Limitations for virtiofs and com.apple.virtio-fs.automount and Virtualization.framework

We're seeing limitations in host -> macOS VM changes syncing. Were using Anka, but we've also tried others. We're actually doing the exact implementation that others (the ones we found that are open source) do.

Here is a breakdown of what's supported:

OperationDirectionSupportedNotes
Create new file/folderHost → Guest✅ YesNew paths appear in the guest
Create new file/folderGuest → Host✅ YesNew paths appear on the host
Read existing contentsHost → Guest✅ YesContents present at mount time are visible
Modify file in placeGuest → Host✅ YesGuest edits are written through to the host
Modify file in placeHost → Guest❌ NoGuest keeps stale contents for already-accessed files (macOS virtiofs caching)
Delete file/folderGuest → Host✅ YesRemoval is reflected on the host
Delete file/folderHost → Guest❌ NoGuest still sees the path after the host deletes it (cached)
Replace via temp + rename() (atomic)Host → Guest✅ YesNew inode/dentry; recommended way to update files from the host

We're requesting a way to disable caching and/or allow the unsupported actions in the table to be supported.

https://feedbackassistant.apple.com/feedback/22905515

Limitations for virtiofs and com.apple.virtio-fs.automount and Virtualization.framework
 
 
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