@@ -198,7 +198,8 @@ static int vpc_open(BlockDriverState *bs, int flags)
bs->total_sectors = (int64_t)
be16_to_cpu(footer->cyls) * footer->heads * footer->secs_per_cyl;
- if (bs->total_sectors >= 65535 * 16 * 255) {
+ /* Allow a maximum disk size of approximately 2 TB */
+ if (bs->total_sectors >= 65535LL * 255 * 255) {
err = -EFBIG;
goto fail;
}
@@ -524,19 +525,27 @@ static coroutine_fn int vpc_co_write(BlockDriverState *bs, int64_t sector_num,
* Note that the geometry doesn't always exactly match total_sectors but
* may round it down.
*
- * Returns 0 on success, -EFBIG if the size is larger than 127 GB
+ * Returns 0 on success, -EFBIG if the size is larger than ~2 TB. Override
+ * the hardware EIDE and ATA-2 limit of 16 heads (max disk size of 127 GB)
+ * and instead allow up to 255 heads.
*/
static int calculate_geometry(int64_t total_sectors, uint16_t* cyls,
uint8_t* heads, uint8_t* secs_per_cyl)
{
uint32_t cyls_times_heads;
- if (total_sectors > 65535 * 16 * 255)
+ /* Allow a maximum disk size of approximately 2 TB */
+ if (total_sectors > 65535LL * 255 * 255) {
return -EFBIG;
+ }
if (total_sectors > 65535 * 16 * 63) {
*secs_per_cyl = 255;
- *heads = 16;
+ if (total_sectors > 65535 * 16 * 255) {
+ *heads = 255;
+ } else {
+ *heads = 16;
+ }
cyls_times_heads = total_sectors / *secs_per_cyl;
} else {
*secs_per_cyl = 17;
The VHD specification allows for up to a 2 TB disk size. The current implementation in qemu emulates EIDE and ATA-2 hardware which only allows for up to 127 GB. This disk size limitation can be overridden by allowing up to 255 heads instead of the normal 4 bit limitation of 16. Doing so allows disk images to be created of up to nearly 2 TB. This change does not violate the VHD format specification nor does it change how smaller disks (ie, <=127GB) are defined. Signed-off-by: Charles Arnold <carnold@suse.com>