[PATCH 0/9] kvm: s390: Add PV dump support

Janosch Frank
2022-04-28T13:05:45Z

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.

I chose not to document the dump data provided by the Ultravisor since
KVM doesn't interprete it in any way. We're currently searching for a
location and enough cycles to make it available to all.

v4:
* Rebased and fixed up conflicts due to the Documentation
changes and new KVM capabilities
* Fixed the dump facility check, now we check for all 4 calls

v3:
* Added Rev-by
* Renamed the query function's len variables to len_min

v2:
* Added vcpu SIE blocking to avoid validities
* Moved the KVM CAP to patch #7
* Renamed len to len_max and introduced len_written for extendability
* Added Rev-bys

Janosch Frank (9):
s390x: Add SE hdr query information
s390: uv: Add dump fields to query
KVM: s390: pv: Add query interface
KVM: s390: pv: Add dump support definitions
KVM: s390: pv: Add query dump information
kvm: s390: Add configuration dump functionality
kvm: s390: Add CPU dump functionality
Documentation: virt: Protected virtual machine dumps
Documentation/virt/kvm/api.rst: Add protvirt dump/info api
descriptions

Documentation/virt/kvm/api.rst | 152 ++++++++-
Documentation/virt/kvm/s390/index.rst | 1 +
Documentation/virt/kvm/s390/s390-pv-dump.rst | 60 ++++
arch/s390/boot/uv.c | 4 +
arch/s390/include/asm/kvm_host.h | 1 +
arch/s390/include/asm/uv.h | 45 ++-
arch/s390/kernel/uv.c | 53 ++++
arch/s390/kvm/kvm-s390.c | 306 +++++++++++++++++++
arch/s390/kvm/kvm-s390.h | 3 +
arch/s390/kvm/pv.c | 131 ++++++++
include/uapi/linux/kvm.h | 55 ++++
11 files changed, 808 insertions(+), 3 deletions(-)
create mode 100644 Documentation/virt/kvm/s390/s390-pv-dump.rst

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