[PATCH v2 1/8] kvm tools: Add optional parameter used in ioport callbacks

[Sasha Levin <levinsasha928@gmail.com>]

Allow specifying an optional parameter when registering an
ioport range. The callback functions provided by the registering
module will be called with the same parameter.

This may be used to keep context during callbacks on IO operations.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
---
 tools/kvm/include/kvm/ioport.h |    3 ++
 tools/kvm/ioport.c             |   54 +++++++++++++++++++++++++++++----------
 2 files changed, 43 insertions(+), 14 deletions(-)

diff --git a/tools/kvm/include/kvm/ioport.h b/tools/kvm/include/kvm/ioport.h
index 8253938..2a8d74d 100644
--- a/tools/kvm/include/kvm/ioport.h
+++ b/tools/kvm/include/kvm/ioport.h
@@ -25,11 +25,14 @@ struct kvm;
 struct ioport_operations {
 	bool (*io_in)(struct kvm *kvm, u16 port, void *data, int size, u32 count);
 	bool (*io_out)(struct kvm *kvm, u16 port, void *data, int size, u32 count);
+	bool (*io_in_param)(struct kvm *kvm, u16 port, void *data, int size, u32 count, void *param);
+	bool (*io_out_param)(struct kvm *kvm, u16 port, void *data, int size, u32 count, void *param);
 };
 
 void ioport__setup_legacy(void);
 
 void ioport__register(u16 port, struct ioport_operations *ops, int count);
+void ioport__register_param(u16 port, struct ioport_operations *ops, int count, void *param);
 
 static inline u8 ioport__read8(u8 *data)
 {
diff --git a/tools/kvm/ioport.c b/tools/kvm/ioport.c
index 1f13960..159d089 100644
--- a/tools/kvm/ioport.c
+++ b/tools/kvm/ioport.c
@@ -18,6 +18,7 @@
 struct ioport_entry {
 	struct rb_int_node		node;
 	struct ioport_operations	*ops;
+	void				*param;
 };
 
 static struct rb_root ioport_tree = RB_ROOT;
@@ -89,6 +90,29 @@ void ioport__register(u16 port, struct ioport_operations *ops, int count)
 	ioport_insert(&ioport_tree, entry);
 }
 
+void ioport__register_param(u16 port, struct ioport_operations *ops, int count, void *param)
+{
+	struct ioport_entry *entry;
+
+	entry = ioport_search(&ioport_tree, port);
+	if (entry) {
+		pr_warning("ioport re-registered: %x", port);
+		rb_int_erase(&ioport_tree, &entry->node);
+	}
+
+	entry = malloc(sizeof(*entry));
+	if (entry == NULL)
+		die("Failed allocating new ioport entry");
+
+	*entry = (struct ioport_entry) {
+		.node	= RB_INT_INIT(port, port + count),
+		.ops	= ops,
+		.param	= param,
+	};
+
+	ioport_insert(&ioport_tree, entry);
+}
+
 static const char *to_direction(int direction)
 {
 	if (direction == KVM_EXIT_IO_IN)
@@ -105,30 +129,32 @@ static void ioport_error(u16 port, void *data, int direction, int size, u32 coun
 bool kvm__emulate_io(struct kvm *kvm, u16 port, void *data, int direction, int size, u32 count)
 {
 	struct ioport_operations *ops;
-	bool ret;
+	bool ret = false;
 	struct ioport_entry *entry;
+	void *param;
 
 	entry = ioport_search(&ioport_tree, port);
 	if (!entry)
 		goto error;
 
-	ops = entry->ops;
+	ops	= entry->ops;
+	param	= entry->param;
 
 	if (direction == KVM_EXIT_IO_IN) {
-		if (!ops->io_in)
-			goto error;
-
-		ret = ops->io_in(kvm, port, data, size, count);
-		if (!ret)
-			goto error;
+		if (!param && ops->io_in)
+			ret = ops->io_in(kvm, port, data, size, count);
+		if (param && ops->io_in_param)
+			ret = ops->io_in_param(kvm, port, data, size, count, param);
 	} else {
-		if (!ops->io_out)
-			goto error;
-
-		ret = ops->io_out(kvm, port, data, size, count);
-		if (!ret)
-			goto error;
+		if (!param && ops->io_out)
+			ret = ops->io_out(kvm, port, data, size, count);
+		if (param && ops->io_out_param)
+			ret = ops->io_out_param(kvm, port, data, size, count, param);
 	}
+
+	if (!ret)
+		goto error;
+
 	return true;
 error:
 	if (ioport_debug)
-- 
1.7.5.rc3