在 2022/2/1 下午7:45, Eugenio Perez Martin 写道:
On Sun, Jan 30, 2022 at 7:50 AM Jason Wang <jasowang@xxxxxxxxxx> wrote:
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.
vhost_log_global_{start,stop} are called at the beginning and end of
migration. To inform the device that it should start logging, they set
or clean VHOST_F_LOG_ALL at vhost_dev_set_log.
Yes, but for SVQ, we can't disable dirty page tracking, isn't it? The
only thing is to ignore or filter out the F_LOG_ALL and pretend to be
enabled and disabled.
While SVQ does not use VHOST_F_LOG_ALL, it exports the feature bit so
vhost does not block migration. Maybe we need to look for another way
to do this?
I'm fine with filtering since it's much more simpler, but I fail to
understand why we need to check DRIVER_OK.
Thanks
Thanks!
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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