On Fri, 5 Jun 2026 18:46:06 +0800 fanhuang <[email protected]> wrote:
> Introduce a TYPE_MEMORY_DEVICE subclass `sp-mem` for boot-time > SOFT_RESERVED memory exposed to the guest with a per-device NUMA > proximity domain. > > The device targets accelerator memory (HBM and similar) that the > firmware hands to the guest OS as SOFT_RESERVED memory, so a driver > in the guest -- rather than the kernel's general allocator -- owns > the range. > > Usage: > > -object memory-backend-ram,id=spm0,size=$SIZE > -numa node,nodeid=$N > -device sp-mem,id=dev0,memdev=spm0,node=$N[,addr=$GPA] > > The device is boot-time only (no hotplug). > > Signed-off-by: FangSheng Huang <[email protected]> > --- > qapi/machine.json | 43 ++++++++++++- > include/hw/mem/sp-mem.h | 35 +++++++++++ > hw/mem/sp-mem.c | 130 ++++++++++++++++++++++++++++++++++++++++ > hw/mem/Kconfig | 4 ++ > hw/mem/meson.build | 1 + > 5 files changed, 211 insertions(+), 2 deletions(-) > create mode 100644 include/hw/mem/sp-mem.h > create mode 100644 hw/mem/sp-mem.c > > diff --git a/qapi/machine.json b/qapi/machine.json > index 685e4e29b8..41cc3a188a 100644 > --- a/qapi/machine.json > +++ b/qapi/machine.json > @@ -1413,6 +1413,32 @@ > } > } > > +## > +# @SpMemDeviceInfo: > +# > +# sp-mem device state information > +# > +# @id: device's ID > +# > +# @memaddr: physical address in memory, where device is mapped > +# > +# @size: size of memory that the device provides > +# > +# @node: NUMA proximity domain to which the device is assigned > +# > +# @memdev: memory backend linked with device > +# > +# Since: 11.1 > +## > +{ 'struct': 'SpMemDeviceInfo', > + 'data': { '*id': 'str', > + 'memaddr': 'size', why not 'addr', like DIMM? > + 'size': 'size', > + 'node': 'int', > + 'memdev': 'str' > + } > +} > + > ## > # @MemoryDeviceInfoKind: > # > @@ -1426,11 +1452,13 @@ > # > # @hv-balloon: since 8.2. > # > +# @sp-mem: since 11.1. > +# > # Since: 2.1 > ## > { 'enum': 'MemoryDeviceInfoKind', > 'data': [ 'dimm', 'nvdimm', 'virtio-pmem', 'virtio-mem', 'sgx-epc', > - 'hv-balloon' ] } > + 'hv-balloon', 'sp-mem' ] } > > ## > # @PCDIMMDeviceInfoWrapper: > @@ -1482,6 +1510,16 @@ > { 'struct': 'HvBalloonDeviceInfoWrapper', > 'data': { 'data': 'HvBalloonDeviceInfo' } } > > +## > +# @SpMemDeviceInfoWrapper: > +# > +# @data: sp-mem device state information > +# > +# Since: 11.1 > +## > +{ 'struct': 'SpMemDeviceInfoWrapper', > + 'data': { 'data': 'SpMemDeviceInfo' } } > + > ## > # @MemoryDeviceInfo: > # > @@ -1499,7 +1537,8 @@ > 'virtio-pmem': 'VirtioPMEMDeviceInfoWrapper', > 'virtio-mem': 'VirtioMEMDeviceInfoWrapper', > 'sgx-epc': 'SgxEPCDeviceInfoWrapper', > - 'hv-balloon': 'HvBalloonDeviceInfoWrapper' > + 'hv-balloon': 'HvBalloonDeviceInfoWrapper', > + 'sp-mem': 'SpMemDeviceInfoWrapper' > } > } > > diff --git a/include/hw/mem/sp-mem.h b/include/hw/mem/sp-mem.h > new file mode 100644 > index 0000000000..5c0b6ec4f8 > --- /dev/null > +++ b/include/hw/mem/sp-mem.h > @@ -0,0 +1,35 @@ > +/* > + * Specific Purpose Memory (SPM) device > + * > + * TYPE_MEMORY_DEVICE subclass for boot-time-only memory exposed to the > + * guest as an E820 SOFT_RESERVED range with a SRAT memory-affinity entry. > + * > + * Copyright (c) 2026 Advanced Micro Devices, Inc. > + * > + * Authors: > + * FangSheng Huang <[email protected]> > + * > + * SPDX-License-Identifier: GPL-2.0-or-later > + */ > + > +#ifndef QEMU_SP_MEM_H > +#define QEMU_SP_MEM_H > + > +#include "hw/mem/memory-device.h" > +#include "hw/core/qdev.h" > +#include "qom/object.h" > +#include "system/hostmem.h" > + > +#define TYPE_SP_MEM "sp-mem" > + > +OBJECT_DECLARE_SIMPLE_TYPE(SpMemDevice, SP_MEM) > + > +struct SpMemDevice { > + DeviceState parent_obj; > + > + HostMemoryBackend *hostmem; > + uint32_t node; > + uint64_t addr; > +}; > + > +#endif /* QEMU_SP_MEM_H */ > diff --git a/hw/mem/sp-mem.c b/hw/mem/sp-mem.c > new file mode 100644 > index 0000000000..f6ba9a6d7c > --- /dev/null > +++ b/hw/mem/sp-mem.c > @@ -0,0 +1,130 @@ > +/* > + * Specific Purpose Memory (SPM) device > + * > + * Copyright (c) 2026 Advanced Micro Devices, Inc. > + * > + * Authors: > + * FangSheng Huang <[email protected]> > + * > + * SPDX-License-Identifier: GPL-2.0-or-later > + */ > + > +#include "qemu/osdep.h" > +#include "qemu/module.h" > +#include "qapi/error.h" > +#include "hw/core/qdev-properties.h" > +#include "hw/core/qdev.h" > +#include "hw/mem/sp-mem.h" > +#include "hw/mem/memory-device.h" > +#include "migration/vmstate.h" > +#include "system/hostmem.h" > + > +#define SP_MEM_MEMDEV_PROP "memdev" > +#define SP_MEM_NODE_PROP "node" > +#define SP_MEM_ADDR_PROP "addr" > + > +static const Property sp_mem_properties[] = { > + DEFINE_PROP_LINK(SP_MEM_MEMDEV_PROP, SpMemDevice, hostmem, > + TYPE_MEMORY_BACKEND, HostMemoryBackend *), > + DEFINE_PROP_UINT32(SP_MEM_NODE_PROP, SpMemDevice, node, 0), > + DEFINE_PROP_UINT64(SP_MEM_ADDR_PROP, SpMemDevice, addr, 0), > +}; > + > +static uint64_t sp_mem_get_addr(const MemoryDeviceState *md) > +{ > + return SP_MEM(md)->addr; device cast + deref, should be separate. or even better look at pc_dimm_md_get_addr() > +} > + > +static void sp_mem_set_addr(MemoryDeviceState *md, uint64_t addr, > + Error **errp) > +{ > + SP_MEM(md)->addr = addr; > +} ditto > + > +static MemoryRegion *sp_mem_get_memory_region(MemoryDeviceState *md, > + Error **errp) > +{ > + SpMemDevice *spm = SP_MEM(md); > + > + if (!spm->hostmem) { > + error_setg(errp, "'memdev' property must be set"); > + return NULL; > + } > + return host_memory_backend_get_memory(spm->hostmem); > +} > + > +static uint64_t sp_mem_get_plugged_size(const MemoryDeviceState *md, > + Error **errp) > +{ > + SpMemDevice *spm = SP_MEM(md); > + return spm->hostmem ? > + memory_region_size(host_memory_backend_get_memory(spm->hostmem)) : 0; > +} > + > +static void sp_mem_fill_device_info(const MemoryDeviceState *md, > + MemoryDeviceInfo *info) > +{ > + SpMemDeviceInfo *di = g_new0(SpMemDeviceInfo, 1); > + SpMemDevice *spm = SP_MEM(md); > + DeviceState *dev = DEVICE(md); > + > + di->id = dev->id ? g_strdup(dev->id) : NULL; > + di->memaddr = spm->addr; > + di->size = spm->hostmem ? memory_region_size( > + host_memory_backend_get_memory(spm->hostmem)) : 0; why conditional? > + di->node = spm->node; > + di->memdev = spm->hostmem ? > + object_get_canonical_path(OBJECT(spm->hostmem)) : NULL; ditto > + > + info->u.sp_mem.data = di; > + info->type = MEMORY_DEVICE_INFO_KIND_SP_MEM; > +} > + > +static void sp_mem_realize(DeviceState *dev, Error **errp) > +{ > + SpMemDevice *spm = SP_MEM(dev); > + > + if (!spm->hostmem) { > + error_setg(errp, "'%s' property is required", SP_MEM_MEMDEV_PROP); > + return; > + } > +} > + > +/* boot-time only; no plug/unplug state to migrate */ > +static const VMStateDescription vmstate_sp_mem = { > + .name = TYPE_SP_MEM, > + .unmigratable = 1, > +}; > + > +static void sp_mem_class_init(ObjectClass *oc, const void *data) > +{ > + DeviceClass *dc = DEVICE_CLASS(oc); > + MemoryDeviceClass *mdc = MEMORY_DEVICE_CLASS(oc); > + > + dc->desc = "SPM (Specific Purpose Memory) device"; > + dc->hotpluggable = false; > + dc->realize = sp_mem_realize; > + dc->vmsd = &vmstate_sp_mem; > + device_class_set_props(dc, sp_mem_properties); > + > + mdc->get_addr = sp_mem_get_addr; > + mdc->set_addr = sp_mem_set_addr; > + mdc->get_memory_region = sp_mem_get_memory_region; > + mdc->get_plugged_size = sp_mem_get_plugged_size; ^^^^ wouldn't memory_device_get_region_size() do here? > + mdc->fill_device_info = sp_mem_fill_device_info; > +} > + > +static const TypeInfo sp_mem_types[] = { > + { > + .name = TYPE_SP_MEM, > + .parent = TYPE_DEVICE, > + .class_init = sp_mem_class_init, > + .instance_size = sizeof(SpMemDevice), > + .interfaces = (InterfaceInfo[]) { > + { TYPE_MEMORY_DEVICE }, > + { } > + }, > + }, > +}; > + > +DEFINE_TYPES(sp_mem_types) > diff --git a/hw/mem/Kconfig b/hw/mem/Kconfig > index 73c5ae8ad9..39ddb36710 100644 > --- a/hw/mem/Kconfig > +++ b/hw/mem/Kconfig > @@ -16,3 +16,7 @@ config CXL_MEM_DEVICE > bool > default y if CXL > select MEM_DEVICE > + > +config SP_MEM > + bool > + select MEM_DEVICE > diff --git a/hw/mem/meson.build b/hw/mem/meson.build > index 8c2beeb7d4..f410d75475 100644 > --- a/hw/mem/meson.build > +++ b/hw/mem/meson.build > @@ -4,6 +4,7 @@ mem_ss.add(when: 'CONFIG_DIMM', if_true: files('pc-dimm.c')) > mem_ss.add(when: 'CONFIG_NPCM7XX', if_true: files('npcm7xx_mc.c')) > mem_ss.add(when: 'CONFIG_NVDIMM', if_true: files('nvdimm.c')) > mem_ss.add(when: 'CONFIG_CXL_MEM_DEVICE', if_true: files('cxl_type3.c')) > +mem_ss.add(when: 'CONFIG_SP_MEM', if_true: files('sp-mem.c')) > stub_ss.add(files('cxl_type3_stubs.c')) > > stub_ss.add(files('memory-device-stubs.c'))
