WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

[Xen-devel] [PATCH v2 3/6] xen-blkfront: handle Xen major numbers other

From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>

This patch makes sure blkfront handles correctly virtual device numbers
corresponding to Xen emulated IDE and SCSI disks: in those cases
blkfront translates the major number to XENVBD and the minor number to a
low xvd minor.

Note: this behaviour is different from what old xenlinux PV guests used
to do: they used to steal an IDE or SCSI major number and use it
instead.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Acked-by: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
---
 drivers/block/xen-blkfront.c     |   79 +++++++++++++++++++++++++++++++++++--
 include/xen/interface/io/blkif.h |   21 ++++++++++
 2 files changed, 95 insertions(+), 5 deletions(-)

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index d7aa39e..64d9c6d 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -120,6 +120,10 @@ static DEFINE_SPINLOCK(minor_lock);
 #define EXTENDED (1<<EXT_SHIFT)
 #define VDEV_IS_EXTENDED(dev) ((dev)&(EXTENDED))
 #define BLKIF_MINOR_EXT(dev) ((dev)&(~EXTENDED))
+#define EMULATED_HD_DISK_MINOR_OFFSET (0)
+#define EMULATED_HD_DISK_NAME_OFFSET (EMULATED_HD_DISK_MINOR_OFFSET / 256)
+#define EMULATED_SD_DISK_MINOR_OFFSET (EMULATED_HD_DISK_MINOR_OFFSET + (4 * 
16))
+#define EMULATED_SD_DISK_NAME_OFFSET (EMULATED_HD_DISK_NAME_OFFSET + 4)
 
 #define DEV_NAME       "xvd"   /* name in /dev */
 
@@ -434,6 +438,65 @@ static void xlvbd_flush(struct blkfront_info *info)
               info->feature_flush ? "enabled" : "disabled");
 }
 
+static int xen_translate_vdev(int vdevice, int *minor, unsigned int *offset)
+{
+       int major;
+       major = BLKIF_MAJOR(vdevice);
+       *minor = BLKIF_MINOR(vdevice);
+       switch (major) {
+               case XEN_IDE0_MAJOR:
+                       *offset = (*minor / 64) + EMULATED_HD_DISK_NAME_OFFSET;
+                       *minor = ((*minor / 64) * PARTS_PER_DISK) +
+                               EMULATED_HD_DISK_MINOR_OFFSET;
+                       break;
+               case XEN_IDE1_MAJOR:
+                       *offset = (*minor / 64) + 2 + 
EMULATED_HD_DISK_NAME_OFFSET;
+                       *minor = (((*minor / 64) + 2) * PARTS_PER_DISK) +
+                               EMULATED_HD_DISK_MINOR_OFFSET;
+                       break;
+               case XEN_SCSI_DISK0_MAJOR:
+                       *offset = (*minor / PARTS_PER_DISK) + 
EMULATED_SD_DISK_NAME_OFFSET;
+                       *minor = *minor + EMULATED_SD_DISK_MINOR_OFFSET;
+                       break;
+               case XEN_SCSI_DISK1_MAJOR:
+               case XEN_SCSI_DISK2_MAJOR:
+               case XEN_SCSI_DISK3_MAJOR:
+               case XEN_SCSI_DISK4_MAJOR:
+               case XEN_SCSI_DISK5_MAJOR:
+               case XEN_SCSI_DISK6_MAJOR:
+               case XEN_SCSI_DISK7_MAJOR:
+                       *offset = (*minor / PARTS_PER_DISK) + 
+                               ((major - XEN_SCSI_DISK1_MAJOR + 1) * 16) +
+                               EMULATED_SD_DISK_NAME_OFFSET;
+                       *minor = *minor +
+                               ((major - XEN_SCSI_DISK1_MAJOR + 1) * 16 * 
PARTS_PER_DISK) +
+                               EMULATED_SD_DISK_MINOR_OFFSET;
+                       break;
+               case XEN_SCSI_DISK8_MAJOR:
+               case XEN_SCSI_DISK9_MAJOR:
+               case XEN_SCSI_DISK10_MAJOR:
+               case XEN_SCSI_DISK11_MAJOR:
+               case XEN_SCSI_DISK12_MAJOR:
+               case XEN_SCSI_DISK13_MAJOR:
+               case XEN_SCSI_DISK14_MAJOR:
+               case XEN_SCSI_DISK15_MAJOR:
+                       *offset = (*minor / PARTS_PER_DISK) + 
+                               ((major - XEN_SCSI_DISK8_MAJOR + 8) * 16) +
+                               EMULATED_SD_DISK_NAME_OFFSET;
+                       *minor = *minor +
+                               ((major - XEN_SCSI_DISK8_MAJOR + 8) * 16 * 
PARTS_PER_DISK) +
+                               EMULATED_SD_DISK_MINOR_OFFSET;
+                       break;
+               case XENVBD_MAJOR:
+                       *offset = *minor / PARTS_PER_DISK;
+                       break;
+               default:
+                       printk(KERN_WARNING "blkfront: your disk configuration 
is "
+                                       "incorrect, please use an xvd device 
instead\n");
+                       return -ENODEV;
+       }
+       return 0;
+}
 
 static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
                               struct blkfront_info *info,
@@ -441,7 +504,7 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
 {
        struct gendisk *gd;
        int nr_minors = 1;
-       int err = -ENODEV;
+       int err;
        unsigned int offset;
        int minor;
        int nr_parts;
@@ -456,12 +519,20 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
        }
 
        if (!VDEV_IS_EXTENDED(info->vdevice)) {
-               minor = BLKIF_MINOR(info->vdevice);
-               nr_parts = PARTS_PER_DISK;
+               err = xen_translate_vdev(info->vdevice, &minor, &offset);
+               if (err)
+                       return err;             
+               nr_parts = PARTS_PER_DISK;
        } else {
                minor = BLKIF_MINOR_EXT(info->vdevice);
                nr_parts = PARTS_PER_EXT_DISK;
+               offset = minor / nr_parts;
+               if (xen_hvm_domain() && offset <= EMULATED_HD_DISK_NAME_OFFSET 
+ 4)
+                       printk(KERN_WARNING "blkfront: vdevice 0x%x might 
conflict with "
+                                       "emulated IDE disks,\n\t choose an xvd 
device name"
+                                       "from xvde on\n", info->vdevice);
        }
+       err = -ENODEV;
 
        if ((minor % nr_parts) == 0)
                nr_minors = nr_parts;
@@ -475,8 +546,6 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
        if (gd == NULL)
                goto release;
 
-       offset = minor / nr_parts;
-
        if (nr_minors > 1) {
                if (offset < 26)
                        sprintf(gd->disk_name, "%s%c", DEV_NAME, 'a' + offset);
diff --git a/include/xen/interface/io/blkif.h b/include/xen/interface/io/blkif.h
index c2d1fa4..68dd2b4 100644
--- a/include/xen/interface/io/blkif.h
+++ b/include/xen/interface/io/blkif.h
@@ -91,4 +91,25 @@ DEFINE_RING_TYPES(blkif, struct blkif_request, struct 
blkif_response);
 #define VDISK_REMOVABLE    0x2
 #define VDISK_READONLY     0x4
 
+/* Xen-defined major numbers for virtual disks, they look strangely
+ * familiar */
+#define XEN_IDE0_MAJOR 3
+#define XEN_IDE1_MAJOR 22
+#define XEN_SCSI_DISK0_MAJOR   8
+#define XEN_SCSI_DISK1_MAJOR   65
+#define XEN_SCSI_DISK2_MAJOR   66
+#define XEN_SCSI_DISK3_MAJOR   67
+#define XEN_SCSI_DISK4_MAJOR   68
+#define XEN_SCSI_DISK5_MAJOR   69
+#define XEN_SCSI_DISK6_MAJOR   70
+#define XEN_SCSI_DISK7_MAJOR   71
+#define XEN_SCSI_DISK8_MAJOR   128
+#define XEN_SCSI_DISK9_MAJOR   129
+#define XEN_SCSI_DISK10_MAJOR  130
+#define XEN_SCSI_DISK11_MAJOR  131
+#define XEN_SCSI_DISK12_MAJOR  132
+#define XEN_SCSI_DISK13_MAJOR  133
+#define XEN_SCSI_DISK14_MAJOR  134
+#define XEN_SCSI_DISK15_MAJOR  135
+
 #endif /* __XEN_PUBLIC_IO_BLKIF_H__ */
-- 
1.5.6.5


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel