kvm: Setup disk geometry if needed

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>

blk-virtio.c

@@ -230,8 +230,16 @@ static struct pci_device_header blk_virtio_pci_device = {
 	.irq_line		= VIRTIO_BLK_IRQ,
 };
 
-void blk_virtio__init(void)
+void blk_virtio__init(struct kvm *self)
 {
+	/* update disk geometry */
+	if (self->disk_image) {
+		device.blk_config.capacity		= self->disk_image->size;
+		device.blk_config.geometry.cylinders	= self->disk_image->cylinders;
+		device.blk_config.geometry.heads	= self->disk_image->heads;
+		device.blk_config.geometry.sectors	= self->disk_image->sectors;
+	}
+
 	pci__register(&blk_virtio_pci_device, 1);
 
 	ioport__register(IOPORT_VIRTIO, &blk_virtio_io_ops, 256);

disk-image.c

@@ -17,6 +17,7 @@ struct disk_image *disk_image__open(const char *filename)
 {
 	struct disk_image *self;
 	struct stat st;
+	int cylinders, heads, sectors;
 
 	self		= malloc(sizeof *self);
 	if (!self)
@@ -35,6 +36,36 @@ struct disk_image *disk_image__open(const char *filename)
 	if (self->mmap == MAP_FAILED)
 		goto failed_close_fd;
 
+	/*
+	 * set the standart disk geometry of the image
+	 *
+	 * real disk example
+	 * Disk /dev/sda: 500.1 GB, 500107862016 bytes
+	 * 255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors
+	 */
+	cylinders = (self->size >> SECTOR_SHIFT) / 16383;
+	if (cylinders > 16383)
+		cylinders = 16383;
+	else if (cylinders < 2)
+		cylinders = 2;
+	heads = (self->size >> SECTOR_SHIFT) / cylinders;
+	if (heads > 255)
+		heads = 255;
+	else if (heads < 1)
+		heads = 1;
+	sectors = (self->size >> SECTOR_SHIFT) / cylinders / heads;
+	if (sectors > 255)
+		sectors = 255;
+	else if (sectors < 1)
+		sectors = 1;
+
+	self->sectors	= sectors;
+	self->heads	= heads;
+	self->cylinders	= cylinders;
+
+	info("block image geometry: sectors: %d heads: %d cylinders: %d",
+		sectors, heads, cylinders);
+
 	return self;
 
 failed_close_fd:

include/kvm/blk-virtio.h

@@ -1,6 +1,8 @@
 #ifndef KVM__BLK_VIRTIO_H
 #define KVM__BLK_VIRTIO_H
 
-void blk_virtio__init(void);
+struct kvm;
+
+void blk_virtio__init(struct kvm *self);
 
 #endif /* KVM__BLK_VIRTIO_H */

include/kvm/disk-image.h

@@ -7,6 +7,10 @@ struct disk_image {
 	void		*mmap;
 	int		fd;
 	uint64_t	size;
+
+	uint16_t	cylinders;
+	uint8_t		heads;
+	uint8_t		sectors;
 };
 
 struct disk_image *disk_image__open(const char *filename);

main.c

@@ -134,7 +134,7 @@ int main(int argc, char *argv[])
 	pci__init();
 
 	if (enable_virtio)
-		blk_virtio__init();
+		blk_virtio__init(kvm);
 
 	for (;;) {
 		kvm__run(kvm);