include: import Xen public headers to hw/xen/interface

There's already a partial set here; update them and pull in a more
complete set.

To start with, define __XEN_TOOLS__ in hw/xen/xen.h to ensure that any
internal definitions needed by Xen toolstack libraries are present
regardless of the order in which the headers are included. A reckoning
will come later, once we make the PV backends work in emulation and
untangle the headers for Xen-native vs. generic parts.

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
[dwmw2: Update to Xen public headers from 4.16.2 release, add some in io/,
        define __XEN_TOOLS__ in hw/xen/xen.h, move to hw/xen/interface/]
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>

1 files changed, 60 insertions, 39 deletions

diff --git a/include/hw/xen/interface/io/ring.h b/include/hw/xen/interface/io/ring.h
index 115705f3f4..c486c457e0 100644
--- a/include/hw/xen/interface/io/ring.h
+++ b/include/hw/xen/interface/io/ring.h
@@ -1,6 +1,6 @@
 /******************************************************************************
  * ring.h
- * 
+ *
  * Shared producer-consumer ring macros.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
@@ -33,13 +33,6 @@
  * - standard integers types (uint8_t, uint16_t, etc)
  * They are provided by stdint.h of the standard headers.
  *
- * Before using the different macros, you need to provide the following
- * macros:
- * - xen_mb()  a memory barrier
- * - xen_rmb() a read memory barrier
- * - xen_wmb() a write memory barrier
- * Example of those can be found in xenctrl.h.
- *
  * In addition, if you intend to use the FLEX macros, you also need to
  * provide the following, before invoking the FLEX macros:
  * - size_t
@@ -49,6 +42,14 @@
  * and grant_table.h from the Xen public headers.
  */
 
+#include "../xen-compat.h"
+
+#if __XEN_INTERFACE_VERSION__ < 0x00030208
+#define xen_mb()  mb()
+#define xen_rmb() rmb()
+#define xen_wmb() wmb()
+#endif
+
 typedef unsigned int RING_IDX;
 
 /* Round a 32-bit unsigned constant down to the nearest power of two. */
@@ -61,12 +62,12 @@ typedef unsigned int RING_IDX;
 /*
  * Calculate size of a shared ring, given the total available space for the
  * ring and indexes (_sz), and the name tag of the request/response structure.
- * A ring contains as many entries as will fit, rounded down to the nearest 
+ * A ring contains as many entries as will fit, rounded down to the nearest
  * power of two (so we can mask with (size-1) to loop around).
  */
 #define __CONST_RING_SIZE(_s, _sz) \
     (__RD32(((_sz) - offsetof(struct _s##_sring, ring)) / \
-            sizeof_field(struct _s##_sring, ring[0])))
+	    sizeof(((struct _s##_sring *)0)->ring[0])))
 /*
  * The same for passing in an actual pointer instead of a name tag.
  */
@@ -75,7 +76,7 @@ typedef unsigned int RING_IDX;
 
 /*
  * Macros to make the correct C datatypes for a new kind of ring.
- * 
+ *
  * To make a new ring datatype, you need to have two message structures,
  * let's say request_t, and response_t already defined.
  *
@@ -85,7 +86,7 @@ typedef unsigned int RING_IDX;
  *
  * These expand out to give you a set of types, as you can see below.
  * The most important of these are:
- * 
+ *
  *     mytag_sring_t      - The shared ring.
  *     mytag_front_ring_t - The 'front' half of the ring.
  *     mytag_back_ring_t  - The 'back' half of the ring.
@@ -153,15 +154,15 @@ typedef struct __name##_back_ring __name##_back_ring_t
 
 /*
  * Macros for manipulating rings.
- * 
- * FRONT_RING_whatever works on the "front end" of a ring: here 
+ *
+ * FRONT_RING_whatever works on the "front end" of a ring: here
  * requests are pushed on to the ring and responses taken off it.
- * 
- * BACK_RING_whatever works on the "back end" of a ring: here 
+ *
+ * BACK_RING_whatever works on the "back end" of a ring: here
  * requests are taken off the ring and responses put on.
- * 
- * N.B. these macros do NO INTERLOCKS OR FLOW CONTROL. 
- * This is OK in 1-for-1 request-response situations where the 
+ *
+ * N.B. these macros do NO INTERLOCKS OR FLOW CONTROL.
+ * This is OK in 1-for-1 request-response situations where the
  * requestor (front end) never has more than RING_SIZE()-1
  * outstanding requests.
  */
@@ -174,20 +175,24 @@ typedef struct __name##_back_ring __name##_back_ring_t
     (void)memset((_s)->__pad, 0, sizeof((_s)->__pad));                  \
 } while(0)
 
-#define FRONT_RING_INIT(_r, _s, __size) do {                            \
-    (_r)->req_prod_pvt = 0;                                             \
-    (_r)->rsp_cons = 0;                                                 \
+#define FRONT_RING_ATTACH(_r, _s, _i, __size) do {                      \
+    (_r)->req_prod_pvt = (_i);                                          \
+    (_r)->rsp_cons = (_i);                                              \
     (_r)->nr_ents = __RING_SIZE(_s, __size);                            \
     (_r)->sring = (_s);                                                 \
 } while (0)
 
-#define BACK_RING_INIT(_r, _s, __size) do {                             \
-    (_r)->rsp_prod_pvt = 0;                                             \
-    (_r)->req_cons = 0;                                                 \
+#define FRONT_RING_INIT(_r, _s, __size) FRONT_RING_ATTACH(_r, _s, 0, __size)
+
+#define BACK_RING_ATTACH(_r, _s, _i, __size) do {                       \
+    (_r)->rsp_prod_pvt = (_i);                                          \
+    (_r)->req_cons = (_i);                                              \
     (_r)->nr_ents = __RING_SIZE(_s, __size);                            \
     (_r)->sring = (_s);                                                 \
 } while (0)
 
+#define BACK_RING_INIT(_r, _s, __size) BACK_RING_ATTACH(_r, _s, 0, __size)
+
 /* How big is this ring? */
 #define RING_SIZE(_r)                                                   \
     ((_r)->nr_ents)
@@ -206,33 +211,45 @@ typedef struct __name##_back_ring __name##_back_ring_t
 #define RING_HAS_UNCONSUMED_RESPONSES(_r)                               \
     ((_r)->sring->rsp_prod - (_r)->rsp_cons)
 
+#ifdef __GNUC__
 #define RING_HAS_UNCONSUMED_REQUESTS(_r) ({                             \
     unsigned int req = (_r)->sring->req_prod - (_r)->req_cons;          \
     unsigned int rsp = RING_SIZE(_r) -                                  \
         ((_r)->req_cons - (_r)->rsp_prod_pvt);                          \
     req < rsp ? req : rsp;                                              \
 })
+#else
+/* Same as above, but without the nice GCC ({ ... }) syntax. */
+#define RING_HAS_UNCONSUMED_REQUESTS(_r)                                \
+    ((((_r)->sring->req_prod - (_r)->req_cons) <                        \
+      (RING_SIZE(_r) - ((_r)->req_cons - (_r)->rsp_prod_pvt))) ?        \
+     ((_r)->sring->req_prod - (_r)->req_cons) :                         \
+     (RING_SIZE(_r) - ((_r)->req_cons - (_r)->rsp_prod_pvt)))
+#endif
 
 /* Direct access to individual ring elements, by index. */
 #define RING_GET_REQUEST(_r, _idx)                                      \
     (&((_r)->sring->ring[((_idx) & (RING_SIZE(_r) - 1))].req))
 
+#define RING_GET_RESPONSE(_r, _idx)                                     \
+    (&((_r)->sring->ring[((_idx) & (RING_SIZE(_r) - 1))].rsp))
+
 /*
- * Get a local copy of a request.
+ * Get a local copy of a request/response.
  *
- * Use this in preference to RING_GET_REQUEST() so all processing is
+ * Use this in preference to RING_GET_{REQUEST,RESPONSE}() so all processing is
  * done on a local copy that cannot be modified by the other end.
  *
  * Note that https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145 may cause this
- * to be ineffective where _req is a struct which consists of only bitfields.
+ * to be ineffective where dest is a struct which consists of only bitfields.
  */
-#define RING_COPY_REQUEST(_r, _idx, _req) do {				\
-        /* Use volatile to force the copy into _req. */			\
-        *(_req) = *(volatile typeof(_req))RING_GET_REQUEST(_r, _idx);	\
+#define RING_COPY_(type, r, idx, dest) do {				\
+	/* Use volatile to force the copy into dest. */			\
+	*(dest) = *(volatile __typeof__(dest))RING_GET_##type(r, idx);	\
 } while (0)
 
-#define RING_GET_RESPONSE(_r, _idx)                                     \
-    (&((_r)->sring->ring[((_idx) & (RING_SIZE(_r) - 1))].rsp))
+#define RING_COPY_REQUEST(r, idx, req)  RING_COPY_(REQUEST, r, idx, req)
+#define RING_COPY_RESPONSE(r, idx, rsp) RING_COPY_(RESPONSE, r, idx, rsp)
 
 /* Loop termination condition: Would the specified index overflow the ring? */
 #define RING_REQUEST_CONS_OVERFLOW(_r, _cons)                           \
@@ -242,6 +259,10 @@ typedef struct __name##_back_ring __name##_back_ring_t
 #define RING_REQUEST_PROD_OVERFLOW(_r, _prod)                           \
     (((_prod) - (_r)->rsp_prod_pvt) > RING_SIZE(_r))
 
+/* Ill-behaved backend determination: Can there be this many responses? */
+#define RING_RESPONSE_PROD_OVERFLOW(_r, _prod)                          \
+    (((_prod) - (_r)->rsp_cons) > RING_SIZE(_r))
+
 #define RING_PUSH_REQUESTS(_r) do {                                     \
     xen_wmb(); /* back sees requests /before/ updated producer index */ \
     (_r)->sring->req_prod = (_r)->req_prod_pvt;                         \
@@ -254,26 +275,26 @@ typedef struct __name##_back_ring __name##_back_ring_t
 
 /*
  * Notification hold-off (req_event and rsp_event):
- * 
+ *
  * When queueing requests or responses on a shared ring, it may not always be
  * necessary to notify the remote end. For example, if requests are in flight
  * in a backend, the front may be able to queue further requests without
  * notifying the back (if the back checks for new requests when it queues
  * responses).
- * 
+ *
  * When enqueuing requests or responses:
- * 
+ *
  *  Use RING_PUSH_{REQUESTS,RESPONSES}_AND_CHECK_NOTIFY(). The second argument
  *  is a boolean return value. True indicates that the receiver requires an
  *  asynchronous notification.
- * 
+ *
  * After dequeuing requests or responses (before sleeping the connection):
- * 
+ *
  *  Use RING_FINAL_CHECK_FOR_REQUESTS() or RING_FINAL_CHECK_FOR_RESPONSES().
  *  The second argument is a boolean return value. True indicates that there
  *  are pending messages on the ring (i.e., the connection should not be put
  *  to sleep).
- * 
+ *
  *  These macros will set the req_event/rsp_event field to trigger a
  *  notification on the very next message that is enqueued. If you want to
  *  create batches of work (i.e., only receive a notification after several