Let's implement support for abstract virtio based memory devices, using
the virtio-pci implementation as an orientation. Wire them up in the
machine hotplug handler, taking care of s390x page size limitations.
As we neither support virtio-mem or virtio-pmem yet, the code is
effectively unused. We'll implement support for virtio-mem based on this
next.
Note that we won't wire up the virtio-pci variant (should currently be
impossible due to lack of support for MSI-X), but we'll add a safety net
to reject plugging them in the pre-plug handler.
Message-ID: <20241219144115.2820241-14-david@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
MAINTAINERS | 3 +
hw/s390x/meson.build | 3 +
hw/s390x/s390-virtio-ccw.c | 47 +++++++++-
hw/s390x/virtio-ccw-md-stubs.c | 24 ++++++
hw/s390x/virtio-ccw-md.c | 153 +++++++++++++++++++++++++++++++++
hw/s390x/virtio-ccw-md.h | 44 ++++++++++
hw/virtio/Kconfig | 1 +
7 files changed, 274 insertions(+), 1 deletion(-)
create mode 100644 hw/s390x/virtio-ccw-md-stubs.c
create mode 100644 hw/s390x/virtio-ccw-md.c
create mode 100644 hw/s390x/virtio-ccw-md.h
diff --git a/MAINTAINERS b/MAINTAINERS
index 430a0f4f8c..afb1203597 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2376,6 +2376,9 @@ F: include/hw/virtio/virtio-crypto.h
virtio based memory device
M: David Hildenbrand <david@redhat.com>
S: Supported
+F: hw/s390x/virtio-ccw-md.c
+F: hw/s390x/virtio-ccw-md.h
+F: hw/s390x/virtio-ccw-md-stubs.c
F: hw/virtio/virtio-md-pci.c
F: include/hw/virtio/virtio-md-pci.h
F: stubs/virtio-md-pci.c
diff --git a/hw/s390x/meson.build b/hw/s390x/meson.build
index e344a3bd8c..4431868408 100644
--- a/hw/s390x/meson.build
+++ b/hw/s390x/meson.build
@@ -50,8 +50,11 @@ 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'))
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 = {}
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 9f8d830798..097ec78826 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -46,6 +46,8 @@
#include "qapi/visitor.h"
#include "hw/s390x/cpu-topology.h"
#include "kvm/kvm_s390x.h"
+#include "hw/virtio/virtio-md-pci.h"
+#include "hw/s390x/virtio-ccw-md.h"
#include CONFIG_DEVICES
static Error *pv_mig_blocker;
@@ -546,11 +548,39 @@ static void s390_machine_reset(MachineState *machine, ResetType type)
s390_ipl_clear_reset_request();
}
+static void s390_machine_device_pre_plug(HotplugHandler *hotplug_dev,
+ DeviceState *dev, Error **errp)
+{
+ if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_MD_CCW)) {
+ virtio_ccw_md_pre_plug(VIRTIO_MD_CCW(dev), MACHINE(hotplug_dev), errp);
+ } else if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_MD_PCI)) {
+ error_setg(errp,
+ "PCI-attached virtio based memory devices not supported");
+ }
+}
+
static void s390_machine_device_plug(HotplugHandler *hotplug_dev,
DeviceState *dev, Error **errp)
{
+ S390CcwMachineState *s390ms = S390_CCW_MACHINE(hotplug_dev);
+
if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
s390_cpu_plug(hotplug_dev, dev, errp);
+ } else if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_MD_CCW)) {
+ /*
+ * At this point, the device is realized and set all memdevs mapped, so
+ * qemu_maxrampagesize() will pick up the page sizes of these memdevs
+ * as well. Before we plug the device and expose any RAM memory regions
+ * to the system, make sure we don't exceed the previously set max page
+ * size. While only relevant for KVM, there is not really any use case
+ * for this with TCG, so we'll unconditionally reject it.
+ */
+ if (qemu_maxrampagesize() != s390ms->max_pagesize) {
+ error_setg(errp, "Memory device uses a bigger page size than"
+ " initial memory");
+ return;
+ }
+ virtio_ccw_md_plug(VIRTIO_MD_CCW(dev), MACHINE(hotplug_dev), errp);
}
}
@@ -560,9 +590,20 @@ static void s390_machine_device_unplug_request(HotplugHandler *hotplug_dev,
if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
error_setg(errp, "CPU hot unplug not supported on this machine");
return;
+ } else if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_MD_CCW)) {
+ virtio_ccw_md_unplug_request(VIRTIO_MD_CCW(dev), MACHINE(hotplug_dev),
+ errp);
}
}
+static void s390_machine_device_unplug(HotplugHandler *hotplug_dev,
+ DeviceState *dev, Error **errp)
+{
+ if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_MD_CCW)) {
+ virtio_ccw_md_unplug(VIRTIO_MD_CCW(dev), MACHINE(hotplug_dev), errp);
+ }
+ }
+
static CpuInstanceProperties s390_cpu_index_to_props(MachineState *ms,
unsigned cpu_index)
{
@@ -609,7 +650,9 @@ static const CPUArchIdList *s390_possible_cpu_arch_ids(MachineState *ms)
static HotplugHandler *s390_get_hotplug_handler(MachineState *machine,
DeviceState *dev)
{
- if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
+ if (object_dynamic_cast(OBJECT(dev), TYPE_CPU) ||
+ object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_MD_CCW) ||
+ object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_MD_PCI)) {
return HOTPLUG_HANDLER(machine);
}
return NULL;
@@ -769,8 +812,10 @@ static void ccw_machine_class_init(ObjectClass *oc, void *data)
mc->possible_cpu_arch_ids = s390_possible_cpu_arch_ids;
/* it is overridden with 'host' cpu *in kvm_arch_init* */
mc->default_cpu_type = S390_CPU_TYPE_NAME("qemu");
+ hc->pre_plug = s390_machine_device_pre_plug;
hc->plug = s390_machine_device_plug;
hc->unplug_request = s390_machine_device_unplug_request;
+ hc->unplug = s390_machine_device_unplug;
nc->nmi_monitor_handler = s390_nmi;
mc->default_ram_id = "s390.ram";
mc->default_nic = "virtio-net-ccw";
diff --git a/hw/s390x/virtio-ccw-md-stubs.c b/hw/s390x/virtio-ccw-md-stubs.c
new file mode 100644
index 0000000000..e937865550
--- /dev/null
+++ b/hw/s390x/virtio-ccw-md-stubs.c
@@ -0,0 +1,24 @@
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "hw/s390x/virtio-ccw-md.h"
+
+void virtio_ccw_md_pre_plug(VirtIOMDCcw *vmd, MachineState *ms, Error **errp)
+{
+ error_setg(errp, "virtio based memory devices not supported");
+}
+
+void virtio_ccw_md_plug(VirtIOMDCcw *vmd, MachineState *ms, Error **errp)
+{
+ error_setg(errp, "virtio based memory devices not supported");
+}
+
+void virtio_ccw_md_unplug_request(VirtIOMDCcw *vmd, MachineState *ms,
+ Error **errp)
+{
+ error_setg(errp, "virtio based memory devices not supported");
+}
+
+void virtio_ccw_md_unplug(VirtIOMDCcw *vmd, MachineState *ms, Error **errp)
+{
+ error_setg(errp, "virtio based memory devices not supported");
+}
diff --git a/hw/s390x/virtio-ccw-md.c b/hw/s390x/virtio-ccw-md.c
new file mode 100644
index 0000000000..de333282df
--- /dev/null
+++ b/hw/s390x/virtio-ccw-md.c
@@ -0,0 +1,153 @@
+/*
+ * Virtio CCW support for abstract virtio based memory 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.
+ */
+
+#include "qemu/osdep.h"
+#include "hw/s390x/virtio-ccw-md.h"
+#include "hw/mem/memory-device.h"
+#include "qapi/error.h"
+#include "qemu/error-report.h"
+
+void virtio_ccw_md_pre_plug(VirtIOMDCcw *vmd, MachineState *ms, Error **errp)
+{
+ DeviceState *dev = DEVICE(vmd);
+ HotplugHandler *bus_handler = qdev_get_bus_hotplug_handler(dev);
+ MemoryDeviceState *md = MEMORY_DEVICE(vmd);
+ Error *local_err = NULL;
+
+ if (!bus_handler && dev->hotplugged) {
+ /*
+ * Without a bus hotplug handler, we cannot control the plug/unplug
+ * order. We should never reach this point when hotplugging, but
+ * better add a safety net.
+ */
+ error_setg(errp, "hotplug of virtio based memory devices not supported"
+ " on this bus.");
+ return;
+ }
+
+ /*
+ * First, see if we can plug this memory device at all. If that
+ * succeeds, branch of to the actual hotplug handler.
+ */
+ memory_device_pre_plug(md, ms, &local_err);
+ if (!local_err && bus_handler) {
+ hotplug_handler_pre_plug(bus_handler, dev, &local_err);
+ }
+ error_propagate(errp, local_err);
+}
+
+void virtio_ccw_md_plug(VirtIOMDCcw *vmd, MachineState *ms, Error **errp)
+{
+ DeviceState *dev = DEVICE(vmd);
+ HotplugHandler *bus_handler = qdev_get_bus_hotplug_handler(dev);
+ MemoryDeviceState *md = MEMORY_DEVICE(vmd);
+ Error *local_err = NULL;
+
+ /*
+ * Plug the memory device first and then branch off to the actual
+ * hotplug handler. If that one fails, we can easily undo the memory
+ * device bits.
+ */
+ memory_device_plug(md, ms);
+ if (bus_handler) {
+ hotplug_handler_plug(bus_handler, dev, &local_err);
+ if (local_err) {
+ memory_device_unplug(md, ms);
+ }
+ }
+ error_propagate(errp, local_err);
+}
+
+void virtio_ccw_md_unplug_request(VirtIOMDCcw *vmd, MachineState *ms,
+ Error **errp)
+{
+ VirtIOMDCcwClass *vmdc = VIRTIO_MD_CCW_GET_CLASS(vmd);
+ DeviceState *dev = DEVICE(vmd);
+ HotplugHandler *bus_handler = qdev_get_bus_hotplug_handler(dev);
+ HotplugHandlerClass *hdc;
+ Error *local_err = NULL;
+
+ if (!vmdc->unplug_request_check) {
+ error_setg(errp,
+ "this virtio based memory devices cannot be unplugged");
+ return;
+ }
+
+ if (!bus_handler) {
+ error_setg(errp, "hotunplug of virtio based memory devices not"
+ "supported on this bus");
+ return;
+ }
+
+ vmdc->unplug_request_check(vmd, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ return;
+ }
+
+ /*
+ * Forward the async request or turn it into a sync request (handling it
+ * like qdev_unplug()).
+ */
+ hdc = HOTPLUG_HANDLER_GET_CLASS(bus_handler);
+ if (hdc->unplug_request) {
+ hotplug_handler_unplug_request(bus_handler, dev, &local_err);
+ } else {
+ virtio_ccw_md_unplug(vmd, ms, &local_err);
+ if (!local_err) {
+ object_unparent(OBJECT(dev));
+ }
+ }
+}
+
+void virtio_ccw_md_unplug(VirtIOMDCcw *vmd, MachineState *ms, Error **errp)
+{
+ DeviceState *dev = DEVICE(vmd);
+ HotplugHandler *bus_handler = qdev_get_bus_hotplug_handler(dev);
+ MemoryDeviceState *md = MEMORY_DEVICE(vmd);
+ Error *local_err = NULL;
+
+ /* Unplug the memory device while it is still realized. */
+ memory_device_unplug(md, ms);
+
+ if (bus_handler) {
+ hotplug_handler_unplug(bus_handler, dev, &local_err);
+ if (local_err) {
+ /* Not expected to fail ... but still try to recover. */
+ memory_device_plug(md, ms);
+ error_propagate(errp, local_err);
+ return;
+ }
+ } else {
+ /* Very unexpected, but let's just try to do the right thing. */
+ warn_report("Unexpected unplug of virtio based memory device");
+ qdev_unrealize(dev);
+ }
+}
+
+static const TypeInfo virtio_ccw_md_info = {
+ .name = TYPE_VIRTIO_MD_CCW,
+ .parent = TYPE_VIRTIO_CCW_DEVICE,
+ .instance_size = sizeof(VirtIOMDCcw),
+ .class_size = sizeof(VirtIOMDCcwClass),
+ .abstract = true,
+ .interfaces = (InterfaceInfo[]) {
+ { TYPE_MEMORY_DEVICE },
+ { }
+ },
+};
+
+static void virtio_ccw_md_register(void)
+{
+ type_register_static(&virtio_ccw_md_info);
+}
+type_init(virtio_ccw_md_register)
diff --git a/hw/s390x/virtio-ccw-md.h b/hw/s390x/virtio-ccw-md.h
new file mode 100644
index 0000000000..39ba864c92
--- /dev/null
+++ b/hw/s390x/virtio-ccw-md.h
@@ -0,0 +1,44 @@
+/*
+ * Virtio CCW support for abstract virtio based memory 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_MD_H
+#define HW_S390X_VIRTIO_CCW_MD_H
+
+#include "virtio-ccw.h"
+#include "qom/object.h"
+
+/*
+ * virtio-md-ccw: This extends VirtioCcwDevice.
+ */
+#define TYPE_VIRTIO_MD_CCW "virtio-md-ccw"
+
+OBJECT_DECLARE_TYPE(VirtIOMDCcw, VirtIOMDCcwClass, VIRTIO_MD_CCW)
+
+struct VirtIOMDCcwClass {
+ /* private */
+ VirtIOCCWDeviceClass parent;
+
+ /* public */
+ void (*unplug_request_check)(VirtIOMDCcw *vmd, Error **errp);
+};
+
+struct VirtIOMDCcw {
+ VirtioCcwDevice parent_obj;
+};
+
+void virtio_ccw_md_pre_plug(VirtIOMDCcw *vmd, MachineState *ms, Error **errp);
+void virtio_ccw_md_plug(VirtIOMDCcw *vmd, MachineState *ms, Error **errp);
+void virtio_ccw_md_unplug_request(VirtIOMDCcw *vmd, MachineState *ms,
+ Error **errp);
+void virtio_ccw_md_unplug(VirtIOMDCcw *vmd, MachineState *ms, Error **errp);
+
+#endif /* HW_S390X_VIRTIO_CCW_MD_H */
diff --git a/hw/virtio/Kconfig b/hw/virtio/Kconfig
index 70c77e183d..7648a2d68d 100644
--- a/hw/virtio/Kconfig
+++ b/hw/virtio/Kconfig
@@ -29,6 +29,7 @@ config VIRTIO_MMIO
config VIRTIO_CCW
bool
select VIRTIO
+ select VIRTIO_MD_SUPPORTED
config VIRTIO_BALLOON
bool
--
2.47.1© 2016 - 2024 Red Hat, Inc.