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    SubjectRe: [PATCH] scsi: virtio-scsi: Fix address translation failure of HighMem pages used by sg list
    Il 25/07/2012 15:26, Boaz Harrosh ha scritto:
    > On 07/25/2012 03:49 PM, Paolo Bonzini wrote:
    >> Except here the destination array has to be given to virtio, which
    >> doesn't (yet) understand chaining. I'm using for_each_sg rather than a
    >> simple memcpy exactly because I want to flatten the input scatterlist
    >> onto consecutive scatterlist entries, which is what virtio expects (and
    >> what I'll change when I get to it).
    >> for_each_sg guarantees that I get non-chain scatterlists only, so it is
    >> okay to value-assign them to sg[].
    > So if the virtio does not understand chaining at all then surly it will
    > not understand the 2-bit end marker and will get a wrong page pointer
    > with the 1st bit set.

    It doesn't understand chaining, but it does use sg_phys(x) so it will
    not get a wrong page pointer for the end marker.

    > Fine then your code is now a crash because the terminating bit was just
    > copied over, which it was not before.

    I did test the patch with value-assignment.

    > Lets separate the two topics from now on. Send me one mail concerning
    > the proper above patch, And a different mail for how to support chaining.

    Ok, and I'll change the topic.


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