RE: iommu support on AMD64

[Jerone Young <jyoung5@us.ibm.com>]

On Thu, 2005-09-29 at 15:26 -0500, Langsdorf, Mark wrote:
> > Langsdorf, Mark wrote:
> > > I'm working on getting IOMMU support enabled
> > > for AMD64 in Xen.
> > > 
> > > The current aperture.c code in dom0 requires
> > > several calls to read_pci_config() to find
> > > the AMD northbridge.  These calls are causing
> > > my system to crash.
> > 
> > Can you be more specific (output from serial connection, for 
> > example)? The outl instruction causes #GP, and the emulator 
> > in Xen handle it. So, it's possible the emulator has a bug?
> 
> The serial console is pretty broken on AMD64.  I was
> hoping to not have to debug the serial console in
> order to fix the IOMMU problem.

Do you mean on your machine? Serial console works fine on my AMD64
boxes.

Try this in your grub.conf:

title Xen
        kernel /boot/xen.gz dom0_mem=512000 acpi=off
com1=19200,8n1,0x3f8,4 console=com1 verbose=y sync_console
        module /boot/vmlinuz-2.6.12-xen0 root=/dev/sda1 debug=y
        module /boot/initrd-2.6.12-xen0.img

> 
> Here's the last page or two of messages on my screen:
> (all lines prefixed with (XEN))  I hand copied it but
> all the values are correct.
> 
> *** LOADING DOMAIN 0 ***
> Xen-ELF header found:
> 'GUEST_OS=linux,GUEST_VER=2.6,XEN_VER=3.0,VIRT_BASE=0xffffffff80000000,L
> OADER=generic'
> PHYSICAL MEMORY ARRANGEMENT:
>  Dom0 alloc.: 0000000007000000->0000000008000000 (258048 pages to be
> allocated)
> VIRTUAL MEMORY ARRANGEMNET:
>  Loaded kernel: ffffffff80100000->ffffffff8063e086
>  Init. ramdisk: ffffffff8063f000->ffffffff8063f000
>  Phys-Mach map: ffffffff8063f000->ffffffff8063f000
>  Start info:    ffffffff8063f000->ffffffff80840000
>  Page tables:   ffffffff80840000->ffffffff80849000
>  Boot stack:    ffffffff80849000->ffffffff8084a000
>  TOTAL:         ffffffff80000000->ffffffff80c00000
>  ENTRY ADDRESS: ffffffff80100000
> Scrubbing Free RAM: .................................done.
> *** Serial input -> DOM0 (type 'CTRL-a' three times to switch input to
> Xen).
> Domain 0 (vcpu#0) crashed on cpu#0:
> CPU:	0
> RIP:	e033:[<fffffff80600cc2>]
> RFLAGS:	000000000000286	  CONTEXT: guest
> rax: 000000008000c300	rbx: 000000000000c000	rcx: 0000000000007fff
> rdx: 0000000000000cf8	rsi: 00000000000007e5	rdi: ffffffff804d2be0
> rbp: 0000000000000018	rsp: ffffffff805f5ea0	r8:  000000o000000034
> r9:  0000000000000000	r10: 00000000ffffffff	r11: 0000000o00000000
> r12: 0000000000000cf8	r13: 0000000000000cfc	r14: 00000000o00d2000
> r15: ffffffff804ca200	cr0: 000000008005003b	cr3: 0000000007101000
> Guest stack trace from rsp=ffffffff805f5ea0:
>   (guest stack omitted because it's basically the above registers)
> Domain 0 shutdown: rebooting machine.
> 
> Is there a way to turn on more debug information inside the hypervisor
> itself?
> 
> -Mark Langsdorf
> AMD, Inc.
> 
> 
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> 
-- 
Jerone Young
IBM Linux Technology Center
jyoung5@us.ibm.com
512-838-1157 (T/L: 678-1157)