[PATCH v2 3/8] kvm tools: Use ioport context to control blk devices

[Sasha Levin <levinsasha928@gmail.com>]

Since ioports now has the ability to pass context to its
callbacks, we can implement multiple blk devices more efficiently.

We can get a ptr to the 'current' blk dev on each ioport call, which
means that we don't need to keep track of the blk device allocation
and ioport distribution within the module.

The advantages are easier management of multiple blk devices and
removal of any hardcoded limits to the amount of possible blk
devices.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
---
 tools/kvm/include/kvm/ioport.h |    2 -
 tools/kvm/virtio/blk.c         |   75 ++++++++++++++--------------------------
 2 files changed, 26 insertions(+), 51 deletions(-)

diff --git a/tools/kvm/include/kvm/ioport.h b/tools/kvm/include/kvm/ioport.h
index c500f1e..47f9fb5 100644
--- a/tools/kvm/include/kvm/ioport.h
+++ b/tools/kvm/include/kvm/ioport.h
@@ -14,8 +14,6 @@
 #define IOPORT_VESA_SIZE		256
 #define IOPORT_VIRTIO_P9		0xb200	/* Virtio 9P device */
 #define IOPORT_VIRTIO_P9_SIZE		256
-#define IOPORT_VIRTIO_BLK		0xc200	/* Virtio block device */
-#define IOPORT_VIRTIO_BLK_SIZE		0x200
 #define IOPORT_VIRTIO_CONSOLE		0xd200	/* Virtio console device */
 #define IOPORT_VIRTIO_CONSOLE_SIZE	256
 #define IOPORT_VIRTIO_NET		0xe200	/* Virtio network device */
diff --git a/tools/kvm/virtio/blk.c b/tools/kvm/virtio/blk.c
index 25ce61f..cb103fc 100644
--- a/tools/kvm/virtio/blk.c
+++ b/tools/kvm/virtio/blk.c
@@ -14,6 +14,7 @@
 #include <linux/virtio_ring.h>
 #include <linux/virtio_blk.h>
 
+#include <linux/list.h>
 #include <linux/types.h>
 #include <pthread.h>
 
@@ -34,15 +35,16 @@ struct blk_dev_job {
 
 struct blk_dev {
 	pthread_mutex_t			mutex;
+	struct list_head		list;
 
 	struct virtio_blk_config	blk_config;
 	struct disk_image		*disk;
+	u64				base_addr;
 	u32				host_features;
 	u32				guest_features;
 	u16				config_vector;
 	u8				status;
 	u8				isr;
-	u8				idx;
 
 	/* virtio queue */
 	u16				queue_selector;
@@ -52,7 +54,7 @@ struct blk_dev {
 	struct pci_device_header	pci_hdr;
 };
 
-static struct blk_dev *bdevs[VIRTIO_BLK_MAX_DEV];
+static LIST_HEAD(bdevs);
 
 static bool virtio_blk_dev_in(struct blk_dev *bdev, void *data, unsigned long offset, int size, u32 count)
 {
@@ -66,22 +68,14 @@ static bool virtio_blk_dev_in(struct blk_dev *bdev, void *data, unsigned long of
 	return true;
 }
 
-/* Translate port into device id + offset in that device addr space */
-static void virtio_blk_port2dev(u16 port, u16 base, u16 size, u16 *dev_idx, u16 *offset)
-{
-	*dev_idx	= (port - base) / size;
-	*offset		= port - (base + *dev_idx * size);
-}
-
-static bool virtio_blk_pci_io_in(struct kvm *kvm, u16 port, void *data, int size, u32 count)
+static bool virtio_blk_pci_io_in(struct kvm *kvm, u16 port, void *data, int size, u32 count, void *param)
 {
 	struct blk_dev *bdev;
-	u16 offset, dev_idx;
+	u16 offset;
 	bool ret = true;
 
-	virtio_blk_port2dev(port, IOPORT_VIRTIO_BLK, IOPORT_VIRTIO_BLK_SIZE, &dev_idx, &offset);
-
-	bdev = bdevs[dev_idx];
+	bdev	= param;
+	offset	= port - bdev->base_addr;
 
 	mutex_lock(&bdev->mutex);
 
@@ -178,15 +172,14 @@ static void virtio_blk_do_io(struct kvm *kvm, void *param)
 	virt_queue__trigger_irq(vq, bdev->pci_hdr.irq_line, &bdev->isr, kvm);
 }
 
-static bool virtio_blk_pci_io_out(struct kvm *kvm, u16 port, void *data, int size, u32 count)
+static bool virtio_blk_pci_io_out(struct kvm *kvm, u16 port, void *data, int size, u32 count, void *param)
 {
 	struct blk_dev *bdev;
-	u16 offset, dev_idx;
+	u16 offset;
 	bool ret = true;
 
-	virtio_blk_port2dev(port, IOPORT_VIRTIO_BLK, IOPORT_VIRTIO_BLK_SIZE, &dev_idx, &offset);
-
-	bdev = bdevs[dev_idx];
+	bdev	= param;
+	offset	= port - bdev->base_addr;
 
 	mutex_lock(&bdev->mutex);
 
@@ -246,48 +239,29 @@ static bool virtio_blk_pci_io_out(struct kvm *kvm, u16 port, void *data, int siz
 }
 
 static struct ioport_operations virtio_blk_io_ops = {
-	.io_in		= virtio_blk_pci_io_in,
-	.io_out		= virtio_blk_pci_io_out,
+	.io_in_param	= virtio_blk_pci_io_in,
+	.io_out_param	= virtio_blk_pci_io_out,
 };
 
-static int virtio_blk_find_empty_dev(void)
-{
-	int i;
-
-	for (i = 0; i < VIRTIO_BLK_MAX_DEV; i++) {
-		if (bdevs[i] == NULL)
-			return i;
-	}
-
-	return -1;
-}
-
 void virtio_blk__init(struct kvm *kvm, struct disk_image *disk)
 {
 	u16 blk_dev_base_addr;
 	u8 dev, pin, line;
 	struct blk_dev *bdev;
-	int new_dev_idx;
 
 	if (!disk)
 		return;
 
-	new_dev_idx		= virtio_blk_find_empty_dev();
-	if (new_dev_idx < 0)
-		die("Could not find an empty block device slot");
-
-	bdevs[new_dev_idx]	= calloc(1, sizeof(struct blk_dev));
-	if (bdevs[new_dev_idx] == NULL)
+	bdev = calloc(1, sizeof(struct blk_dev));
+	if (bdev == NULL)
 		die("Failed allocating bdev");
 
-	bdev			= bdevs[new_dev_idx];
-
-	blk_dev_base_addr	= IOPORT_VIRTIO_BLK + new_dev_idx * IOPORT_VIRTIO_BLK_SIZE;
+	blk_dev_base_addr	= ioport__register_param(IOPORT_EMPTY, &virtio_blk_io_ops, IOPORT_SIZE, bdev);
 
 	*bdev			= (struct blk_dev) {
 		.mutex				= PTHREAD_MUTEX_INITIALIZER,
 		.disk				= disk,
-		.idx				= new_dev_idx,
+		.base_addr			= blk_dev_base_addr,
 		.blk_config			= (struct virtio_blk_config) {
 			.capacity		= disk->size / SECTOR_SIZE,
 			.seg_max		= DISK_SEG_MAX,
@@ -310,6 +284,8 @@ void virtio_blk__init(struct kvm *kvm, struct disk_image *disk)
 		.host_features			= (1UL << VIRTIO_BLK_F_SEG_MAX | 1UL << VIRTIO_BLK_F_FLUSH),
 	};
 
+	list_add_tail(&bdev->list, &bdevs);
+
 	if (irq__register_device(VIRTIO_ID_BLOCK, &dev, &pin, &line) < 0)
 		return;
 
@@ -317,8 +293,6 @@ void virtio_blk__init(struct kvm *kvm, struct disk_image *disk)
 	bdev->pci_hdr.irq_line	= line;
 
 	pci__register(&bdev->pci_hdr, dev);
-
-	ioport__register(blk_dev_base_addr, &virtio_blk_io_ops, IOPORT_VIRTIO_BLK_SIZE);
 }
 
 void virtio_blk__init_all(struct kvm *kvm)
@@ -331,8 +305,11 @@ void virtio_blk__init_all(struct kvm *kvm)
 
 void virtio_blk__delete_all(struct kvm *kvm)
 {
-	int i;
+	while (!list_empty(&bdevs)) {
+		struct blk_dev *bdev;
 
-	for (i = 0; i < kvm->nr_disks; i++)
-		free(bdevs[i]);
+		bdev = list_first_entry(&bdevs, struct blk_dev, list);
+		list_del(&bdev->list);
+		free(bdev);
+	}
 }
-- 
1.7.5.rc3