qemu/hw/s390x/meson.build
David Hildenbrand aa910c20ec s390x: virtio-mem support
Let's add our virtio-mem-ccw proxy device and wire it up. We should
be supporting everything (e.g., device unplug, "dynamic-memslots") that
we already support for the virtio-pci variant.

With a Linux guest that supports virtio-mem (and has automatic memory
onlining properly configured) the following example will work:

1. Start a VM with 4G initial memory and a virtio-mem device with a maximum
   capacity of 16GB:

   qemu/build/qemu-system-s390x \
    --enable-kvm \
    -m 4G,maxmem=20G \
    -nographic \
    -smp 8 \
    -hda Fedora-Server-KVM-40-1.14.s390x.qcow2 \
    -chardev socket,id=monitor,path=/var/tmp/monitor,server,nowait \
    -mon chardev=monitor,mode=readline \
    -object memory-backend-ram,id=mem0,size=16G,reserve=off \
    -device virtio-mem-ccw,id=vmem0,memdev=mem0,dynamic-memslots=on

2. Query the current size of virtio-mem device:

    (qemu) info memory-devices
    Memory device [virtio-mem]: "vmem0"
      memaddr: 0x100000000
      node: 0
      requested-size: 0
      size: 0
      max-size: 17179869184
      block-size: 1048576
      memdev: /objects/mem0

3. Request to grow it to 8GB (hotplug 8GB):

    (qemu) qom-set vmem0 requested-size 8G
    (qemu) info memory-devices
    Memory device [virtio-mem]: "vmem0"
      memaddr: 0x100000000
      node: 0
      requested-size: 8589934592
      size: 8589934592
      max-size: 17179869184
      block-size: 1048576
      memdev: /objects/mem0

4. Request to grow to 16GB (hotplug another 8GB):

    (qemu) qom-set vmem0 requested-size 16G
    (qemu) info memory-devices
    Memory device [virtio-mem]: "vmem0"
      memaddr: 0x100000000
      node: 0
      requested-size: 17179869184
      size: 17179869184
      max-size: 17179869184
      block-size: 1048576
      memdev: /objects/mem0

5. Try to hotunplug all memory again, shrinking to 0GB:

    (qemu) qom-set vmem0 requested-size 0G
    (qemu) info memory-devices
    Memory device [virtio-mem]: "vmem0"
      memaddr: 0x100000000
      node: 0
      requested-size: 0
      size: 0
      max-size: 17179869184
      block-size: 1048576
      memdev: /objects/mem0

6. If it worked, unplug the device

    (qemu) device_del vmem0
    (qemu) info memory-devices
    (qemu) object_del mem0

7. Hotplug a new device with a smaller capacity and directly size it to 1GB

    (qemu) object_add memory-backend-ram,id=mem0,size=8G,reserve=off
    (qemu) device_add virtio-mem-ccw,id=vmem0,memdev=mem0,\
                      dynamic-memslots=on,requested-size=1G
    (qemu) info memory-devices
    Memory device [virtio-mem]: "vmem0"
      memaddr: 0x100000000
      node: 0
      requested-size: 1073741824
      size: 1073741824
      max-size: 8589934592
      block-size: 1048576
      memdev: /objects/mem0

Trying to use a virtio-mem device backed by hugetlb into a !hugetlb VM
correctly results in the error:
   ... Memory device uses a bigger page size than initial memory

Note that the virtio-mem driver in Linux will supports 1 MiB (pageblock)
granularity.

Message-ID: <20241219144115.2820241-15-david@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
2024-12-21 20:15:06 +01:00

66 lines
2.4 KiB
Meson

s390x_ss = ss.source_set()
s390x_ss.add(files(
'ap-bridge.c',
'ap-device.c',
'ccw-device.c',
'css-bridge.c',
'css.c',
'event-facility.c',
'ipl.c',
's390-ccw.c',
's390-pci-bus.c',
's390-pci-inst.c',
's390-skeys.c',
's390-stattrib.c',
'sclp.c',
'sclpcpu.c',
'sclpquiesce.c',
'tod.c',
))
s390x_ss.add(when: 'CONFIG_KVM', if_true: files(
'tod-kvm.c',
's390-skeys-kvm.c',
's390-stattrib-kvm.c',
's390-pci-kvm.c',
'cpu-topology.c',
))
s390x_ss.add(when: 'CONFIG_TCG', if_true: files(
'tod-tcg.c',
))
s390x_ss.add(when: 'CONFIG_S390_CCW_VIRTIO', if_true: files(
's390-virtio-ccw.c',
's390-hypercall.c',
))
s390x_ss.add(when: 'CONFIG_TERMINAL3270', if_true: files('3270-ccw.c'))
s390x_ss.add(when: 'CONFIG_VFIO', if_true: files('s390-pci-vfio.c'))
virtio_ss = ss.source_set()
virtio_ss.add(files('virtio-ccw.c'))
virtio_ss.add(when: 'CONFIG_VIRTIO_BALLOON', if_true: files('virtio-ccw-balloon.c'))
virtio_ss.add(when: 'CONFIG_VIRTIO_BLK', if_true: files('virtio-ccw-blk.c'))
virtio_ss.add(when: 'CONFIG_VIRTIO_CRYPTO', if_true: files('virtio-ccw-crypto.c'))
virtio_ss.add(when: 'CONFIG_VIRTIO_INPUT', if_true: files('virtio-ccw-input.c'))
virtio_ss.add(when: 'CONFIG_VIRTIO_NET', if_true: files('virtio-ccw-net.c'))
virtio_ss.add(when: 'CONFIG_VIRTIO_RNG', if_true: files('virtio-ccw-rng.c'))
virtio_ss.add(when: 'CONFIG_VIRTIO_SCSI', if_true: files('virtio-ccw-scsi.c'))
virtio_ss.add(when: 'CONFIG_VIRTIO_SERIAL', if_true: files('virtio-ccw-serial.c'))
if have_virtfs
virtio_ss.add(when: 'CONFIG_VIRTIO_9P', if_true: files('virtio-ccw-9p.c'))
endif
virtio_ss.add(when: 'CONFIG_VHOST_SCSI', if_true: files('vhost-scsi-ccw.c'))
virtio_ss.add(when: 'CONFIG_VHOST_VSOCK', if_true: files('vhost-vsock-ccw.c'))
virtio_ss.add(when: 'CONFIG_VHOST_USER_FS', if_true: files('vhost-user-fs-ccw.c'))
virtio_ss.add(when: 'CONFIG_VIRTIO_MD', if_true: files('virtio-ccw-md.c'))
virtio_ss.add(when: 'CONFIG_VIRTIO_MEM', if_true: files('virtio-ccw-mem.c'))
s390x_ss.add_all(when: 'CONFIG_VIRTIO_CCW', if_true: virtio_ss)
s390x_ss.add(when: 'CONFIG_VIRTIO_MD', if_false: files('virtio-ccw-md-stubs.c'))
hw_arch += {'s390x': s390x_ss}
hw_s390x_modules = {}
virtio_gpu_ccw_ss = ss.source_set()
virtio_gpu_ccw_ss.add(when: ['CONFIG_VIRTIO_GPU', 'CONFIG_VIRTIO_CCW'],
if_true: [files('virtio-ccw-gpu.c'), pixman])
hw_s390x_modules += {'virtio-gpu-ccw': virtio_gpu_ccw_ss}
modules += {'hw-s390x': hw_s390x_modules}