I'm trying to debug an issue with qemu 1.7, when altmbr.bin from syslinux is unable to boot from a logical partition when qemu emulates sata drive, but works just fine with ide drive.
While debugging, I noticed that sata drive has some other interesting glitches too. qemu-system-x86_64 -enable-kvm \ -fda hdt-0.5.2.img -boot a \ -device ahci,id=ahci \ -drive file=a_windows_test_image,if=none,id=drv \ -device ide-drive,drive=drv,bus=ahci.0 >From there, choose Disks, Disk1. And qemu will spew this: KVM internal error. Suberror: 1 emulation failure EAX=00000000 EBX=00000000 ECX=f000ff53 EDX=0024bd00 ESI=00000000 EDI=00000000 EBP=00000007 ESP=07fc5fd4 EIP=f000ff53 EFL=00010286 [--S--P-] CPL=0 II=0 A20=1 SMM=0 HLT=0 ES =0028 00000000 ffffffff 00c09300 DPL=0 DS [-WA] CS =0020 00000000 ffffffff 00c09b00 DPL=0 CS32 [-RA] SS =0028 00000000 ffffffff 00c09300 DPL=0 DS [-WA] DS =0028 00000000 ffffffff 00c09300 DPL=0 DS [-WA] FS =0000 00000000 ffffffff 00c00000 GS =0000 00000000 ffffffff 00c00000 LDT=0000 00000000 ffffffff 00c00000 TR =0008 00000580 00000067 00008b00 DPL=0 TSS32-busy GDT= 0000b060 0000002f IDT= 00003008 000007ff CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000 DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000 DR3=0000000000000000 DR6=00000000ffff0ff0 DR7=0000000000000400 EFER=0000000000000000 Code=00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <00> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 hdt-0.5.2.img is from syslinux, a hw diagnostics floppy image. I built it from syslinux-4.07, it can be downloaded directly from my page, http://www.corpit.ru/mjt/tmp/hdt-0.5.2.img.gz . Also included there is disk.c32 module which should show just the disks. To use it, hit Esc on the first menu and type "disk.c32" at the boot: prompt. For ahci/sata drive in qemu, disk.c32 shows garbage: boot: disk.c32 DISK 0x80: C/H/S: 255 heads, 1023 cylinders 63 sectors/track, 1 drives EDD: ebios=1, EDD version: 30 16 heads, 16383 cylinders 33554432 sectors, 512 bytes/sector, 63 sectors/track Host bus: , Interface type: For the "Host bus" and "interface type" - there are some unprintable characters in there, different on each attempt, sometimes it is empty like on the above example. When you switch from bus=ahci.0 to bus=ide.0 on the qemu command line above, it all works fine and does not spew any warnings like that about emulation failure. It looks like we have some uninitialized data on sata emulation (in addition to the altmbr issue which I'm investigating further). Thanks, /mjt
