[Xen-devel] iommu support on AMD64

["Langsdorf, Mark" <mark.langsdorf@xxxxxxx>]

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.

read_pci_config() is defined in 
linux-2.6.12-xen0/include/asm-x86_64/pci-direct.h
as

static inline u32 read_pci_config(u8 bus, u8 slot, u8 func, u8 offset)
{
        u32 v;
        outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset,
0xcf8);
        v = inl(0xcfc);
        if (v != 0xffffffff)
                PDprintk("%x reading 4 from %x: %x\n", slot, offset, v);
        return v;
}

This a specialized function intended for PCI access 
early in the boot before the PCI subsystem starts 
working.

How can I find the AMD northbridge(s) early in the
dom0 boot sequence without crashing the system?

-Mark Langsdorf
AMD, Inc.


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