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    SubjectRe: OMAP and MSM IOMMU driver misbehavior
    On 1/23/2012 6:03 AM, Joerg Roedel wrote:
    > Hi,
    >
    > while reviewing another IOMMU driver again I came across a problem in
    > the IOMMU drivers for OMAP and MSM platforms. In both drivers the
    > 'domain_destroy with devices attached' case isn't handled correctly.
    >
    > OMAP driver seems not to track the devices attached to a domain at all.
    > So when a domain is destroyed it can happen that the hardware still
    > references old (and already freed) page-table pointers.
    >
    > MSM tracks devices in a domain, but does not automatically remove the
    > devices from a domain that is about to be destroyed.
    >
    > Please tell me when I mis-read the code, otherwise please fix this in
    > your drivers so that we can get consistent behavior for IOMMU-API
    > users :-)
    >
    > Thanks,
    >
    > Joerg

    Hello

    I believe your analysis is correct, and it is a legitimate problem. The
    driver does keep a list of devices attached to a domain, so it should
    not be too hard to detach them. However, I have been quite occupied with
    other things lately, but I can try to get to it when I have some free
    time. Calling detach_dev on each element is what needs to happen in
    theory, but I feel like the main detach_dev code will need to be broken
    out to handle the locking properly. Still, it does not sound
    particularly difficult.

    Steve



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