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s390x/virtio-ccw: add virtio set-revision call
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Handle the virtio-ccw revision according to what the guest sets.
When revision 1 is selected, we have a virtio-1 standard device
with byteswapping for the virtio rings.

When a channel gets disabled, we have to revert to the legacy behavior
in case the next user of the device does not negotiate the revision 1
anymore (e.g. the boot firmware uses revision 1, but the operating
system only uses the legacy mode).

Note that revisions > 0 are still disabled.

[CH: assure memory accesses are always BE]
Signed-off-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
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@huth @cohuck
huth authored and cohuck committed Jul 2, 2015
1 parent 62ac4a5 commit c42767f
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Showing 2 changed files with 84 additions and 2 deletions.
78 changes: 76 additions & 2 deletions hw/s390x/virtio-ccw.c
View file
Expand Up @@ -21,6 +21,7 @@
#include "hw/sysbus.h"
#include "qemu/bitops.h"
#include "qemu/error-report.h"
#include "hw/virtio/virtio-access.h"
#include "hw/virtio/virtio-bus.h"
#include "hw/s390x/adapter.h"
#include "hw/s390x/s390_flic.h"
Expand Down Expand Up @@ -261,6 +262,12 @@ typedef struct VirtioThinintInfo {
uint8_t isc;
} QEMU_PACKED VirtioThinintInfo;

typedef struct VirtioRevInfo {
uint16_t revision;
uint16_t length;
uint8_t data[0];
} QEMU_PACKED VirtioRevInfo;

/* Specify where the virtqueues for the subchannel are in guest memory. */
static int virtio_ccw_set_vqs(SubchDev *sch, uint64_t addr, uint32_t align,
uint16_t index, uint16_t num)
Expand Down Expand Up @@ -319,6 +326,7 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
{
int ret;
VqInfoBlock info;
VirtioRevInfo revinfo;
uint8_t status;
VirtioFeatDesc features;
void *config;
Expand Down Expand Up @@ -401,7 +409,16 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
MEMTXATTRS_UNSPECIFIED,
NULL);
if (features.index == 0) {
features.features = vdev->host_features;
features.features = (uint32_t)vdev->host_features;
} else if (features.index == 1) {
features.features = (uint32_t)(vdev->host_features >> 32);
/*
* Don't offer version 1 to the guest if it did not
* negotiate at least revision 1.
*/
if (dev->revision <= 0) {
features.features &= ~(1 << (VIRTIO_F_VERSION_1 - 32));
}
} else {
/* Return zeroes if the guest supports more feature bits. */
features.features = 0;
Expand Down Expand Up @@ -437,7 +454,20 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
MEMTXATTRS_UNSPECIFIED,
NULL);
if (features.index == 0) {
virtio_set_features(vdev, features.features);
virtio_set_features(vdev,
(vdev->guest_features & 0xffffffff00000000ULL) |
features.features);
} else if (features.index == 1) {
/*
* The guest should not set version 1 if it didn't
* negotiate a revision >= 1.
*/
if (dev->revision <= 0) {
features.features &= ~(1 << (VIRTIO_F_VERSION_1 - 32));
}
virtio_set_features(vdev,
(vdev->guest_features & 0x00000000ffffffffULL) |
((uint64_t)features.features << 32));
} else {
/*
* If the guest supports more feature bits, assert that it
Expand Down Expand Up @@ -658,13 +688,54 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
}
}
break;
case CCW_CMD_SET_VIRTIO_REV:
len = sizeof(revinfo);
if (ccw.count < len) {
ret = -EINVAL;
break;
}
if (!ccw.cda) {
ret = -EFAULT;
break;
}
revinfo.revision =
address_space_lduw_be(&address_space_memory, ccw.cda,
MEMTXATTRS_UNSPECIFIED, NULL);
revinfo.length =
address_space_lduw_be(&address_space_memory,
ccw.cda + sizeof(revinfo.revision),
MEMTXATTRS_UNSPECIFIED, NULL);
if (ccw.count < len + revinfo.length ||
(check_len && ccw.count > len + revinfo.length)) {
ret = -EINVAL;
break;
}
/*
* Once we start to support revisions with additional data, we'll
* need to fetch it here. Nothing to do for now, though.
*/
if (dev->revision >= 0 ||
revinfo.revision > virtio_ccw_rev_max(vdev)) {
ret = -ENOSYS;
break;
}
ret = 0;
dev->revision = revinfo.revision;
break;
default:
ret = -ENOSYS;
break;
}
return ret;
}

static void virtio_sch_disable_cb(SubchDev *sch)
{
VirtioCcwDevice *dev = sch->driver_data;

dev->revision = -1;
}

static void virtio_ccw_device_realize(VirtioCcwDevice *dev, Error **errp)
{
unsigned int cssid = 0;
Expand Down Expand Up @@ -784,12 +855,15 @@ static void virtio_ccw_device_realize(VirtioCcwDevice *dev, Error **errp)
css_sch_build_virtual_schib(sch, 0, VIRTIO_CCW_CHPID_TYPE);

sch->ccw_cb = virtio_ccw_cb;
sch->disable_cb = virtio_sch_disable_cb;

/* Build senseid data. */
memset(&sch->id, 0, sizeof(SenseId));
sch->id.reserved = 0xff;
sch->id.cu_type = VIRTIO_CCW_CU_TYPE;

dev->revision = -1;

if (k->realize) {
k->realize(dev, &err);
}
Expand Down
8 changes: 8 additions & 0 deletions hw/s390x/virtio-ccw.h
View file
Expand Up @@ -41,6 +41,7 @@
#define CCW_CMD_SET_CONF_IND 0x53
#define CCW_CMD_READ_VQ_CONF 0x32
#define CCW_CMD_SET_IND_ADAPTER 0x73
#define CCW_CMD_SET_VIRTIO_REV 0x83

#define TYPE_VIRTIO_CCW_DEVICE "virtio-ccw-device"
#define VIRTIO_CCW_DEVICE(obj) \
Expand Down Expand Up @@ -86,6 +87,7 @@ struct VirtioCcwDevice {
DeviceState parent_obj;
SubchDev *sch;
char *bus_id;
int revision;
VirtioBusState bus;
bool ioeventfd_started;
bool ioeventfd_disabled;
Expand All @@ -99,6 +101,12 @@ struct VirtioCcwDevice {
uint64_t ind_bit;
};

/* The maximum virtio revision we support. */
static inline int virtio_ccw_rev_max(VirtIODevice *vdev)
{
return 0;
}

/* virtual css bus type */
typedef struct VirtualCssBus {
BusState parent_obj;
Expand Down

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