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Sometimes dumping inside of a VM fails, is unavailable or doesn't yield the required data. For these occasions we dump the VM from the outside, writing memory and cpu data to a file. Up to now PV guests only supported dumping from the inside of the guest through dumpers like KDUMP. A PV guest can be dumped from the hypervisor but the data will be stale and / or encrypted. To get the actual state of the PV VM we need the help of the Ultravisor who safeguards the VM state. New UV calls have been added to initialize the dump, dump storage state data, dump cpu data and complete the dump process. We expose these calls in this patch via a new UV ioctl command. The sensitive parts of the dump data are encrypted, the dump key is derived from the Customer Communication Key (CCK). This ensures that only the owner of the VM who has the CCK can decrypt the dump data. The memory is dumped / read via a normal export call and a re-import after the dump initialization is not needed (no re-encryption with a dump key). Signed-off-by: Janosch Frank <frankja@linux.ibm.com> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Link: https://lore.kernel.org/r/20220517163629.3443-7-frankja@linux.ibm.com Message-Id: <20220517163629.3443-7-frankja@linux.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.