Marc Hartmayer 8fa1b5a00b zdump: dfi: add support to read Protected Virtualization dumps ...

Sometimes dumping a virtual machine from the outside is the only way to
get the data that is needed. This can be the case if a dumping mechanism
like kdump hasn't been configured or data needs to be fetched at a
specific point. Dumping a protected guest from the outside without help
from FW/HW doesn't yield sufficient data to be useful. Hence we have
introduced Protected Virtualization (PV) dump support - also named
confidential dump support.

The confidential dump support works by integrating the firmware into the
dump process. New Ultravisor calls (UVC) are used to initiate the dump
process, dump CPU data, dump memory state and lastly complete the dump
process. The guest's data is fully encrypted and can only be decrypted
by the entity that owns the customer communication key (CCK) for the
dumped guest. The output format is very similar the normal s390 vmcore
ELF format, it's only enriched by new sections where the returned data
from the UVC "Complete Configuration Dump" and the UVC "Dump
Configuration Storage State" is stored. The encrypted CPU data is stored
in a new note type `NT_S390_PV_CPU_DATA`. The old note types do still
exists but without any confidential data stored. The memory data is
stored in the LOAD segment as usual but for PV dumps it's fully AES-XTS
encrypted.

This commit adds support for reading/decrypting PV guest dumps to
zgetdump by introducing a new DFI input module (`dfi_pv_elf.c`). For
specifying the customer communication key a new command line option
`--key` is added.

Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Reviewed-by: Steffen Eiden <seiden@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>

2022-11-03 17:45:38 +01:00

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