[Qemu-devel] [PATCH v3 1/2] Type-safe ioport callbacks

[Avi Kivity <avi@redhat.com>]

The current ioport callbacks are not type-safe, in that they accept an "opaque"
pointer as an argument whose type must match the argument to the registration
function; this is not checked by the compiler.

This patch adds an alternative that is type-safe.  Instead of an opaque
argument, both registation and the callback use a new IOPort type.  The
callback then uses container_of() to access its main structures.

Currently the old and new methods exist side by side; once the old way is gone,
we can also save a bunch of memory since the new method requires one pointer
per ioport instead of 6.

Acked-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
 ioport.c  |   64 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 ioport.h  |    2 +
 iorange.h |   30 ++++++++++++++++++++++++++++
 3 files changed, 96 insertions(+), 0 deletions(-)
 create mode 100644 iorange.h

diff --git a/ioport.c b/ioport.c
index ec3dc65..aa4188a 100644
--- a/ioport.c
+++ b/ioport.c
@@ -174,6 +174,70 @@ int register_ioport_write(pio_addr_t start, int length, int size,
     return 0;
 }
 
+static uint32_t ioport_readb_thunk(void *opaque, uint32_t addr)
+{
+    IORange *ioport = opaque;
+    uint64_t data;
+
+    ioport->ops->read(ioport, addr - ioport->base, 1, &data);
+    return data;
+}
+
+static uint32_t ioport_readw_thunk(void *opaque, uint32_t addr)
+{
+    IORange *ioport = opaque;
+    uint64_t data;
+
+    ioport->ops->read(ioport, addr - ioport->base, 2, &data);
+    return data;
+}
+
+static uint32_t ioport_readl_thunk(void *opaque, uint32_t addr)
+{
+    IORange *ioport = opaque;
+    uint64_t data;
+
+    ioport->ops->read(ioport, addr - ioport->base, 4, &data);
+    return data;
+}
+
+static void ioport_writeb_thunk(void *opaque, uint32_t addr, uint32_t data)
+{
+    IORange *ioport = opaque;
+
+    ioport->ops->write(ioport, addr - ioport->base, 1, data);
+}
+
+static void ioport_writew_thunk(void *opaque, uint32_t addr, uint32_t data)
+{
+    IORange *ioport = opaque;
+
+    ioport->ops->write(ioport, addr - ioport->base, 2, data);
+}
+
+static void ioport_writel_thunk(void *opaque, uint32_t addr, uint32_t data)
+{
+    IORange *ioport = opaque;
+
+    ioport->ops->write(ioport, addr - ioport->base, 4, data);
+}
+
+void ioport_register(IORange *ioport)
+{
+    register_ioport_read(ioport->base, ioport->len, 1,
+                         ioport_readb_thunk, ioport);
+    register_ioport_read(ioport->base, ioport->len, 2,
+                         ioport_readw_thunk, ioport);
+    register_ioport_read(ioport->base, ioport->len, 4,
+                         ioport_readl_thunk, ioport);
+    register_ioport_write(ioport->base, ioport->len, 1,
+                          ioport_writeb_thunk, ioport);
+    register_ioport_write(ioport->base, ioport->len, 2,
+                          ioport_writew_thunk, ioport);
+    register_ioport_write(ioport->base, ioport->len, 4,
+                          ioport_writel_thunk, ioport);
+}
+
 void isa_unassign_ioport(pio_addr_t start, int length)
 {
     int i;
diff --git a/ioport.h b/ioport.h
index 3d3c8a3..5ae62a3 100644
--- a/ioport.h
+++ b/ioport.h
@@ -25,6 +25,7 @@
 #define IOPORT_H
 
 #include "qemu-common.h"
+#include "iorange.h"
 
 typedef uint32_t pio_addr_t;
 #define FMT_pioaddr     PRIx32
@@ -36,6 +37,7 @@ typedef uint32_t pio_addr_t;
 typedef void (IOPortWriteFunc)(void *opaque, uint32_t address, uint32_t data);
 typedef uint32_t (IOPortReadFunc)(void *opaque, uint32_t address);
 
+void ioport_register(IORange *iorange);
 int register_ioport_read(pio_addr_t start, int length, int size,
                          IOPortReadFunc *func, void *opaque);
 int register_ioport_write(pio_addr_t start, int length, int size,
diff --git a/iorange.h b/iorange.h
new file mode 100644
index 0000000..9783168
--- /dev/null
+++ b/iorange.h
@@ -0,0 +1,30 @@
+#ifndef IORANGE_H
+#define IORANGE_H
+
+#include <stdint.h>
+
+typedef struct IORange IORange;
+typedef struct IORangeOps IORangeOps;
+
+struct IORangeOps {
+    void (*read)(IORange *iorange, uint64_t offset, unsigned width,
+                 uint64_t *data);
+    void (*write)(IORange *iorange, uint64_t offset, unsigned width,
+                  uint64_t data);
+};
+
+struct IORange {
+    const IORangeOps *ops;
+    uint64_t base;
+    uint64_t len;
+};
+
+static inline void iorange_init(IORange *iorange, const IORangeOps *ops,
+                                uint64_t base, uint64_t len)
+{
+    iorange->ops = ops;
+    iorange->base = base;
+    iorange->len = len;
+}
+
+#endif
-- 
1.7.3.1