From: Thomas Huth <thuth@xxxxxxxxxxxxxxxxxx>
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.
Signed-off-by: Thomas Huth <thuth@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Cornelia Huck <cornelia.huck@xxxxxxxxxx>
---
hw/s390x/virtio-ccw.c | 52 +++++++++++++++++++++++++++++++++++++++++++++++++
hw/s390x/virtio-ccw.h | 5 +++++
2 files changed, 57 insertions(+)
diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
index e434718..5311d9f 100644
--- a/hw/s390x/virtio-ccw.c
+++ b/hw/s390x/virtio-ccw.c
@@ -20,9 +20,11 @@
#include "hw/virtio/virtio-net.h"
#include "hw/sysbus.h"
#include "qemu/bitops.h"
+#include "hw/virtio/virtio-access.h"
#include "hw/virtio/virtio-bus.h"
#include "hw/s390x/adapter.h"
#include "hw/s390x/s390_flic.h"
+#include "linux/virtio_config.h"
#include "ioinst.h"
#include "css.h"
@@ -260,6 +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)
@@ -299,6 +307,7 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
{
int ret;
VqInfoBlock info;
+ VirtioRevInfo revinfo;
uint8_t status;
VirtioFeatDesc features;
void *config;
@@ -375,6 +384,13 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
features.features = (uint32_t)dev->host_features;
} else if (features.index == 1) {
features.features = (uint32_t)(dev->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;
@@ -406,6 +422,13 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
(vdev->guest_features & 0xffffffff00000000) |
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 & 0x00000000ffffffff) |
((uint64_t)features.features << 32));
@@ -608,6 +631,25 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
}
}
break;
+ case CCW_CMD_SET_VIRTIO_REV:
+ len = sizeof(revinfo);
+ if (ccw.count < len || (check_len && ccw.count > len)) {
+ ret = -EINVAL;
+ break;
+ }
+ if (!ccw.cda) {
+ ret = -EFAULT;
+ break;
+ }
+ cpu_physical_memory_read(ccw.cda, &revinfo, len);
+ if (dev->revision >= 0 ||
+ revinfo.revision > VIRTIO_CCW_REV_MAX) {
+ ret = -ENOSYS;
+ break;
+ }
+ ret = 0;
+ dev->revision = revinfo.revision;
+ break;
default:
ret = -ENOSYS;
break;
@@ -615,6 +657,13 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
return ret;
}
+static void virtio_sch_disable_cb(SubchDev *sch)
+{
+ VirtioCcwDevice *dev = sch->driver_data;
+
+ dev->revision = -1;
+}
+
static int virtio_ccw_device_init(VirtioCcwDevice *dev, VirtIODevice *vdev)
{
unsigned int cssid = 0;
@@ -740,6 +789,7 @@ static int virtio_ccw_device_init(VirtioCcwDevice *dev, VirtIODevice *vdev)
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));
@@ -747,6 +797,8 @@ static int virtio_ccw_device_init(VirtioCcwDevice *dev, VirtIODevice *vdev)
sch->id.cu_type = VIRTIO_CCW_CU_TYPE;
sch->id.cu_model = vdev->device_id;
+ dev->revision = -1;
+
/* Set default feature bits that are offered by the host. */
dev->host_features = 0;
virtio_add_feature(&dev->host_features, VIRTIO_F_NOTIFY_ON_EMPTY);
diff --git a/hw/s390x/virtio-ccw.h b/hw/s390x/virtio-ccw.h
index 9087f7a..fe5c782 100644
--- a/hw/s390x/virtio-ccw.h
+++ b/hw/s390x/virtio-ccw.h
@@ -40,6 +40,7 @@
#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) \
@@ -68,6 +69,9 @@ typedef struct VirtIOCCWDeviceClass {
int (*exit)(VirtioCcwDevice *dev);
} VirtIOCCWDeviceClass;
+/* The maximum virtio revision we support. */
+#define VIRTIO_CCW_REV_MAX 0
+
/* Performance improves when virtqueue kick processing is decoupled from the
* vcpu thread using ioeventfd for some devices. */
#define VIRTIO_CCW_FLAG_USE_IOEVENTFD_BIT 1
@@ -86,6 +90,7 @@ struct VirtioCcwDevice {
SubchDev *sch;
char *bus_id;
uint64_t host_features;
+ int revision;
VirtioBusState bus;
bool ioeventfd_started;
bool ioeventfd_disabled;
--
1.7.9.5
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