diff --git a/sys/contrib/openzfs/include/os/freebsd/spl/sys/simd_aarch64.h b/sys/contrib/openzfs/include/os/freebsd/spl/sys/simd_aarch64.h
--- a/sys/contrib/openzfs/include/os/freebsd/spl/sys/simd_aarch64.h
+++ b/sys/contrib/openzfs/include/os/freebsd/spl/sys/simd_aarch64.h
@@ -44,13 +44,39 @@
 #define	_FREEBSD_SIMD_AARCH64_H
 
 #include <sys/types.h>
+#include <sys/ucontext.h>
 #include <machine/elf.h>
+#include <machine/fpu.h>
 #include <machine/md_var.h>
+#include <machine/pcb.h>
+
+#ifdef _STANDALONE
 
 #define	kfpu_allowed()		0
-#define	kfpu_initialize(tsk)	do {} while (0)
 #define	kfpu_begin()		do {} while (0)
 #define	kfpu_end()		do {} while (0)
+
+#else
+
+/*
+ * XXX kfpu_allowed() should be 1, but this is pending a fix to the BLAKE3
+ * generated assembly to avoid clobbering x18.  Turn it back on after that
+ * lands.
+ */
+#define	kfpu_allowed()		0
+#define	kfpu_begin() do {						\
+	if (__predict_false(!is_fpu_kern_thread(0)))			\
+		fpu_kern_enter(curthread, NULL, FPU_KERN_NOCTX);	\
+} while(0)
+
+#define	kfpu_end() do {							\
+	if (__predict_false(curthread->td_pcb->pcb_fpflags & PCB_FP_NOSAVE))	\
+		fpu_kern_leave(curthread, NULL);			\
+} while(0)
+
+#endif
+
+#define	kfpu_initialize(tsk)	do {} while (0)
 #define	kfpu_init()		(0)
 #define	kfpu_fini()		do {} while (0)