AppleHV enablement pass #2

* Use vfkit command line assembly
* Inject ignition file into guest using http over vsock
* Ready notification through use of vsock

[NO NEW TESTS NEEDED]

Signed-off-by: Brent Baude <bbaude@redhat.com>

vendor/github.com/twitchyliquid64/golang-asm/asm/arch/riscv64.go

@@ -0,0 +1,28 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This file encapsulates some of the odd characteristics of the RISCV64
+// instruction set, to minimize its interaction with the core of the
+// assembler.
+
+package arch
+
+import (
+	"github.com/twitchyliquid64/golang-asm/obj"
+	"github.com/twitchyliquid64/golang-asm/obj/riscv"
+)
+
+// IsRISCV64AMO reports whether the op (as defined by a riscv.A*
+// constant) is one of the AMO instructions that requires special
+// handling.
+func IsRISCV64AMO(op obj.As) bool {
+	switch op {
+	case riscv.ASCW, riscv.ASCD, riscv.AAMOSWAPW, riscv.AAMOSWAPD, riscv.AAMOADDW, riscv.AAMOADDD,
+		riscv.AAMOANDW, riscv.AAMOANDD, riscv.AAMOORW, riscv.AAMOORD, riscv.AAMOXORW, riscv.AAMOXORD,
+		riscv.AAMOMINW, riscv.AAMOMIND, riscv.AAMOMINUW, riscv.AAMOMINUD,
+		riscv.AAMOMAXW, riscv.AAMOMAXD, riscv.AAMOMAXUW, riscv.AAMOMAXUD:
+		return true
+	}
+	return false
+}