Browse Source
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>
pull/318/head
6 changed files with 267 additions and 1 deletions
@ -0,0 +1,226 @@ |
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/*
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* virtio-mem CCW implementation |
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* |
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* Copyright (C) 2024 Red Hat, Inc. |
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* |
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* Authors: |
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* David Hildenbrand <david@redhat.com> |
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* |
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* This work is licensed under the terms of the GNU GPL, version 2. |
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* See the COPYING file in the top-level directory. |
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*/ |
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|
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#include "qemu/osdep.h" |
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#include "hw/qdev-properties.h" |
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#include "qapi/error.h" |
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#include "qemu/module.h" |
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#include "virtio-ccw-mem.h" |
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#include "hw/mem/memory-device.h" |
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#include "qapi/qapi-events-machine.h" |
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#include "qapi/qapi-events-misc.h" |
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|
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static void virtio_ccw_mem_realize(VirtioCcwDevice *ccw_dev, Error **errp) |
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{ |
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VirtIOMEMCcw *dev = VIRTIO_MEM_CCW(ccw_dev); |
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DeviceState *vdev = DEVICE(&dev->vdev); |
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|
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qdev_realize(vdev, BUS(&ccw_dev->bus), errp); |
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} |
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static void virtio_ccw_mem_set_addr(MemoryDeviceState *md, uint64_t addr, |
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Error **errp) |
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{ |
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object_property_set_uint(OBJECT(md), VIRTIO_MEM_ADDR_PROP, addr, errp); |
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} |
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|
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static uint64_t virtio_ccw_mem_get_addr(const MemoryDeviceState *md) |
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{ |
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return object_property_get_uint(OBJECT(md), VIRTIO_MEM_ADDR_PROP, |
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&error_abort); |
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} |
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|
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static MemoryRegion *virtio_ccw_mem_get_memory_region(MemoryDeviceState *md, |
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Error **errp) |
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{ |
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VirtIOMEMCcw *dev = VIRTIO_MEM_CCW(md); |
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VirtIOMEM *vmem = &dev->vdev; |
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VirtIOMEMClass *vmc = VIRTIO_MEM_GET_CLASS(vmem); |
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return vmc->get_memory_region(vmem, errp); |
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} |
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static void virtio_ccw_mem_decide_memslots(MemoryDeviceState *md, |
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unsigned int limit) |
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{ |
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VirtIOMEMCcw *dev = VIRTIO_MEM_CCW(md); |
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VirtIOMEM *vmem = VIRTIO_MEM(&dev->vdev); |
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VirtIOMEMClass *vmc = VIRTIO_MEM_GET_CLASS(vmem); |
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vmc->decide_memslots(vmem, limit); |
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} |
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static unsigned int virtio_ccw_mem_get_memslots(MemoryDeviceState *md) |
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{ |
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VirtIOMEMCcw *dev = VIRTIO_MEM_CCW(md); |
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VirtIOMEM *vmem = VIRTIO_MEM(&dev->vdev); |
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VirtIOMEMClass *vmc = VIRTIO_MEM_GET_CLASS(vmem); |
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return vmc->get_memslots(vmem); |
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} |
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static uint64_t virtio_ccw_mem_get_plugged_size(const MemoryDeviceState *md, |
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Error **errp) |
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{ |
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return object_property_get_uint(OBJECT(md), VIRTIO_MEM_SIZE_PROP, |
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errp); |
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} |
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|
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static void virtio_ccw_mem_fill_device_info(const MemoryDeviceState *md, |
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MemoryDeviceInfo *info) |
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{ |
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VirtioMEMDeviceInfo *vi = g_new0(VirtioMEMDeviceInfo, 1); |
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VirtIOMEMCcw *dev = VIRTIO_MEM_CCW(md); |
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VirtIOMEM *vmem = &dev->vdev; |
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VirtIOMEMClass *vpc = VIRTIO_MEM_GET_CLASS(vmem); |
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DeviceState *vdev = DEVICE(md); |
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if (vdev->id) { |
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vi->id = g_strdup(vdev->id); |
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} |
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/* let the real device handle everything else */ |
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vpc->fill_device_info(vmem, vi); |
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info->u.virtio_mem.data = vi; |
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info->type = MEMORY_DEVICE_INFO_KIND_VIRTIO_MEM; |
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} |
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static uint64_t virtio_ccw_mem_get_min_alignment(const MemoryDeviceState *md) |
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{ |
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return object_property_get_uint(OBJECT(md), VIRTIO_MEM_BLOCK_SIZE_PROP, |
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&error_abort); |
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} |
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static void virtio_ccw_mem_size_change_notify(Notifier *notifier, void *data) |
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{ |
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VirtIOMEMCcw *dev = container_of(notifier, VirtIOMEMCcw, |
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size_change_notifier); |
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DeviceState *vdev = DEVICE(dev); |
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char *qom_path = object_get_canonical_path(OBJECT(dev)); |
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const uint64_t * const size_p = data; |
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qapi_event_send_memory_device_size_change(vdev->id, *size_p, qom_path); |
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g_free(qom_path); |
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} |
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static void virtio_ccw_mem_unplug_request_check(VirtIOMDCcw *vmd, Error **errp) |
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{ |
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VirtIOMEMCcw *dev = VIRTIO_MEM_CCW(vmd); |
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VirtIOMEM *vmem = &dev->vdev; |
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VirtIOMEMClass *vpc = VIRTIO_MEM_GET_CLASS(vmem); |
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vpc->unplug_request_check(vmem, errp); |
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} |
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static void virtio_ccw_mem_get_requested_size(Object *obj, Visitor *v, |
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const char *name, void *opaque, |
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Error **errp) |
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{ |
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VirtIOMEMCcw *dev = VIRTIO_MEM_CCW(obj); |
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object_property_get(OBJECT(&dev->vdev), name, v, errp); |
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} |
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static void virtio_ccw_mem_set_requested_size(Object *obj, Visitor *v, |
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const char *name, void *opaque, |
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Error **errp) |
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{ |
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VirtIOMEMCcw *dev = VIRTIO_MEM_CCW(obj); |
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DeviceState *vdev = DEVICE(obj); |
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/*
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* If we passed virtio_ccw_mem_unplug_request_check(), making sure that |
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* the requested size is 0, don't allow modifying the requested size |
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* anymore, otherwise the VM might end up hotplugging memory before |
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* handling the unplug request. |
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*/ |
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if (vdev->pending_deleted_event) { |
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error_setg(errp, "'%s' cannot be changed if the device is in the" |
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" process of unplug", name); |
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return; |
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} |
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object_property_set(OBJECT(&dev->vdev), name, v, errp); |
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} |
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static Property virtio_ccw_mem_properties[] = { |
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DEFINE_PROP_BIT("ioeventfd", VirtioCcwDevice, flags, |
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VIRTIO_CCW_FLAG_USE_IOEVENTFD_BIT, true), |
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DEFINE_PROP_UINT32("max_revision", VirtioCcwDevice, max_rev, |
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VIRTIO_CCW_MAX_REV), |
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DEFINE_PROP_END_OF_LIST(), |
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}; |
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static void virtio_ccw_mem_class_init(ObjectClass *klass, void *data) |
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{ |
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DeviceClass *dc = DEVICE_CLASS(klass); |
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VirtIOCCWDeviceClass *k = VIRTIO_CCW_DEVICE_CLASS(klass); |
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MemoryDeviceClass *mdc = MEMORY_DEVICE_CLASS(klass); |
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VirtIOMDCcwClass *vmdc = VIRTIO_MD_CCW_CLASS(klass); |
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k->realize = virtio_ccw_mem_realize; |
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set_bit(DEVICE_CATEGORY_MISC, dc->categories); |
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device_class_set_props(dc, virtio_ccw_mem_properties); |
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mdc->get_addr = virtio_ccw_mem_get_addr; |
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mdc->set_addr = virtio_ccw_mem_set_addr; |
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mdc->get_plugged_size = virtio_ccw_mem_get_plugged_size; |
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mdc->get_memory_region = virtio_ccw_mem_get_memory_region; |
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mdc->decide_memslots = virtio_ccw_mem_decide_memslots; |
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mdc->get_memslots = virtio_ccw_mem_get_memslots; |
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mdc->fill_device_info = virtio_ccw_mem_fill_device_info; |
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mdc->get_min_alignment = virtio_ccw_mem_get_min_alignment; |
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vmdc->unplug_request_check = virtio_ccw_mem_unplug_request_check; |
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} |
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static void virtio_ccw_mem_instance_init(Object *obj) |
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{ |
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VirtIOMEMCcw *dev = VIRTIO_MEM_CCW(obj); |
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VirtIOMEMClass *vmc; |
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VirtIOMEM *vmem; |
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virtio_instance_init_common(obj, &dev->vdev, sizeof(dev->vdev), |
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TYPE_VIRTIO_MEM); |
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dev->size_change_notifier.notify = virtio_ccw_mem_size_change_notify; |
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vmem = &dev->vdev; |
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vmc = VIRTIO_MEM_GET_CLASS(vmem); |
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/*
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* We never remove the notifier again, as we expect both devices to |
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* disappear at the same time. |
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*/ |
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vmc->add_size_change_notifier(vmem, &dev->size_change_notifier); |
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object_property_add_alias(obj, VIRTIO_MEM_BLOCK_SIZE_PROP, |
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OBJECT(&dev->vdev), VIRTIO_MEM_BLOCK_SIZE_PROP); |
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object_property_add_alias(obj, VIRTIO_MEM_SIZE_PROP, OBJECT(&dev->vdev), |
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VIRTIO_MEM_SIZE_PROP); |
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object_property_add(obj, VIRTIO_MEM_REQUESTED_SIZE_PROP, "size", |
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virtio_ccw_mem_get_requested_size, |
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virtio_ccw_mem_set_requested_size, NULL, NULL); |
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} |
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|
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static const TypeInfo virtio_ccw_mem = { |
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.name = TYPE_VIRTIO_MEM_CCW, |
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.parent = TYPE_VIRTIO_MD_CCW, |
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.instance_size = sizeof(VirtIOMEMCcw), |
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.instance_init = virtio_ccw_mem_instance_init, |
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.class_init = virtio_ccw_mem_class_init, |
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}; |
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|
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static void virtio_ccw_mem_register_types(void) |
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{ |
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type_register_static(&virtio_ccw_mem); |
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} |
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type_init(virtio_ccw_mem_register_types) |
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@ -0,0 +1,34 @@ |
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/*
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* Virtio MEM CCW device |
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* |
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* Copyright (C) 2024 Red Hat, Inc. |
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* |
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* Authors: |
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* David Hildenbrand <david@redhat.com> |
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* |
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* This work is licensed under the terms of the GNU GPL, version 2. |
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* See the COPYING file in the top-level directory. |
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*/ |
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|
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#ifndef HW_S390X_VIRTIO_CCW_MEM_H |
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#define HW_S390X_VIRTIO_CCW_MEM_H |
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|
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#include "virtio-ccw-md.h" |
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#include "hw/virtio/virtio-mem.h" |
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#include "qom/object.h" |
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typedef struct VirtIOMEMCcw VirtIOMEMCcw; |
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/*
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* virtio-mem-ccw: This extends VirtIOMDCcw |
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*/ |
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#define TYPE_VIRTIO_MEM_CCW "virtio-mem-ccw" |
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DECLARE_INSTANCE_CHECKER(VirtIOMEMCcw, VIRTIO_MEM_CCW, TYPE_VIRTIO_MEM_CCW) |
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struct VirtIOMEMCcw { |
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VirtIOMDCcw parent_obj; |
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VirtIOMEM vdev; |
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Notifier size_change_notifier; |
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}; |
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|
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#endif /* HW_S390X_VIRTIO_CCW_MEM_H */ |
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Reference in new issue