If the driver uses any of the extended features (i.e. 64 or above),
store the extended features range (64-127 bits).
At load time, let legacy features initialize the full features range
and pass it to the set helper; sub-states loading will have filled-up
the extended part as needed.
This is one of the few spots that need explicitly to know and set
in stone the extended features array size; add a build bug to prevent
breaking the migration should such size change again in the future:
more serialization plumbing will be needed.
Signed-off-by: Paolo Abeni <pab...@redhat.com>
---
v2 -> v3:
- 128bit_features state load/stores only the high bits
- consolidate the load implementation to use a single set
helper for 128/64/32 bits features
- _array -> _ex
v1 -> v2:
- uint128_t -> u64[2]
---
hw/virtio/virtio.c | 88 ++++++++++++++++++++++++++++++----------------
1 file changed, 57 insertions(+), 31 deletions(-)
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 2ab1d20769..2817d3a893 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -2954,6 +2954,24 @@ static const VMStateDescription vmstate_virtio_disabled
= {
}
};
+static bool virtio_128bit_features_needed(void *opaque)
+{
+ VirtIODevice *vdev = opaque;
+
+ return virtio_features_use_extended(vdev->host_features_ex);
+}
+
+static const VMStateDescription vmstate_virtio_128bit_features = {
+ .name = "virtio/128bit_features",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .needed = &virtio_128bit_features_needed,
+ .fields = (const VMStateField[]) {
+ VMSTATE_UINT64(guest_features_ex[1], VirtIODevice),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
static const VMStateDescription vmstate_virtio = {
.name = "virtio",
.version_id = 1,
@@ -2963,6 +2981,7 @@ static const VMStateDescription vmstate_virtio = {
},
.subsections = (const VMStateDescription * const []) {
&vmstate_virtio_device_endian,
+ &vmstate_virtio_128bit_features,
&vmstate_virtio_64bit_features,
&vmstate_virtio_virtqueues,
&vmstate_virtio_ringsize,
@@ -3059,23 +3078,28 @@ const VMStateInfo virtio_vmstate_info = {
.put = virtio_device_put,
};
-static int virtio_set_features_nocheck(VirtIODevice *vdev, uint64_t val)
+static int virtio_set_features_nocheck(VirtIODevice *vdev, const uint64_t *val)
{
VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
- bool bad = (val & ~(vdev->host_features)) != 0;
+ uint64_t tmp[VIRTIO_FEATURES_DWORDS];
+ bool bad;
+
+ bad = virtio_features_andnot(tmp, val, vdev->host_features_ex);
+ virtio_features_and(tmp, val, vdev->host_features_ex);
- val &= vdev->host_features;
if (k->set_features) {
- k->set_features(vdev, val);
+ bad = bad || virtio_features_use_extended(tmp);
+ k->set_features(vdev, tmp[0]);
}
- vdev->guest_features = val;
+
+ virtio_features_copy(vdev->guest_features_ex, tmp);
return bad ? -1 : 0;
}
typedef struct VirtioSetFeaturesNocheckData {
Coroutine *co;
VirtIODevice *vdev;
- uint64_t val;
+ uint64_t val[VIRTIO_FEATURES_DWORDS];
int ret;
} VirtioSetFeaturesNocheckData;
@@ -3088,14 +3112,15 @@ static void virtio_set_features_nocheck_bh(void *opaque)
}
static int coroutine_mixed_fn
-virtio_set_features_nocheck_maybe_co(VirtIODevice *vdev, uint64_t val)
+virtio_set_features_nocheck_maybe_co(VirtIODevice *vdev,
+ const uint64_t *val)
{
if (qemu_in_coroutine()) {
VirtioSetFeaturesNocheckData data = {
.co = qemu_coroutine_self(),
.vdev = vdev,
- .val = val,
};
+ virtio_features_copy(data.val, val);
aio_bh_schedule_oneshot(qemu_get_current_aio_context(),
virtio_set_features_nocheck_bh, &data);
qemu_coroutine_yield();
@@ -3107,6 +3132,7 @@ virtio_set_features_nocheck_maybe_co(VirtIODevice *vdev,
uint64_t val)
int virtio_set_features(VirtIODevice *vdev, uint64_t val)
{
+ uint64_t features[VIRTIO_FEATURES_DWORDS];
int ret;
/*
* The driver must not attempt to set features after feature negotiation
@@ -3122,7 +3148,8 @@ int virtio_set_features(VirtIODevice *vdev, uint64_t val)
__func__, vdev->name);
}
- ret = virtio_set_features_nocheck(vdev, val);
+ virtio_features_from_u64(features, val);
+ ret = virtio_set_features_nocheck(vdev, features);
if (virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
/* VIRTIO_RING_F_EVENT_IDX changes the size of the caches. */
int i;
@@ -3145,6 +3172,7 @@ void virtio_reset(void *opaque)
{
VirtIODevice *vdev = opaque;
VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
+ uint64_t features[VIRTIO_FEATURES_DWORDS];
int i;
virtio_set_status(vdev, 0);
@@ -3171,7 +3199,8 @@ void virtio_reset(void *opaque)
vdev->start_on_kick = false;
vdev->started = false;
vdev->broken = false;
- virtio_set_features_nocheck(vdev, 0);
+ virtio_features_clear(features);
+ virtio_set_features_nocheck(vdev, features);
vdev->queue_sel = 0;
vdev->status = 0;
vdev->disabled = false;
@@ -3254,7 +3283,7 @@ virtio_load(VirtIODevice *vdev, QEMUFile *f, int
version_id)
* Note: devices should always test host features in future - don't create
* new dependencies like this.
*/
- vdev->guest_features = features;
+ virtio_features_from_u64(vdev->guest_features_ex, features);
config_len = qemu_get_be32(f);
@@ -3333,26 +3362,23 @@ virtio_load(VirtIODevice *vdev, QEMUFile *f, int
version_id)
vdev->device_endian = virtio_default_endian();
}
- if (virtio_64bit_features_needed(vdev)) {
- /*
- * Subsection load filled vdev->guest_features. Run them
- * through virtio_set_features to sanity-check them against
- * host_features.
- */
- uint64_t features64 = vdev->guest_features;
- if (virtio_set_features_nocheck_maybe_co(vdev, features64) < 0) {
- error_report("Features 0x%" PRIx64 " unsupported. "
- "Allowed features: 0x%" PRIx64,
- features64, vdev->host_features);
- return -1;
- }
- } else {
- if (virtio_set_features_nocheck_maybe_co(vdev, features) < 0) {
- error_report("Features 0x%x unsupported. "
- "Allowed features: 0x%" PRIx64,
- features, vdev->host_features);
- return -1;
- }
+ /*
+ * Avoid silently breaking migration should the feature space increase
+ * even more in the (far away) future
+ */
+ QEMU_BUILD_BUG_ON(VIRTIO_FEATURES_DWORDS != 2);
+
+ /*
+ * guest_features_ex is fully initialized with u32 features and upper
+ * bits have been filled as needed by the later load.
+ */
+ if (virtio_set_features_nocheck_maybe_co(vdev,
+ vdev->guest_features_ex) < 0) {
+ error_report("Features 0x" VIRTIO_FEATURES_FMT " unsupported. "
+ "Allowed features: 0x" VIRTIO_FEATURES_FMT,
+ VIRTIO_FEATURES_PR(vdev->guest_features_ex),
+ VIRTIO_FEATURES_PR(vdev->host_features_ex));
+ return -1;
}
if (!virtio_device_started(vdev, vdev->status) &&
--
2.50.0
