[PATCH v1 00/14] s390x: virtio-mem support

[David Hildenbrand]

This series is based on:
    [PATCH v2] virtio: kconfig: memory devices are PCI only [1]

I finally found the time (IOW forced myself) to finish virtio-mem
support on s390x. The last RFC was from 2020, so I won't talk about
what changed -- a lot changed in the meantime :)

There is really not much left to do on s390x, because virtio-mem already
implements most things we need today (e.g., early-migration,
unplugged-inaccessible). The biggest part of this series is just doing what
we do with virtio-pci, wiring it up in the machine hotplug handler and ...
well, messing with the physical memory layout where we can now exceed
initial RAM size and have sparsity (memory holes).

I tested a lot of things, including:
 * Memory hotplug/unplug
 * Device hotplug/unplug
 * System resets / reboots
 * Migrate to/from file (including storage attributes under KVM)
 * Basic live migration
 * Basic postcopy live migration

More details on how to use it on s390x -- which is pretty much how
we use it on other architectures, except
s/virtio-mem-pci/virtio-mem-ccw/ --- is in the last patch.

This series introduces a new diag(500) "STORAGE LIMIT" subcode that will
be documented at [2] once this+kernel part go upstream.

There are not many s390x-specific virtio-mem future work items, except:
* Storage attribute migration might be improved
* We might want to reset storage attributes of unplugged memory
  (might or might not be required for upcoming page table reclaim in
   Linux; TBD)

I'll send out the kernel driver bits soon.

[1] https://lkml.kernel.org/r/20240906101658.514470-1-pbonzini@redhat.com
[2] https://gitlab.com/davidhildenbrand/s390x-os-virt-spec

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Thomas Huth <thuth@redhat.com>
Cc: Halil Pasic <pasic@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Eric Farman <farman@linux.ibm.com>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Janosch Frank <frankja@linux.ibm.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Cornelia Huck <cohuck@redhat.com>

David Hildenbrand (14):
  s390x/s390-virtio-ccw: don't crash on weird RAM sizes
  s390x/s390-virtio-hcall: remove hypercall registration mechanism
  s390x/s390-virtio-hcall: prepare for more diag500 hypercalls
  s390x: rename s390-virtio-hcall* to s390-hypercall*
  s390x/s390-virtio-ccw: move setting the maximum guest size from sclp
    to machine code
  s390x: introduce s390_get_memory_limit()
  s390x/s390-hypercall: introduce DIAG500 STORAGE_LIMIT
  s390x/s390-stattrib-kvm: prepare memory devices and sparse memory
    layouts
  s390x/s390-skeys: prepare for memory devices
  s390x/pv: check initial, not maximum RAM size
  s390x/s390-virtio-ccw: prepare for memory devices
  s390x: introduce s390_get_max_pagesize()
  s390x/virtio-ccw: add support for virtio based memory devices
  s390x: virtio-mem support

 MAINTAINERS                    |   4 +
 hw/s390x/Kconfig               |   1 +
 hw/s390x/meson.build           |   4 +-
 hw/s390x/s390-hypercall.c      |  77 +++++++++++
 hw/s390x/s390-hypercall.h      |  25 ++++
 hw/s390x/s390-skeys.c          |   4 +-
 hw/s390x/s390-stattrib-kvm.c   |  63 +++++----
 hw/s390x/s390-virtio-ccw.c     | 143 +++++++++++++--------
 hw/s390x/s390-virtio-hcall.c   |  41 ------
 hw/s390x/s390-virtio-hcall.h   |  25 ----
 hw/s390x/sclp.c                |  17 +--
 hw/s390x/virtio-ccw-md.c       | 153 ++++++++++++++++++++++
 hw/s390x/virtio-ccw-md.h       |  44 +++++++
 hw/s390x/virtio-ccw-mem.c      | 226 +++++++++++++++++++++++++++++++++
 hw/s390x/virtio-ccw-mem.h      |  34 +++++
 hw/virtio/Kconfig              |   1 +
 hw/virtio/virtio-mem.c         |   4 +-
 target/s390x/cpu-sysemu.c      |  35 ++++-
 target/s390x/cpu.h             |   2 +
 target/s390x/kvm/kvm.c         |  12 +-
 target/s390x/kvm/pv.c          |   2 +-
 target/s390x/tcg/misc_helper.c |   6 +-
 22 files changed, 746 insertions(+), 177 deletions(-)
 create mode 100644 hw/s390x/s390-hypercall.c
 create mode 100644 hw/s390x/s390-hypercall.h
 delete mode 100644 hw/s390x/s390-virtio-hcall.c
 delete mode 100644 hw/s390x/s390-virtio-hcall.h
 create mode 100644 hw/s390x/virtio-ccw-md.c
 create mode 100644 hw/s390x/virtio-ccw-md.h
 create mode 100644 hw/s390x/virtio-ccw-mem.c
 create mode 100644 hw/s390x/virtio-ccw-mem.h

-- 
2.46.0