在 2022/1/22 上午4:27, Eugenio Pérez 写道:
This allows SVQ to negotiate features with the device. For the device,
SVQ is a driver. While this function needs to bypass all non-transport
features, it needs to disable the features that SVQ does not support
when forwarding buffers. This includes packed vq layout, indirect
descriptors or event idx.
Signed-off-by: Eugenio Pérez <eperezma@xxxxxxxxxx>
---
hw/virtio/vhost-shadow-virtqueue.h | 2 ++
hw/virtio/vhost-shadow-virtqueue.c | 44 ++++++++++++++++++++++++++++++
hw/virtio/vhost-vdpa.c | 21 ++++++++++++++
3 files changed, 67 insertions(+)
diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h
index c9ffa11fce..d963867a04 100644
--- a/hw/virtio/vhost-shadow-virtqueue.h
+++ b/hw/virtio/vhost-shadow-virtqueue.h
@@ -15,6 +15,8 @@
typedef struct VhostShadowVirtqueue VhostShadowVirtqueue;
+bool vhost_svq_valid_device_features(uint64_t *features);
+
void vhost_svq_set_svq_kick_fd(VhostShadowVirtqueue *svq, int svq_kick_fd);
void vhost_svq_set_guest_call_notifier(VhostShadowVirtqueue *svq, int call_fd);
const EventNotifier *vhost_svq_get_dev_kick_notifier(
diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
index 9619c8082c..51442b3dbf 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -45,6 +45,50 @@ const EventNotifier *vhost_svq_get_dev_kick_notifier(
return &svq->hdev_kick;
}
+/**
+ * Validate the transport device features that SVQ can use with the device
+ *
+ * @dev_features The device features. If success, the acknowledged features.
+ *
+ * Returns true if SVQ can go with a subset of these, false otherwise.
+ */
+bool vhost_svq_valid_device_features(uint64_t *dev_features)
+{
+ bool r = true;
+
+ for (uint64_t b = VIRTIO_TRANSPORT_F_START; b <= VIRTIO_TRANSPORT_F_END;
+ ++b) {
+ switch (b) {
+ case VIRTIO_F_NOTIFY_ON_EMPTY:
+ case VIRTIO_F_ANY_LAYOUT:
+ continue;
+
+ case VIRTIO_F_ACCESS_PLATFORM:
+ /* SVQ does not know how to translate addresses */
I may miss something but any reason that we need to disable
ACCESS_PLATFORM? I'd expect the vring helper we used for shadow
virtqueue can deal with vIOMMU perfectly.
+ if (*dev_features & BIT_ULL(b)) {
+ clear_bit(b, dev_features);
+ r = false;
+ }
+ break;
+
+ case VIRTIO_F_VERSION_1:
I had the same question here.
Thanks
+ /* SVQ trust that guest vring is little endian */
+ if (!(*dev_features & BIT_ULL(b))) {
+ set_bit(b, dev_features);
+ r = false;
+ }
+ continue;
+
+ default:
+ if (*dev_features & BIT_ULL(b)) {
+ clear_bit(b, dev_features);
+ }
+ }
+ }
+
+ return r;
+}
+
/* Forward guest notifications */
static void vhost_handle_guest_kick(EventNotifier *n)
{
diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index bdb45c8808..9d801cf907 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -855,10 +855,31 @@ static int vhost_vdpa_init_svq(struct vhost_dev *hdev, struct vhost_vdpa *v,
size_t n_svqs = v->shadow_vqs_enabled ? hdev->nvqs : 0;
g_autoptr(GPtrArray) shadow_vqs = g_ptr_array_new_full(n_svqs,
vhost_psvq_free);
+ uint64_t dev_features;
+ uint64_t svq_features;
+ int r;
+ bool ok;
+
if (!v->shadow_vqs_enabled) {
goto out;
}
+ r = vhost_vdpa_get_features(hdev, &dev_features);
+ if (r != 0) {
+ error_setg(errp, "Can't get vdpa device features, got (%d)", r);
+ return r;
+ }
+
+ svq_features = dev_features;
+ ok = vhost_svq_valid_device_features(&svq_features);
+ if (unlikely(!ok)) {
+ error_setg(errp,
+ "SVQ Invalid device feature flags, offer: 0x%"PRIx64", ok: 0x%"PRIx64,
+ hdev->features, svq_features);
+ return -1;
+ }
+
+ shadow_vqs = g_ptr_array_new_full(hdev->nvqs, vhost_psvq_free);
for (unsigned n = 0; n < hdev->nvqs; ++n) {
VhostShadowVirtqueue *svq = vhost_svq_new();
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