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From: David Hildenbrand <david@redhat.com>
To: qemu-devel@nongnu.org
Cc: Halil Pasic <pasic@linux.ibm.com>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Eric Farman <farman@linux.ibm.com>, Thomas Huth <thuth@redhat.com>,
Richard Henderson <richard.henderson@linaro.org>,
"Michael S . Tsirkin" <mst@redhat.com>,
David Hildenbrand <david@redhat.com>
Subject: [PULL 15/15] s390x: virtio-mem support
Date: Wed, 18 Dec 2024 11:53:03 +0100
Message-ID: <20241218105303.1966303-16-david@redhat.com>
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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=3D20G \
-nographic \
-smp 8 \
-hda Fedora-Server-KVM-40-1.14.s390x.qcow2 \
-chardev socket,id=3Dmonitor,path=3D/var/tmp/monitor,server,nowait \
-mon chardev=3Dmonitor,mode=3Dreadline \
-object memory-backend-ram,id=3Dmem0,size=3D16G,reserve=3Doff \
-device virtio-mem-ccw,id=3Dvmem0,memdev=3Dmem0,dynamic-memslots=3Don
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=3Dmem0,size=3D8G,reserve=3Doff
(qemu) device_add virtio-mem-ccw,id=3Dvmem0,memdev=3Dmem0,\
dynamic-memslots=3Don,requested-size=3D1G
(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: <20241008105455.2302628-15-david@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
MAINTAINERS | 2 +
hw/s390x/Kconfig | 1 +
hw/s390x/meson.build | 1 +
hw/s390x/virtio-ccw-mem.c | 226 ++++++++++++++++++++++++++++++++++++++
hw/s390x/virtio-ccw-mem.h | 34 ++++++
hw/virtio/virtio-mem.c | 4 +-
6 files changed, 267 insertions(+), 1 deletion(-)
create mode 100644 hw/s390x/virtio-ccw-mem.c
create mode 100644 hw/s390x/virtio-ccw-mem.h
diff --git a/MAINTAINERS b/MAINTAINERS
index f47fce0362..898097593e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2389,6 +2389,8 @@ W: https://virtio-mem.gitlab.io/
F: hw/virtio/virtio-mem.c
F: hw/virtio/virtio-mem-pci.h
F: hw/virtio/virtio-mem-pci.c
+F: hw/s390x/virtio-ccw-mem.c
+F: hw/s390x/virtio-ccw-mem.h
F: include/hw/virtio/virtio-mem.h
=20
virtio-snd
diff --git a/hw/s390x/Kconfig b/hw/s390x/Kconfig
index 82afdaa9dc..02ea199701 100644
--- a/hw/s390x/Kconfig
+++ b/hw/s390x/Kconfig
@@ -16,3 +16,4 @@ config S390_CCW_VIRTIO
select SCLPCONSOLE
select VIRTIO_CCW
select MSI_NONBROKEN
+ select VIRTIO_MEM_SUPPORTED
diff --git a/hw/s390x/meson.build b/hw/s390x/meson.build
index 28bbe4b06c..094435cd3b 100644
--- a/hw/s390x/meson.build
+++ b/hw/s390x/meson.build
@@ -49,6 +49,7 @@ 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)
=20
s390x_ss.add(when: 'CONFIG_VIRTIO_MD', if_false: files('virtio-ccw-md-stub=
s.c'))
diff --git a/hw/s390x/virtio-ccw-mem.c b/hw/s390x/virtio-ccw-mem.c
new file mode 100644
index 0000000000..bee0d560cb
--- /dev/null
+++ b/hw/s390x/virtio-ccw-mem.c
@@ -0,0 +1,226 @@
+/*
+ * virtio-mem CCW implementation
+ *
+ * Copyright (C) 2024 Red Hat, Inc.
+ *
+ * Authors:
+ * David Hildenbrand <david@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "hw/qdev-properties.h"
+#include "qapi/error.h"
+#include "qemu/module.h"
+#include "virtio-ccw-mem.h"
+#include "hw/mem/memory-device.h"
+#include "qapi/qapi-events-machine.h"
+#include "qapi/qapi-events-misc.h"
+
+static void virtio_ccw_mem_realize(VirtioCcwDevice *ccw_dev, Error **errp)
+{
+ VirtIOMEMCcw *dev =3D VIRTIO_MEM_CCW(ccw_dev);
+ DeviceState *vdev =3D DEVICE(&dev->vdev);
+
+ qdev_realize(vdev, BUS(&ccw_dev->bus), errp);
+}
+
+static void virtio_ccw_mem_set_addr(MemoryDeviceState *md, uint64_t addr,
+ Error **errp)
+{
+ object_property_set_uint(OBJECT(md), VIRTIO_MEM_ADDR_PROP, addr, errp);
+}
+
+static uint64_t virtio_ccw_mem_get_addr(const MemoryDeviceState *md)
+{
+ return object_property_get_uint(OBJECT(md), VIRTIO_MEM_ADDR_PROP,
+ &error_abort);
+}
+
+static MemoryRegion *virtio_ccw_mem_get_memory_region(MemoryDeviceState *m=
d,
+ Error **errp)
+{
+ VirtIOMEMCcw *dev =3D VIRTIO_MEM_CCW(md);
+ VirtIOMEM *vmem =3D &dev->vdev;
+ VirtIOMEMClass *vmc =3D VIRTIO_MEM_GET_CLASS(vmem);
+
+ return vmc->get_memory_region(vmem, errp);
+}
+
+static void virtio_ccw_mem_decide_memslots(MemoryDeviceState *md,
+ unsigned int limit)
+{
+ VirtIOMEMCcw *dev =3D VIRTIO_MEM_CCW(md);
+ VirtIOMEM *vmem =3D VIRTIO_MEM(&dev->vdev);
+ VirtIOMEMClass *vmc =3D VIRTIO_MEM_GET_CLASS(vmem);
+
+ vmc->decide_memslots(vmem, limit);
+}
+
+static unsigned int virtio_ccw_mem_get_memslots(MemoryDeviceState *md)
+{
+ VirtIOMEMCcw *dev =3D VIRTIO_MEM_CCW(md);
+ VirtIOMEM *vmem =3D VIRTIO_MEM(&dev->vdev);
+ VirtIOMEMClass *vmc =3D VIRTIO_MEM_GET_CLASS(vmem);
+
+ return vmc->get_memslots(vmem);
+}
+
+static uint64_t virtio_ccw_mem_get_plugged_size(const MemoryDeviceState *m=
d,
+ Error **errp)
+{
+ return object_property_get_uint(OBJECT(md), VIRTIO_MEM_SIZE_PROP,
+ errp);
+}
+
+static void virtio_ccw_mem_fill_device_info(const MemoryDeviceState *md,
+ MemoryDeviceInfo *info)
+{
+ VirtioMEMDeviceInfo *vi =3D g_new0(VirtioMEMDeviceInfo, 1);
+ VirtIOMEMCcw *dev =3D VIRTIO_MEM_CCW(md);
+ VirtIOMEM *vmem =3D &dev->vdev;
+ VirtIOMEMClass *vpc =3D VIRTIO_MEM_GET_CLASS(vmem);
+ DeviceState *vdev =3D DEVICE(md);
+
+ if (vdev->id) {
+ vi->id =3D g_strdup(vdev->id);
+ }
+
+ /* let the real device handle everything else */
+ vpc->fill_device_info(vmem, vi);
+
+ info->u.virtio_mem.data =3D vi;
+ info->type =3D MEMORY_DEVICE_INFO_KIND_VIRTIO_MEM;
+}
+
+static uint64_t virtio_ccw_mem_get_min_alignment(const MemoryDeviceState *=
md)
+{
+ return object_property_get_uint(OBJECT(md), VIRTIO_MEM_BLOCK_SIZE_PROP,
+ &error_abort);
+}
+
+static void virtio_ccw_mem_size_change_notify(Notifier *notifier, void *da=
ta)
+{
+ VirtIOMEMCcw *dev =3D container_of(notifier, VirtIOMEMCcw,
+ size_change_notifier);
+ DeviceState *vdev =3D DEVICE(dev);
+ char *qom_path =3D object_get_canonical_path(OBJECT(dev));
+ const uint64_t * const size_p =3D data;
+
+ qapi_event_send_memory_device_size_change(vdev->id, *size_p, qom_path);
+ g_free(qom_path);
+}
+
+static void virtio_ccw_mem_unplug_request_check(VirtIOMDCcw *vmd, Error **=
errp)
+{
+ VirtIOMEMCcw *dev =3D VIRTIO_MEM_CCW(vmd);
+ VirtIOMEM *vmem =3D &dev->vdev;
+ VirtIOMEMClass *vpc =3D VIRTIO_MEM_GET_CLASS(vmem);
+
+ vpc->unplug_request_check(vmem, errp);
+}
+
+static void virtio_ccw_mem_get_requested_size(Object *obj, Visitor *v,
+ const char *name, void *opaq=
ue,
+ Error **errp)
+{
+ VirtIOMEMCcw *dev =3D VIRTIO_MEM_CCW(obj);
+
+ object_property_get(OBJECT(&dev->vdev), name, v, errp);
+}
+
+static void virtio_ccw_mem_set_requested_size(Object *obj, Visitor *v,
+ const char *name, void *opaq=
ue,
+ Error **errp)
+{
+ VirtIOMEMCcw *dev =3D VIRTIO_MEM_CCW(obj);
+ DeviceState *vdev =3D DEVICE(obj);
+
+ /*
+ * If we passed virtio_ccw_mem_unplug_request_check(), making sure that
+ * the requested size is 0, don't allow modifying the requested size
+ * anymore, otherwise the VM might end up hotplugging memory before
+ * handling the unplug request.
+ */
+ if (vdev->pending_deleted_event) {
+ error_setg(errp, "'%s' cannot be changed if the device is in the"
+ " process of unplug", name);
+ return;
+ }
+
+ object_property_set(OBJECT(&dev->vdev), name, v, errp);
+}
+
+static Property virtio_ccw_mem_properties[] =3D {
+ DEFINE_PROP_BIT("ioeventfd", VirtioCcwDevice, flags,
+ VIRTIO_CCW_FLAG_USE_IOEVENTFD_BIT, true),
+ DEFINE_PROP_UINT32("max_revision", VirtioCcwDevice, max_rev,
+ VIRTIO_CCW_MAX_REV),
+ DEFINE_PROP_END_OF_LIST(),
+};
+
+static void virtio_ccw_mem_class_init(ObjectClass *klass, void *data)
+{
+ DeviceClass *dc =3D DEVICE_CLASS(klass);
+ VirtIOCCWDeviceClass *k =3D VIRTIO_CCW_DEVICE_CLASS(klass);
+ MemoryDeviceClass *mdc =3D MEMORY_DEVICE_CLASS(klass);
+ VirtIOMDCcwClass *vmdc =3D VIRTIO_MD_CCW_CLASS(klass);
+
+ k->realize =3D virtio_ccw_mem_realize;
+ set_bit(DEVICE_CATEGORY_MISC, dc->categories);
+ device_class_set_props(dc, virtio_ccw_mem_properties);
+
+ mdc->get_addr =3D virtio_ccw_mem_get_addr;
+ mdc->set_addr =3D virtio_ccw_mem_set_addr;
+ mdc->get_plugged_size =3D virtio_ccw_mem_get_plugged_size;
+ mdc->get_memory_region =3D virtio_ccw_mem_get_memory_region;
+ mdc->decide_memslots =3D virtio_ccw_mem_decide_memslots;
+ mdc->get_memslots =3D virtio_ccw_mem_get_memslots;
+ mdc->fill_device_info =3D virtio_ccw_mem_fill_device_info;
+ mdc->get_min_alignment =3D virtio_ccw_mem_get_min_alignment;
+
+ vmdc->unplug_request_check =3D virtio_ccw_mem_unplug_request_check;
+}
+
+static void virtio_ccw_mem_instance_init(Object *obj)
+{
+ VirtIOMEMCcw *dev =3D VIRTIO_MEM_CCW(obj);
+ VirtIOMEMClass *vmc;
+ VirtIOMEM *vmem;
+
+ virtio_instance_init_common(obj, &dev->vdev, sizeof(dev->vdev),
+ TYPE_VIRTIO_MEM);
+
+ dev->size_change_notifier.notify =3D virtio_ccw_mem_size_change_notify;
+ vmem =3D &dev->vdev;
+ vmc =3D VIRTIO_MEM_GET_CLASS(vmem);
+ /*
+ * We never remove the notifier again, as we expect both devices to
+ * disappear at the same time.
+ */
+ vmc->add_size_change_notifier(vmem, &dev->size_change_notifier);
+
+ object_property_add_alias(obj, VIRTIO_MEM_BLOCK_SIZE_PROP,
+ OBJECT(&dev->vdev), VIRTIO_MEM_BLOCK_SIZE_PR=
OP);
+ object_property_add_alias(obj, VIRTIO_MEM_SIZE_PROP, OBJECT(&dev->vdev=
),
+ VIRTIO_MEM_SIZE_PROP);
+ object_property_add(obj, VIRTIO_MEM_REQUESTED_SIZE_PROP, "size",
+ virtio_ccw_mem_get_requested_size,
+ virtio_ccw_mem_set_requested_size, NULL, NULL);
+}
+
+static const TypeInfo virtio_ccw_mem =3D {
+ .name =3D TYPE_VIRTIO_MEM_CCW,
+ .parent =3D TYPE_VIRTIO_MD_CCW,
+ .instance_size =3D sizeof(VirtIOMEMCcw),
+ .instance_init =3D virtio_ccw_mem_instance_init,
+ .class_init =3D virtio_ccw_mem_class_init,
+};
+
+static void virtio_ccw_mem_register_types(void)
+{
+ type_register_static(&virtio_ccw_mem);
+}
+type_init(virtio_ccw_mem_register_types)
diff --git a/hw/s390x/virtio-ccw-mem.h b/hw/s390x/virtio-ccw-mem.h
new file mode 100644
index 0000000000..738ab2c744
--- /dev/null
+++ b/hw/s390x/virtio-ccw-mem.h
@@ -0,0 +1,34 @@
+/*
+ * Virtio MEM CCW device
+ *
+ * Copyright (C) 2024 Red Hat, Inc.
+ *
+ * Authors:
+ * David Hildenbrand <david@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
+ * See the COPYING file in the top-level directory.
+ */
+
+#ifndef HW_S390X_VIRTIO_CCW_MEM_H
+#define HW_S390X_VIRTIO_CCW_MEM_H
+
+#include "virtio-ccw-md.h"
+#include "hw/virtio/virtio-mem.h"
+#include "qom/object.h"
+
+typedef struct VirtIOMEMCcw VirtIOMEMCcw;
+
+/*
+ * virtio-mem-ccw: This extends VirtIOMDCcw
+ */
+#define TYPE_VIRTIO_MEM_CCW "virtio-mem-ccw"
+DECLARE_INSTANCE_CHECKER(VirtIOMEMCcw, VIRTIO_MEM_CCW, TYPE_VIRTIO_MEM_CCW)
+
+struct VirtIOMEMCcw {
+ VirtIOMDCcw parent_obj;
+ VirtIOMEM vdev;
+ Notifier size_change_notifier;
+};
+
+#endif /* HW_S390X_VIRTIO_CCW_MEM_H */
diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c
index a0dceaddec..48e4a58239 100644
--- a/hw/virtio/virtio-mem.c
+++ b/hw/virtio/virtio-mem.c
@@ -61,6 +61,8 @@ static uint32_t virtio_mem_default_thp_size(void)
} else if (qemu_real_host_page_size() =3D=3D 64 * KiB) {
default_thp_size =3D 512 * MiB;
}
+#elif defined(__s390x__)
+ default_thp_size =3D 1 * MiB;
#endif
=20
return default_thp_size;
@@ -168,7 +170,7 @@ static bool virtio_mem_has_shared_zeropage(RAMBlock *rb)
* necessary (as the section size can change). But it's more likely that t=
he
* section size will rather get smaller and not bigger over time.
*/
-#if defined(TARGET_X86_64) || defined(TARGET_I386)
+#if defined(TARGET_X86_64) || defined(TARGET_I386) || defined(TARGET_S390X)
#define VIRTIO_MEM_USABLE_EXTENT (2 * (128 * MiB))
#elif defined(TARGET_ARM)
#define VIRTIO_MEM_USABLE_EXTENT (2 * (512 * MiB))
--=20
2.47.1