block: add topology qdev properties

Add three new qdev properties to export block topology information to
the guest.  This is needed to get optimal I/O alignment for RAID arrays
or SSDs.

The options are:

 - physical_block_size to specify the physical block size of the device,
   this is going to increase from 512 bytes to 4096 kilobytes for many
   modern storage devices
 - min_io_size to specify the minimal I/O size without performance impact,
   this is typically set to the RAID chunk size for arrays.
 - opt_io_size to specify the optimal sustained I/O size, this is
   typically the RAID stripe width for arrays.

I decided to not auto-probe these values from blkid which might easily
be possible as I don't know how to deal with these issues on migration.

Note that we specificly only set the physical_block_size, and not the
logial one which is the unit all I/O is described in.  The reason for
that is that IDE does not support increasing the logical block size and
at last for now I want to stick to one meachnisms in queue and allow
for easy switching of transports for a given backing image which would
not be possible if scsi and virtio use real 4k sectors, while ide only
uses the physical block exponent.

To make this more common for the different block drivers introduce a
new BlockConf structure holding all common block properties and a
DEFINE_BLOCK_PROPERTIES macro to add them all together, mirroring
what is done for network drivers.  Also switch over all block drivers
to use it, except for the floppy driver which has weird driveA/driveB
properties and probably won't require any advanced block options ever.

Example usage for a virtio device with 4k physical block size and
8k optimal I/O size:

  -drive file=scratch.img,media=disk,cache=none,id=scratch \
  -device virtio-blk-pci,drive=scratch,physical_block_size=4096,opt_io_size=8192

aliguori: updated patch to take into account BLOCK events

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 13 insertions, 11 deletions

diff --git a/hw/scsi-generic.c b/hw/scsi-generic.c
index f60ad96d79..de778efa3b 100644
--- a/hw/scsi-generic.c
+++ b/hw/scsi-generic.c
@@ -58,6 +58,7 @@ typedef struct SCSIGenericReq {
 struct SCSIGenericState
 {
     SCSIDevice qdev;
+    BlockDriverState *bs;
     int lun;
     int driver_status;
     uint8_t sensebuf[SCSI_SENSE_BUF_SIZE];
@@ -212,7 +213,7 @@ static void scsi_read_data(SCSIDevice *d, uint32_t tag)
         return;
     }
 
-    ret = execute_command(s->qdev.dinfo->bdrv, r, SG_DXFER_FROM_DEV, scsi_read_complete);
+    ret = execute_command(s->bs, r, SG_DXFER_FROM_DEV, scsi_read_complete);
     if (ret == -1) {
         scsi_command_complete(r, -EINVAL);
         return;
@@ -263,7 +264,7 @@ static int scsi_write_data(SCSIDevice *d, uint32_t tag)
         return 0;
     }
 
-    ret = execute_command(s->qdev.dinfo->bdrv, r, SG_DXFER_TO_DEV, scsi_write_complete);
+    ret = execute_command(s->bs, r, SG_DXFER_TO_DEV, scsi_write_complete);
     if (ret == -1) {
         scsi_command_complete(r, -EINVAL);
         return 1;
@@ -357,7 +358,7 @@ static int32_t scsi_send_command(SCSIDevice *d, uint32_t tag,
             qemu_free(r->buf);
         r->buflen = 0;
         r->buf = NULL;
-        ret = execute_command(s->qdev.dinfo->bdrv, r, SG_DXFER_NONE, scsi_command_complete);
+        ret = execute_command(s->bs, r, SG_DXFER_NONE, scsi_command_complete);
         if (ret == -1) {
             scsi_command_complete(r, -EINVAL);
             return 0;
@@ -452,7 +453,7 @@ static void scsi_destroy(SCSIDevice *d)
         r = DO_UPCAST(SCSIGenericReq, req, QTAILQ_FIRST(&s->qdev.requests));
         scsi_remove_request(r);
     }
-    drive_uninit(s->qdev.dinfo);
+    drive_uninit(s->qdev.conf.dinfo);
 }
 
 static int scsi_generic_initfn(SCSIDevice *dev)
@@ -461,26 +462,27 @@ static int scsi_generic_initfn(SCSIDevice *dev)
     int sg_version;
     struct sg_scsi_id scsiid;
 
-    if (!s->qdev.dinfo || !s->qdev.dinfo->bdrv) {
+    if (!s->qdev.conf.dinfo || !s->qdev.conf.dinfo->bdrv) {
         qemu_error("scsi-generic: drive property not set\n");
         return -1;
     }
+    s->bs = s->qdev.conf.dinfo->bdrv;
 
     /* check we are really using a /dev/sg* file */
-    if (!bdrv_is_sg(s->qdev.dinfo->bdrv)) {
+    if (!bdrv_is_sg(s->bs)) {
         qemu_error("scsi-generic: not /dev/sg*\n");
         return -1;
     }
 
     /* check we are using a driver managing SG_IO (version 3 and after */
-    if (bdrv_ioctl(s->qdev.dinfo->bdrv, SG_GET_VERSION_NUM, &sg_version) < 0 ||
+    if (bdrv_ioctl(s->bs, SG_GET_VERSION_NUM, &sg_version) < 0 ||
         sg_version < 30000) {
         qemu_error("scsi-generic: scsi generic interface too old\n");
         return -1;
     }
 
     /* get LUN of the /dev/sg? */
-    if (bdrv_ioctl(s->qdev.dinfo->bdrv, SG_GET_SCSI_ID, &scsiid)) {
+    if (bdrv_ioctl(s->bs, SG_GET_SCSI_ID, &scsiid)) {
         qemu_error("scsi-generic: SG_GET_SCSI_ID ioctl failed\n");
         return -1;
     }
@@ -491,11 +493,11 @@ static int scsi_generic_initfn(SCSIDevice *dev)
     s->qdev.type = scsiid.scsi_type;
     DPRINTF("device type %d\n", s->qdev.type);
     if (s->qdev.type == TYPE_TAPE) {
-        s->qdev.blocksize = get_stream_blocksize(s->qdev.dinfo->bdrv);
+        s->qdev.blocksize = get_stream_blocksize(s->bs);
         if (s->qdev.blocksize == -1)
             s->qdev.blocksize = 0;
     } else {
-        s->qdev.blocksize = get_blocksize(s->qdev.dinfo->bdrv);
+        s->qdev.blocksize = get_blocksize(s->bs);
         /* removable media returns 0 if not present */
         if (s->qdev.blocksize <= 0) {
             if (s->qdev.type == TYPE_ROM || s->qdev.type  == TYPE_WORM)
@@ -522,7 +524,7 @@ static SCSIDeviceInfo scsi_generic_info = {
     .cancel_io    = scsi_cancel_io,
     .get_buf      = scsi_get_buf,
     .qdev.props   = (Property[]) {
-        DEFINE_PROP_DRIVE("drive", SCSIGenericState, qdev.dinfo),
+        DEFINE_BLOCK_PROPERTIES(SCSIGenericState, qdev.conf),
         DEFINE_PROP_END_OF_LIST(),
     },
 };