[PATCH 2/2 V2] kvm tools: Add MMIO address mapper

[Sasha Levin <levinsasha928@gmail.com>]

When we have a MMIO exit, we need to find which device
has registered to use the accessed MMIO space.

The mapper maps ranges of guest physical addresses to
callback functions.

Implementation is based on an interval red-black tree.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
---
 tools/kvm/include/kvm/kvm.h |    2 +
 tools/kvm/mmio.c            |   79 +++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 79 insertions(+), 2 deletions(-)

diff --git a/tools/kvm/include/kvm/kvm.h b/tools/kvm/include/kvm/kvm.h
index b310d50..d9943bf 100644
--- a/tools/kvm/include/kvm/kvm.h
+++ b/tools/kvm/include/kvm/kvm.h
@@ -44,6 +44,8 @@ void kvm__stop_timer(struct kvm *kvm);
 void kvm__irq_line(struct kvm *kvm, int irq, int level);
 bool kvm__emulate_io(struct kvm *kvm, u16 port, void *data, int direction, int size, u32 count);
 bool kvm__emulate_mmio(struct kvm *kvm, u64 phys_addr, u8 *data, u32 len, u8 is_write);
+bool kvm__register_mmio(u64 phys_addr, u64 phys_addr_len, void (*kvm_mmio_callback_fn)(u64 addr, u8 *data, u32 len, u8 is_write));
+bool kvm__deregister_mmio(u64 phys_addr);
 
 /*
  * Debugging
diff --git a/tools/kvm/mmio.c b/tools/kvm/mmio.c
index 848267d..ef986bf 100644
--- a/tools/kvm/mmio.c
+++ b/tools/kvm/mmio.c
@@ -1,7 +1,48 @@
 #include "kvm/kvm.h"
+#include "kvm/rbtree-interval.h"
 
 #include <stdio.h>
+#include <stdlib.h>
+
 #include <linux/types.h>
+#include <linux/rbtree.h>
+
+#define mmio_node(n) rb_entry(n, struct mmio_mapping, node)
+
+struct mmio_mapping {
+	struct rb_int_node	node;
+	void			(*kvm_mmio_callback_fn)(u64 addr, u8 *data, u32 len, u8 is_write);
+};
+
+static struct rb_root mmio_tree = RB_ROOT;
+
+static struct mmio_mapping *mmio_search(struct rb_root *root, u64 addr, u64 len)
+{
+	struct rb_int_node *node;
+
+	node = rb_int_search_range(root, addr, addr + len);
+	if (node == NULL)
+		return NULL;
+
+	return mmio_node(node);
+}
+
+/* Find lowest match, Check for overlap */
+static struct mmio_mapping *mmio_search_single(struct rb_root *root, u64 addr)
+{
+	struct rb_int_node *node;
+
+	node = rb_int_search_single(root, addr);
+	if (node == NULL)
+		return NULL;
+
+	return mmio_node(node);
+}
+
+static int mmio_insert(struct rb_root *root, struct mmio_mapping *data)
+{
+	return rb_int_insert(root, &data->node);
+}
 
 static const char *to_direction(u8 is_write)
 {
@@ -11,10 +52,44 @@ static const char *to_direction(u8 is_write)
 	return "read";
 }
 
+bool kvm__register_mmio(u64 phys_addr, u64 phys_addr_len, void (*kvm_mmio_callback_fn)(u64 addr, u8 *data, u32 len, u8 is_write))
+{
+	struct mmio_mapping *mmio;
+
+	mmio = malloc(sizeof(*mmio));
+	if (mmio == NULL)
+		return false;
+
+	*mmio = (struct mmio_mapping) {
+		.node = RB_INT_INIT(phys_addr, phys_addr + phys_addr_len),
+		.kvm_mmio_callback_fn = kvm_mmio_callback_fn,
+	};
+
+	return mmio_insert(&mmio_tree, mmio);
+}
+
+bool kvm__deregister_mmio(u64 phys_addr)
+{
+	struct mmio_mapping *mmio;
+
+	mmio = mmio_search_single(&mmio_tree, phys_addr);
+	if (mmio == NULL)
+		return false;
+
+	rb_int_erase(&mmio_tree, &mmio->node);
+	free(mmio);
+	return true;
+}
+
 bool kvm__emulate_mmio(struct kvm *kvm, u64 phys_addr, u8 *data, u32 len, u8 is_write)
 {
-	fprintf(stderr, "Warning: Ignoring MMIO %s at %016llx (length %u)\n",
-		to_direction(is_write), phys_addr, len);
+	struct mmio_mapping *mmio = mmio_search(&mmio_tree, phys_addr, len);
+
+	if (mmio)
+		mmio->kvm_mmio_callback_fn(phys_addr, data, len, is_write);
+	else
+		fprintf(stderr, "Warning: Ignoring MMIO %s at %016llx (length %u)\n",
+			to_direction(is_write), phys_addr, len);
 
 	return true;
 }
-- 
1.7.5.rc3