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    SubjectRe: [PATCH v2 01/11] kexec: introduce kexec_ops struct
    On 23/11/2012 01:38, H. Peter Anvin wrote:
    > I still don't really get why it can't be isolated from dom0, which would make more sense to me, even for a Xen crash.
    >

    The crash region (as specified by crashkernel= on the Xen command line)
    is isolated from dom0.

    dom0 (using the kexec utility etc) has the task of locating the Xen
    crash notes (using the kexec hypercall interface), constructing a binary
    blob containing kernel, initram and gubbins, and asking Xen to put this
    blob in the crash region (again, using the kexec hypercall interface).

    I do not see how this is very much different from the native case
    currently (although please correct me if I am misinformed). Linux has
    extra work to do by populating /proc/iomem with the Xen crash regions
    boot (so the kexec utility can reference their physical addresses when
    constructing the blob), and should just act as a conduit between the
    kexec system call and the kexec hypercall to load the blob.

    For within-guest kexec/kdump functionality, I agree that it is barking
    mad. However, we do see cloud operators interested in the idea so VM
    administrators can look after their crashes themselves.

    ~Andrew


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