[...]
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -46,20 +46,33 @@
static struct vhost_log *vhost_log;
static struct vhost_log *vhost_log_shm;
+/* Memslots used by backends that support private memslots (without an fd). */
static unsigned int used_memslots;
+
+/* Memslots used by backends that only support shared memslots (with an fd). */
+static unsigned int used_shared_memslots;
It's just that these vars are updated multiple times when >1 vhost is
there, accessing these fields are still a bit confusing - I think it's
implicitly protected by BQL so looks always safe.
Yes, like the existing variable.
Since we already have the shared/private handling, maybe for the long term
it'll be nicer to just keep such info per-device e.g. in vhost_dev so we
can also drop vhost_backend_no_private_memslots(). Anyway the code is
internal so can be done on top even if worthwhile.
Might be possible, but I remember there was a catch to it when
hotplugging a device.
+
static QLIST_HEAD(, vhost_dev) vhost_devices =
QLIST_HEAD_INITIALIZER(vhost_devices);
bool vhost_has_free_slot(void)
{
- unsigned int slots_limit = ~0U;
+ unsigned int free = UINT_MAX;
struct vhost_dev *hdev;
QLIST_FOREACH(hdev, &vhost_devices, entry) {
unsigned int r = hdev->vhost_ops->vhost_backend_memslots_limit(hdev);
- slots_limit = MIN(slots_limit, r);
+ unsigned int cur_free;
+
+ if (hdev->vhost_ops->vhost_backend_no_private_memslots &&
+ hdev->vhost_ops->vhost_backend_no_private_memslots(hdev)) {
+ cur_free = r - used_shared_memslots;
+ } else {
+ cur_free = r - used_memslots;
+ }
+ free = MIN(free, cur_free);
}
- return slots_limit > used_memslots;
+ return free > 1;
Should here be "free > 0" instead?
Trivial but maybe still matter when some device used exactly the size of
all memslots of a device..
Very good catch, thanks Peter!
--
Thanks,
David / dhildenb
