[PATCH v2 2/8] kvm tools: Add basic ioport dynamic allocation

[Sasha Levin <levinsasha928@gmail.com>]

Add a very simple allocation of ioports.

This prevents the need to coordinate ioports between different
modules.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
---
 tools/kvm/include/kvm/ioport.h |   11 +++++++++--
 tools/kvm/ioport.c             |   36 ++++++++++++++++++++++++++++++++++--
 2 files changed, 43 insertions(+), 4 deletions(-)

diff --git a/tools/kvm/include/kvm/ioport.h b/tools/kvm/include/kvm/ioport.h
index 2a8d74d..c500f1e 100644
--- a/tools/kvm/include/kvm/ioport.h
+++ b/tools/kvm/include/kvm/ioport.h
@@ -7,6 +7,9 @@
 
 /* some ports we reserve for own use */
 #define IOPORT_DBG			0xe0
+#define IOPORT_START			0x6200
+#define IOPORT_SIZE			0x400
+
 #define IOPORT_VESA			0xa200
 #define IOPORT_VESA_SIZE		256
 #define IOPORT_VIRTIO_P9		0xb200	/* Virtio 9P device */
@@ -20,6 +23,8 @@
 #define IOPORT_VIRTIO_RNG		0xf200	/* Virtio network device */
 #define IOPORT_VIRTIO_RNG_SIZE		256
 
+#define IOPORT_EMPTY			USHRT_MAX
+
 struct kvm;
 
 struct ioport_operations {
@@ -31,8 +36,10 @@ struct ioport_operations {
 
 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);
+u16 ioport__register(u16 port, struct ioport_operations *ops, int count);
+u16 ioport__register_param(u16 port, struct ioport_operations *ops, int count, void *param);
+
+u16 ioport__find_free_range(void);
 
 static inline u8 ioport__read8(u8 *data)
 {
diff --git a/tools/kvm/ioport.c b/tools/kvm/ioport.c
index 159d089..b2a3272 100644
--- a/tools/kvm/ioport.c
+++ b/tools/kvm/ioport.c
@@ -3,6 +3,7 @@
 #include "kvm/kvm.h"
 #include "kvm/util.h"
 #include "kvm/rbtree-interval.h"
+#include "kvm/mutex.h"
 
 #include <linux/kvm.h>	/* for KVM_EXIT_* */
 #include <linux/types.h>
@@ -21,9 +22,23 @@ struct ioport_entry {
 	void				*param;
 };
 
+static u16 free_io_port_idx;
+DEFINE_MUTEX(free_io_port_idx_lock);
 static struct rb_root ioport_tree = RB_ROOT;
 bool ioport_debug;
 
+static u16 ioport__find_free_port(void)
+{
+	u16 free_port;
+
+	mutex_lock(&free_io_port_idx_lock);
+	free_port = IOPORT_START + free_io_port_idx * IOPORT_SIZE;
+	free_io_port_idx++;
+	mutex_unlock(&free_io_port_idx_lock);
+
+	return free_port;
+}
+
 static struct ioport_entry *ioport_search(struct rb_root *root, u64 addr)
 {
 	struct rb_int_node *node;
@@ -68,10 +83,13 @@ static struct ioport_operations dummy_write_only_ioport_ops = {
 	.io_out		= dummy_io_out,
 };
 
-void ioport__register(u16 port, struct ioport_operations *ops, int count)
+u16 ioport__register(u16 port, struct ioport_operations *ops, int count)
 {
 	struct ioport_entry *entry;
 
+	if (port == IOPORT_EMPTY)
+		port = ioport__find_free_port();
+
 	entry = ioport_search(&ioport_tree, port);
 	if (entry) {
 		pr_warning("ioport re-registered: %x", port);
@@ -88,12 +106,17 @@ void ioport__register(u16 port, struct ioport_operations *ops, int count)
 	};
 
 	ioport_insert(&ioport_tree, entry);
+
+	return port;
 }
 
-void ioport__register_param(u16 port, struct ioport_operations *ops, int count, void *param)
+u16 ioport__register_param(u16 port, struct ioport_operations *ops, int count, void *param)
 {
 	struct ioport_entry *entry;
 
+	if (port == IOPORT_EMPTY)
+		port = ioport__find_free_port();
+
 	entry = ioport_search(&ioport_tree, port);
 	if (entry) {
 		pr_warning("ioport re-registered: %x", port);
@@ -111,6 +134,8 @@ void ioport__register_param(u16 port, struct ioport_operations *ops, int count,
 	};
 
 	ioport_insert(&ioport_tree, entry);
+
+	return port;
 }
 
 static const char *to_direction(int direction)
@@ -126,6 +151,13 @@ static void ioport_error(u16 port, void *data, int direction, int size, u32 coun
 	fprintf(stderr, "IO error: %s port=%x, size=%d, count=%u\n", to_direction(direction), port, size, count);
 }
 
+u16 ioport__find_free_range(void)
+{
+	static u16 cur_loc;
+
+	return IOPORT_START + (cur_loc++ * IOPORT_SIZE);
+}
+
 bool kvm__emulate_io(struct kvm *kvm, u16 port, void *data, int direction, int size, u32 count)
 {
 	struct ioport_operations *ops;
-- 
1.7.5.rc3