[v5,00/10] kvm: s390: Add PV dump support

Message

Janosch Frank May 16, 2022, 9:08 a.m. UTC

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.

v5:
	* v4 went out without a version
	* Fixed spelling mistake in query
	* Improved the storage state dump code
	* Switched to the scheduling uv call for all dump commands
	* Fixed the documentation formatting
	* Moved the capability into its own patch it shouldn't be part of patch #6

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 (10):
  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
  kvm: s390: Add KVM_CAP_S390_PROTECTED_DUMP
  Documentation: virt: Protected virtual machine dumps
  Documentation/virt/kvm/api.rst: Add protvirt dump/info api
    descriptions

 Documentation/virt/kvm/api.rst               | 153 +++++++++-
 Documentation/virt/kvm/s390/index.rst        |   1 +
 Documentation/virt/kvm/s390/s390-pv-dump.rst |  64 ++++
 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                           | 129 ++++++++
 include/uapi/linux/kvm.h                     |  55 ++++
 11 files changed, 811 insertions(+), 3 deletions(-)
 create mode 100644 Documentation/virt/kvm/s390/s390-pv-dump.rst