在 2022/1/22 上午4:27, Eugenio Pérez 写道:
SVQ is able to log the dirty bits by itself, so let's use it to not
block migration.
Also, ignore set and clear of VHOST_F_LOG_ALL on set_features if SVQ is
enabled. Even if the device supports it, the reports would be nonsense
because SVQ memory is in the qemu region.
The log region is still allocated. Future changes might skip that, but
this series is already long enough.
Signed-off-by: Eugenio Pérez <eperezma@xxxxxxxxxx>
---
hw/virtio/vhost-vdpa.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index fb0a338baa..75090d65e8 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -1022,6 +1022,9 @@ static int vhost_vdpa_get_features(struct vhost_dev *dev, uint64_t *features)
if (ret == 0 && v->shadow_vqs_enabled) {
/* Filter only features that SVQ can offer to guest */
vhost_svq_valid_guest_features(features);
+
+ /* Add SVQ logging capabilities */
+ *features |= BIT_ULL(VHOST_F_LOG_ALL);
}
return ret;
@@ -1039,8 +1042,25 @@ static int vhost_vdpa_set_features(struct vhost_dev *dev,
if (v->shadow_vqs_enabled) {
uint64_t dev_features, svq_features, acked_features;
+ uint8_t status = 0;
bool ok;
+ ret = vhost_vdpa_call(dev, VHOST_VDPA_GET_STATUS, &status);
+ if (unlikely(ret)) {
+ return ret;
+ }
+
+ if (status & VIRTIO_CONFIG_S_DRIVER_OK) {
+ /*
+ * vhost is trying to enable or disable _F_LOG, and the device
+ * would report wrong dirty pages. SVQ handles it.
+ */
I fail to understand this comment, I'd think there's no way to disable
dirty page tracking for SVQ.
Thanks
+ return 0;
+ }
+
+ /* We must not ack _F_LOG if SVQ is enabled */
+ features &= ~BIT_ULL(VHOST_F_LOG_ALL);
+
ret = vhost_vdpa_get_dev_features(dev, &dev_features);
if (ret != 0) {
error_report("Can't get vdpa device features, got (%d)", ret);
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