = 1;
+ QTAILQ_INSERT_TAIL(&indicator_addresses, indicator, sibling);
+ return indicator;
+}
+
+static void release_indicator(IndAddr *indicator)
+{
+ assert(indicator->refcnt > 0);
+ indicator->refcnt--;
+ if (indicator->refcnt > 0) {
+ return;
+ }
+ QTAILQ_REMOVE(&indicator_addresses, indicator, sibling);
+ g_free(indicator);
+}
+
static void virtio_ccw_bus_new(VirtioBusState *bus, size_t bus_size,
VirtioCcwDevice *dev);

@@ -445,7 +477,7 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
ret = -EFAULT;
} else {
indicators = ldq_phys(&address_space_memory, ccw.cda);
- dev->indicators = indicators;
+ dev->indicators = get_indicator(indicators, sizeof(uint64_t));
sch->curr_status.scsw.count = ccw.count - sizeof(indicators);
ret = 0;
}
@@ -465,7 +497,7 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
ret = -EFAULT;
} else {
indicators = ldq_phys(&address_space_memory, ccw.cda);
- dev->indicators2 = indicators;
+ dev->indicators2 = get_indicator(indicators, sizeof(uint64_t));
sch->curr_status.scsw.count = ccw.count - sizeof(indicators);
ret = 0;
}
@@ -517,8 +549,10 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
ret = -EFAULT;
} else {
len = hw_len;
- dev->summary_indicator = thinint->summary_indicator;
- dev->indicators = thinint->device_indicator;
+ dev->summary_indicator =
+ get_indicator(thinint->summary_indicator, sizeof(uint8_t));
+ dev->indicators = get_indicator(thinint->device_indicator,
+ thinint->ind_bit / 8 + 1);
dev->thinint_isc = thinint->isc;
dev->ind_bit = thinint->ind_bit;
cpu_physical_memory_unmap(thinint, hw_len, 0, hw_len);
@@ -526,8 +560,8 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
dev->thinint_isc, true, false,
&dev->adapter_id);
assert(ret == 0);
- sch->thinint_active = ((dev->indicators != 0) &&
- (dev->summary_indicator != 0));
+ sch->thinint_active = ((dev->indicators != NULL) &&
+ (dev->summary_indicator != NULL));
sch->curr_status.scsw.count = ccw.count - len;
ret = 0;
}
@@ -558,7 +592,7 @@ static int virtio_ccw_device_init(VirtioCcwDevice *dev, VirtIODevice *vdev)
sch->driver_data = dev;
dev->sch = sch;

- dev->indicators = 0;
+ dev->indicators = NULL;

/* Initialize subchannel structure. */
sch->channel_prog = 0x0;
@@ -698,7 +732,10 @@ static int virtio_ccw_exit(VirtioCcwDevice *dev)
css_subch_assign(sch->cssid, sch->ssid, sch->schid, sch->devno, NULL);
g_free(sch);
}
- dev->indicators = 0;
+ if (dev->indicators) {
+ release_indicator(dev->indicators);
+ dev->indicators = NULL;
+ }
return 0;
}

@@ -955,17 +992,17 @@ static void virtio_ccw_notify(DeviceState *d, uint16_t vector)
* ind_bit indicates the start of the indicators in a big
* endian notation.
*/
- virtio_set_ind_atomic(sch, dev->indicators +
+ virtio_set_ind_atomic(sch, dev->indicators->addr +
(dev->ind_bit + vector) / 8,
0x80 >> ((dev->ind_bit + vector) % 8));
- if (!virtio_set_ind_atomic(sch, dev->summary_indicator,
+ if (!virtio_set_ind_atomic(sch, dev->summary_indicator->addr,
0x01)) {
css_adapter_interrupt(dev->thinint_isc);
}
} else {
- indicators = ldq_phys(&address_space_memory, dev->indicators);
+ indicators = ldq_phys(&address_space_memory, dev->indicators->addr);
indicators |= 1ULL << vector;
- stq_phys(&address_space_memory, dev->indicators, indicators);
+ stq_phys(&address_space_memory, dev->indicators->addr, indicators);
css_conditional_io_interrupt(sch);
}
} else {
@@ -973,9 +1010,9 @@ static void virtio_ccw_notify(DeviceState *d, uint16_t vector)
return;
}
vector = 0;
- indicators = ldq_phys(&address_space_memory, dev->indicators2);
+ indicators = ldq_phys(&address_space_memory, dev->indicators2->addr);
indicators |= 1ULL << vector;
- stq_phys(&address_space_memory, dev->indicators2, indicators);
+ stq_phys(&address_space_memory, dev->indicators2->addr, indicators);
css_conditional_io_interrupt(sch);
}
}
@@ -996,9 +1033,18 @@ static void virtio_ccw_reset(DeviceState *d)
virtio_ccw_stop_ioeventfd(dev);
virtio_reset(vdev);
css_reset_sch(dev->sch);
- dev->indicators = 0;
- dev->indicators2 = 0;
- dev->summary_indicator = 0;
+ if (dev->indicators) {
+ release_indicator(dev->indicators);
+ dev->indicators = NULL;
+ }
+ if (dev->indicators2) {
+ release_indicator(dev->indicators2);
+ dev->indicators2 = NULL;
+ }
+ if (dev->summary_indicator) {
+ release_indicator(dev->summary_indicator);
+ dev->summary_indicator = NULL;
+ }
}

static void virtio_ccw_vmstate_change(DeviceState *d, bool running)
diff --git a/hw/s390x/virtio-ccw.h b/hw/s390x/virtio-ccw.h
index 0b70b91..d340bf4 100644
--- a/hw/s390x/virtio-ccw.h
+++ b/hw/s390x/virtio-ccw.h
@@ -75,6 +75,13 @@ typedef struct VirtIOCCWDeviceClass {
#define VIRTIO_CCW_FLAG_USE_IOEVENTFD_BIT 1
#define VIRTIO_CCW_FLAG_USE_IOEVENTFD (1 << VIRTIO_CCW_FLAG_USE_IOEVENTFD_BIT)

+typedef struct IndAddr {
+ hwaddr addr;
+ unsigned long refcnt;
+ int len;
+ QTAILQ_ENTRY(IndAddr) sibling;
+} IndAddr;
+
struct VirtioCcwDevice {
DeviceState parent_obj;
SubchDev *sch;
@@ -87,9 +94,9 @@ struct VirtioCcwDevice {
uint8_t thinint_isc;
uint32_t adapter_id;
/* Guest provided values: */
- hwaddr indicators;
- hwaddr indicators2;
- hwaddr summary_indicator;
+ IndAddr *indicators;
+ IndAddr *indicators2;
+ IndAddr *summary_indicator;
uint64_t ind_bit;
};

--
1.7.9.5