Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 48 insertions, 0 deletions

diff --git a/pc-bios/s390-ccw/helper.h b/pc-bios/s390-ccw/helper.h
new file mode 100644
index 000000000..3d0731c4c
--- /dev/null
+++ b/pc-bios/s390-ccw/helper.h
@@ -0,0 +1,48 @@
+/*
+ * Helper Functions
+ *
+ * Copyright (c) 2019 IBM Corp.
+ *
+ * Author(s): Jason J. Herne <jjherne@us.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or (at
+ * your option) any later version. See the COPYING file in the top-level
+ * directory.
+ */
+
+#ifndef S390_CCW_HELPER_H
+#define S390_CCW_HELPER_H
+
+#include "s390-ccw.h"
+#include "s390-time.h"
+
+/* Avoids compiler warnings when casting a pointer to a u32 */
+static inline uint32_t ptr2u32(void *ptr)
+{
+    IPL_assert((uint64_t)ptr <= 0xffffffffull, "ptr2u32: ptr too large");
+    return (uint32_t)(uint64_t)ptr;
+}
+
+/* Avoids compiler warnings when casting a u32 to a pointer */
+static inline void *u32toptr(uint32_t n)
+{
+    return (void *)(uint64_t)n;
+}
+
+static inline void yield(void)
+{
+    asm volatile ("diag %%r0,%%r0,0x44"
+                  : :
+                  : "memory", "cc");
+}
+
+static inline void sleep(unsigned int seconds)
+{
+    ulong target = get_time_seconds() + seconds;
+
+    while (get_time_seconds() < target) {
+        yield();
+    }
+}
+
+#endif