@@ -10,3 +10,4 @@ config S390_CCW_VIRTIO
select SCLPCONSOLE
select VIRTIO_CCW
select MSI_NONBROKEN
+ select VIRTIO_MEM_SUPPORTED
@@ -20,6 +20,7 @@ obj-$(CONFIG_VIRTIO_NET) += virtio-ccw-net.o
obj-$(CONFIG_VIRTIO_BLK) += virtio-ccw-blk.o
obj-$(call land,$(CONFIG_VIRTIO_9P),$(CONFIG_VIRTFS)) += virtio-ccw-9p.o
obj-$(CONFIG_VHOST_VSOCK) += vhost-vsock-ccw.o
+obj-$(CONFIG_VIRTIO_MEM) += virtio-ccw-mem.o
endif
obj-y += css-bridge.o
obj-y += ccw-device.o
@@ -45,6 +45,7 @@
#include "sysemu/sysemu.h"
#include "hw/s390x/pv.h"
#include "migration/blocker.h"
+#include "hw/mem/memory-device.h"
static Error *pv_mig_blocker;
@@ -542,11 +543,119 @@ static void s390_machine_reset(MachineState *machine)
s390_ipl_clear_reset_request();
}
+static void s390_virtio_md_pre_plug(HotplugHandler *hotplug_dev,
+ DeviceState *dev, Error **errp)
+{
+ HotplugHandler *hotplug_dev2 = qdev_get_bus_hotplug_handler(dev);
+ MemoryDeviceState *md = MEMORY_DEVICE(dev);
+ MemoryDeviceClass *mdc = MEMORY_DEVICE_GET_CLASS(md);
+ Error *local_err = NULL;
+
+ if (!hotplug_dev2 && dev->hotplugged) {
+ /*
+ * Without a bus hotplug handler, we cannot control the plug/unplug
+ * order. We should never reach this point when hotplugging, however,
+ * better add a safety net.
+ */
+ error_setg(errp, "hotplug of virtio based memory devices not supported"
+ " on this bus.");
+ return;
+ }
+
+ /*
+ * KVM does not support device memory with a bigger page size than initial
+ * memory. The new memory backend is not mapped yet, so
+ * qemu_maxrampagesize() won't consider it.
+ */
+ if (kvm_enabled()) {
+ MemoryRegion *mr = mdc->get_memory_region(md, &local_err);
+
+ if (local_err) {
+ goto out;
+ }
+ if (qemu_ram_pagesize(mr->ram_block) > qemu_maxrampagesize()) {
+ error_setg(&local_err, "Device memory has a bigger page size than"
+ " initial memory");
+ goto out;
+ }
+ }
+
+ /*
+ * 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, MACHINE(hotplug_dev), NULL, &local_err);
+ if (!local_err && hotplug_dev2) {
+ hotplug_handler_pre_plug(hotplug_dev2, dev, &local_err);
+ }
+out:
+ error_propagate(errp, local_err);
+}
+
+static void s390_virtio_md_plug(HotplugHandler *hotplug_dev,
+ DeviceState *dev, Error **errp)
+{
+ HotplugHandler *hotplug_dev2 = qdev_get_bus_hotplug_handler(dev);
+ static Error *migration_blocker;
+ bool add_blocker = !migration_blocker;
+ Error *local_err = NULL;
+
+ /*
+ * Until we support migration of storage keys and storage attributes
+ * for anything that's not initial memory, let's block migration.
+ */
+ if (add_blocker) {
+ error_setg(&migration_blocker, "storage keys/attributes not yet"
+ " migrated for memory devices");
+ migrate_add_blocker(migration_blocker, &local_err);
+ if (local_err) {
+ error_free_or_abort(&migration_blocker);
+ goto out;
+ }
+ }
+
+ /*
+ * 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(MEMORY_DEVICE(dev), MACHINE(hotplug_dev));
+ if (hotplug_dev2) {
+ hotplug_handler_plug(hotplug_dev2, dev, &local_err);
+ if (local_err) {
+ memory_device_unplug(MEMORY_DEVICE(dev), MACHINE(hotplug_dev));
+ if (add_blocker) {
+ migrate_del_blocker(migration_blocker);
+ error_free_or_abort(&migration_blocker);
+ }
+ }
+ }
+out:
+ error_propagate(errp, local_err);
+}
+
+static void s390_virtio_md_unplug_request(HotplugHandler *hotplug_dev,
+ DeviceState *dev, Error **errp)
+{
+ /* We don't support hot unplug of virtio based memory devices */
+ error_setg(errp, "virtio based memory devices cannot be unplugged.");
+}
+
+static void s390_machine_device_pre_plug(HotplugHandler *hotplug_dev,
+ DeviceState *dev, Error **errp)
+{
+ if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_MEM_CCW)) {
+ s390_virtio_md_pre_plug(hotplug_dev, dev, errp);
+ }
+}
+
static void s390_machine_device_plug(HotplugHandler *hotplug_dev,
DeviceState *dev, Error **errp)
{
if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
s390_cpu_plug(hotplug_dev, dev, errp);
+ } else if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_MEM_CCW)) {
+ s390_virtio_md_plug(hotplug_dev, dev, errp);
}
}
@@ -555,7 +664,8 @@ 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_MEM_CCW)) {
+ s390_virtio_md_unplug_request(hotplug_dev, dev, errp);
}
}
@@ -596,7 +706,8 @@ 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_MEM_CCW)) {
return HOTPLUG_HANDLER(machine);
}
return NULL;
@@ -668,6 +779,7 @@ 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;
nc->nmi_monitor_handler = s390_nmi;
@@ -53,6 +53,8 @@
*/
#if defined(TARGET_X86_64) || defined(TARGET_I386)
#define VIRTIO_MEM_USABLE_EXTENT (2 * (128 * MiB))
+#elif defined(TARGET_S390X)
+#define VIRTIO_MEM_USABLE_EXTENT (2 * (256 * MiB))
#else
#error VIRTIO_MEM_USABLE_EXTENT not defined
#endif
Let's wire up the initial, basic virtio-mem implementation in QEMU. It will have to see some important extensions (esp., resizeable allocations) before it can be considered production ready. Also, the focus on the Linux driver side is on memory hotplug, there are a lot of things optimize in the future to improve memory unplug capabilities. However, the basics are in place. Block migration for now, as we'll have to take proper care of storage keys and storage attributes. Also, make sure to not hotplug huge pages to a setup without huge pages. With a Linux guest that supports virtio-mem (and has CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE set for now), a basic example. 1. Start a VM with 2G initial memory and a virtio-mem device with a maximum capacity of 18GB (and an initial size of 300M): sudo qemu-system-s390x \ --enable-kvm \ -m 2G,maxmem=20G \ -smp 4 \ -nographic \ -chardev socket,id=monitor,path=/var/tmp/monitor,server,nowait \ -mon chardev=monitor,mode=readline \ -net nic -net user \ -hda s390x.cow2 \ -object memory-backend-ram,id=mem0,size=18G \ -device virtio-mem-ccw,id=vm0,memdev=mem0,requested-size=300M 2. Query the current size of virtio-mem device: (qemu) info memory-devices Memory device [virtio-mem]: "vm0" memaddr: 0x80000000 node: 0 requested-size: 314572800 size: 314572800 max-size: 19327352832 block-size: 1048576 memdev: /objects/mem0 3. Request to grow it to 8GB: (qemu) qom-set vm0 requested-size 8G (qemu) info memory-devices Memory device [virtio-mem]: "vm0" memaddr: 0x80000000 node: 0 requested-size: 8589934592 size: 8589934592 max-size: 19327352832 block-size: 1048576 memdev: /objects/mem0 4. Request to shrink it to 800M (might take a while, might not fully succeed, and might not be able to remove memory blocks in Linux): (qemu) qom-set vm0 requested-size 800M (qemu) info memory-devices Memory device [virtio-mem]: "vm0" memaddr: 0x80000000 node: 0 requested-size: 838860800 size: 838860800 max-size: 19327352832 block-size: 1048576 memdev: /objects/mem0 Note: Due to lack of resizeable allocations, we will go ahead and reserve a 18GB vmalloc area + size the QEMU RAM slot + KVM mamory slot 18GB. echo 1 > /proc/sys/vm/overcommit_memory might be required for now. In the future, this area will instead grow on actual demand and shrink when possible. Signed-off-by: David Hildenbrand <david@redhat.com> --- hw/s390x/Kconfig | 1 + hw/s390x/Makefile.objs | 1 + hw/s390x/s390-virtio-ccw.c | 116 ++++++++++++++++++++++++++++++++++++- hw/virtio/virtio-mem.c | 2 + 4 files changed, 118 insertions(+), 2 deletions(-)