diff --git a/stand/lua/config.lua b/stand/lua/config.lua
--- a/stand/lua/config.lua
+++ b/stand/lua/config.lua
@@ -513,6 +513,22 @@
 	end
 end
 
+-- Auto-load modules required for explicit vfs paths
+-- this allows bhyveload to pass just the env var in
+-- and required modules can be autoloaded, allowing
+-- bhyve to boot from a default FreeBSD install.
+local function enableOptionalRootFSModules()
+	local mountfrom = loader.getenv("vfs.root.mountfrom")
+	if mountfrom == nil then
+		return
+	end
+
+	-- Check for p9fs root and enable virtio_p9fs module
+	if mountfrom:match('^p9fs:') then
+		config.enableModule("virtio_p9fs")
+	end
+end
+
 -- Module exports
 config.verbose = false
 
@@ -858,6 +874,7 @@
 	hook.runAll("kernel.loaded")
 
 	print(MSG_MODLOADING)
+	enableOptionalRootFSModules()
 	status = loadModule(modules, not config.verbose)
 	hook.runAll("modules.loaded")
 	return status