[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] rombios: add support for special CHS layout (spt=32)




On 2012-12-07 19:27, Jan Beulich wrote:
On 07.12.12 at 04:25, DuanZhenzhong <zhenzhong.duan@xxxxxxxxxx> wrote:
When booting up windows VM which converted by dd scsi disk, it fails with
"Error Loading Operating System", root cause is rombios doesn't simulate
disk's
logical CHS properly. Real bios uses spt=32 here.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@xxxxxxxxxx>
--- a/tools/firmware/rombios/rombios.c  2011-12-09 00:50:28.000000000 +0800
+++ b/tools/firmware/rombios/rombios.c  2012-11-20 09:42:50.000000000 +0800
@@ -2674,6 +2674,8 @@ void ata_detect( )
        Bit32u sectors_low, sectors_high;
        Bit16u cylinders, heads, spt, blksize;
        Bit8u  translation, removable, mode;
+      Bit8u i;
+      Bit8u *p;
// default mode to PIO16
        mode = ATA_MODE_PIO16;
@@ -2738,14 +2740,32 @@ void ata_detect( )
          case ATA_TRANSLATION_NONE:
            break;
          case ATA_TRANSLATION_LBA:
-          spt = 63;
-          sectors_low /= 63;
-          heads = sectors_low / 1024;
-          if (heads>128) heads = 255;
-          else if (heads>64) heads = 128;
-          else if (heads>32) heads = 64;
-          else if (heads>16) heads = 32;
-          else heads=16;
+          spt = heads = 0;
+          if (ata_cmd_data_in(device,ATA_CMD_READ_SECTORS, 1, 0, 0, 1, 0L, 0L, 
get_SS(),buffer) !=0 )
+            BX_PANIC("ata-detect: Failed to read first sector\n");
+          for(i=0; i<4; i++) {
+            p = buffer + 0x1be + i * 16;
+            if (read_dword(get_SS(), p+12) && read_byte(get_SS(), p+5)) {
+              /* We make the assumption that the partition terminates on
+                 a cylinder boundary */
Which certainly isn't a generally correct assumption, so I strongly
recommend against basing any decisions on that.

Jan
Thanks for comment. Are we the first facing this bug?
Is there any workaround for this issue?
zduan

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel


 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.