Re: [Xen-devel] DMA trouble with current xen-sparse

[Vincent Hanquez <vincent.hanquez@xxxxxxxxxxxx>]

On Wed, Nov 02, 2005 at 06:04:25PM -0500, Daniel Veillard wrote:
>   I'm not a kernel hacker, but if you give me a patch displaying those
> informations at the IOMMU_BUG_ON pointed by Steven, I will gladly rebuild 
> and try to reboot over it to give you the informations (I have no serial
> so hint on avoiding the instant reboot of the dom0 would help). Oh yeah
> it's just dom0 on top of the hypervisor, no domU even started.

Hi Daniel,

could you try the following patch just to have a bit more information
about the pointer and the size ?

diff -r ca2e91ab4311 linux-2.6-xen-sparse/arch/xen/i386/kernel/pci-dma.c
--- a/linux-2.6-xen-sparse/arch/xen/i386/kernel/pci-dma.c       Thu Nov  3 
01:45:07 2005
+++ b/linux-2.6-xen-sparse/arch/xen/i386/kernel/pci-dma.c       Wed Nov  2 
21:32:34 2005
@@ -267,6 +267,8 @@
                dma = swiotlb_map_single(dev, ptr, size, direction);
        } else {
                dma = virt_to_bus(ptr);
+               if (range_straddles_page_boundary(ptr, size))
+                       printk("ptr: %p %zd\n", ptr, size);
                IOMMU_BUG_ON(range_straddles_page_boundary(ptr, size));
                IOMMU_BUG_ON(address_needs_mapping(dev, dma));
        }


stick a while (1) ; after the printk would help you to avoid the reboot
something like:

if (range_straddles_page_boundary(ptr, size)) {
        printk("ptr: %p %zd\n", ptr, size);
        while (1);
}

Cheers,
-- 
Vincent Hanquez

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