Message ID | 20200703090252.368694-14-mst@redhat.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | [PULL,01/41] tests: disassemble-aml.sh: generate AML in readable format | expand |
On 03.07.20 11:04, Michael S. Tsirkin wrote: > From: David Hildenbrand <david@redhat.com> > > This is the very basic/initial version of virtio-mem. An introduction to > virtio-mem can be found in the Linux kernel driver [1]. While it can be > used in the current state for hotplug of a smaller amount of memory, it > will heavily benefit from resizeable memory regions in the future. > > Each virtio-mem device manages a memory region (provided via a memory > backend). After requested by the hypervisor ("requested-size"), the > guest can try to plug/unplug blocks of memory within that region, in order > to reach the requested size. Initially, and after a reboot, all memory is > unplugged (except in special cases - reboot during postcopy). > > The guest may only try to plug/unplug blocks of memory within the usable > region size. The usable region size is a little bigger than the > requested size, to give the device driver some flexibility. The usable > region size will only grow, except on reboots or when all memory is > requested to get unplugged. The guest can never plug more memory than > requested. Unplugged memory will get zapped/discarded, similar to in a > balloon device. > > The block size is variable, however, it is always chosen in a way such that > THP splits are avoided (e.g., 2MB). The state of each block > (plugged/unplugged) is tracked in a bitmap. > > As virtio-mem devices (e.g., virtio-mem-pci) will be memory devices, we now > expose "VirtioMEMDeviceInfo" via "query-memory-devices". > > -------------------------------------------------------------------------- > > There are two important follow-up items that are in the works: > 1. Resizeable memory regions: Use resizeable allocations/RAM blocks to > grow/shrink along with the usable region size. This avoids creating > initially very big VMAs, RAM blocks, and KVM slots. > 2. Protection of unplugged memory: Make sure the gust cannot actually > make use of unplugged memory. > > Other follow-up items that are in the works: > 1. Exclude unplugged memory during migration (via precopy notifier). > 2. Handle remapping of memory. > 3. Support for other architectures. > > -------------------------------------------------------------------------- > > Example usage (virtio-mem-pci is introduced in follow-up patches): > > Start QEMU with two virtio-mem devices (one per NUMA node): > $ qemu-system-x86_64 -m 4G,maxmem=20G \ > -smp sockets=2,cores=2 \ > -numa node,nodeid=0,cpus=0-1 -numa node,nodeid=1,cpus=2-3 \ > [...] > -object memory-backend-ram,id=mem0,size=8G \ > -device virtio-mem-pci,id=vm0,memdev=mem0,node=0,requested-size=0M \ > -object memory-backend-ram,id=mem1,size=8G \ > -device virtio-mem-pci,id=vm1,memdev=mem1,node=1,requested-size=1G > > Query the configuration: > (qemu) info memory-devices > Memory device [virtio-mem]: "vm0" > memaddr: 0x140000000 > node: 0 > requested-size: 0 > size: 0 > max-size: 8589934592 > block-size: 2097152 > memdev: /objects/mem0 > Memory device [virtio-mem]: "vm1" > memaddr: 0x340000000 > node: 1 > requested-size: 1073741824 > size: 1073741824 > max-size: 8589934592 > block-size: 2097152 > memdev: /objects/mem1 > > Add some memory to node 0: > (qemu) qom-set vm0 requested-size 500M > > Remove some memory from node 1: > (qemu) qom-set vm1 requested-size 200M > > Query the configuration again: > (qemu) info memory-devices > Memory device [virtio-mem]: "vm0" > memaddr: 0x140000000 > node: 0 > requested-size: 524288000 > size: 524288000 > max-size: 8589934592 > block-size: 2097152 > memdev: /objects/mem0 > Memory device [virtio-mem]: "vm1" > memaddr: 0x340000000 > node: 1 > requested-size: 209715200 > size: 209715200 > max-size: 8589934592 > block-size: 2097152 > memdev: /objects/mem1 > > [1] https://lkml.kernel.org/r/20200311171422.10484-1-david@redhat.com > > Cc: "Michael S. Tsirkin" <mst@redhat.com> > Cc: Eric Blake <eblake@redhat.com> > Cc: Markus Armbruster <armbru@redhat.com> > Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> > Cc: Igor Mammedov <imammedo@redhat.com> > Signed-off-by: David Hildenbrand <david@redhat.com> > Message-Id: <20200626072248.78761-11-david@redhat.com> > Reviewed-by: Michael S. Tsirkin <mst@redhat.com> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > --- > qapi/misc.json | 39 +- > include/hw/virtio/virtio-mem.h | 78 ++++ > hw/virtio/virtio-mem.c | 724 +++++++++++++++++++++++++++++++++ > hw/virtio/Kconfig | 11 + > hw/virtio/Makefile.objs | 1 + > 5 files changed, 852 insertions(+), 1 deletion(-) > create mode 100644 include/hw/virtio/virtio-mem.h > create mode 100644 hw/virtio/virtio-mem.c > > diff --git a/qapi/misc.json b/qapi/misc.json > index a5a0beb902..65ca3edf32 100644 > --- a/qapi/misc.json > +++ b/qapi/misc.json > @@ -1356,19 +1356,56 @@ > } > } > > +## > +# @VirtioMEMDeviceInfo: > +# > +# VirtioMEMDevice state information > +# > +# @id: device's ID > +# > +# @memaddr: physical address in memory, where device is mapped > +# > +# @requested-size: the user requested size of the device > +# > +# @size: the (current) size of memory that the device provides > +# > +# @max-size: the maximum size of memory that the device can provide > +# > +# @block-size: the block size of memory that the device provides > +# > +# @node: NUMA node number where device is assigned to > +# > +# @memdev: memory backend linked with the region > +# > +# Since: 5.1 > +## > +{ 'struct': 'VirtioMEMDeviceInfo', > + 'data': { '*id': 'str', > + 'memaddr': 'size', > + 'requested-size': 'size', > + 'size': 'size', > + 'max-size': 'size', > + 'block-size': 'size', > + 'node': 'int', > + 'memdev': 'str' > + } > +} > + > ## > # @MemoryDeviceInfo: > # > # Union containing information about a memory device > # > # nvdimm is included since 2.12. virtio-pmem is included since 4.1. > +# virtio-mem is included since 5.1. > # > # Since: 2.1 > ## > { 'union': 'MemoryDeviceInfo', > 'data': { 'dimm': 'PCDIMMDeviceInfo', > 'nvdimm': 'PCDIMMDeviceInfo', > - 'virtio-pmem': 'VirtioPMEMDeviceInfo' > + 'virtio-pmem': 'VirtioPMEMDeviceInfo', > + 'virtio-mem': 'VirtioMEMDeviceInfo' > } > } > > diff --git a/include/hw/virtio/virtio-mem.h b/include/hw/virtio/virtio-mem.h > new file mode 100644 > index 0000000000..6981096f7c > --- /dev/null > +++ b/include/hw/virtio/virtio-mem.h > @@ -0,0 +1,78 @@ > +/* > + * Virtio MEM device > + * > + * Copyright (C) 2020 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_VIRTIO_MEM_H > +#define HW_VIRTIO_MEM_H > + > +#include "standard-headers/linux/virtio_mem.h" > +#include "hw/virtio/virtio.h" > +#include "qapi/qapi-types-misc.h" > +#include "sysemu/hostmem.h" > + > +#define TYPE_VIRTIO_MEM "virtio-mem" > + > +#define VIRTIO_MEM(obj) \ > + OBJECT_CHECK(VirtIOMEM, (obj), TYPE_VIRTIO_MEM) > +#define VIRTIO_MEM_CLASS(oc) \ > + OBJECT_CLASS_CHECK(VirtIOMEMClass, (oc), TYPE_VIRTIO_MEM) > +#define VIRTIO_MEM_GET_CLASS(obj) \ > + OBJECT_GET_CLASS(VirtIOMEMClass, (obj), TYPE_VIRTIO_MEM) > + > +#define VIRTIO_MEM_MEMDEV_PROP "memdev" > +#define VIRTIO_MEM_NODE_PROP "node" > +#define VIRTIO_MEM_SIZE_PROP "size" > +#define VIRTIO_MEM_REQUESTED_SIZE_PROP "requested-size" > +#define VIRTIO_MEM_BLOCK_SIZE_PROP "block-size" > +#define VIRTIO_MEM_ADDR_PROP "memaddr" > + > +typedef struct VirtIOMEM { > + VirtIODevice parent_obj; > + > + /* guest -> host request queue */ > + VirtQueue *vq; > + > + /* bitmap used to track unplugged memory */ > + int32_t bitmap_size; > + unsigned long *bitmap; > + > + /* assigned memory backend and memory region */ > + HostMemoryBackend *memdev; > + > + /* NUMA node */ > + uint32_t node; > + > + /* assigned address of the region in guest physical memory */ > + uint64_t addr; > + > + /* usable region size (<= region_size) */ > + uint64_t usable_region_size; > + > + /* actual size (how much the guest plugged) */ > + uint64_t size; > + > + /* requested size */ > + uint64_t requested_size; > + > + /* block size and alignment */ > + uint64_t block_size; > +} VirtIOMEM; > + > +typedef struct VirtIOMEMClass { > + /* private */ > + VirtIODevice parent; > + > + /* public */ > + void (*fill_device_info)(const VirtIOMEM *vmen, VirtioMEMDeviceInfo *vi); > + MemoryRegion *(*get_memory_region)(VirtIOMEM *vmem, Error **errp); > +} VirtIOMEMClass; > + > +#endif > diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c > new file mode 100644 > index 0000000000..d8a0c974d3 > --- /dev/null > +++ b/hw/virtio/virtio-mem.c > @@ -0,0 +1,724 @@ > +/* > + * Virtio MEM device > + * > + * Copyright (C) 2020 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 "qemu-common.h" > +#include "qemu/iov.h" > +#include "qemu/cutils.h" > +#include "qemu/error-report.h" > +#include "qemu/units.h" > +#include "sysemu/numa.h" > +#include "sysemu/sysemu.h" > +#include "sysemu/reset.h" > +#include "hw/virtio/virtio.h" > +#include "hw/virtio/virtio-bus.h" > +#include "hw/virtio/virtio-access.h" > +#include "hw/virtio/virtio-mem.h" > +#include "qapi/error.h" > +#include "qapi/visitor.h" > +#include "exec/ram_addr.h" > +#include "migration/misc.h" > +#include "hw/boards.h" > +#include "hw/qdev-properties.h" > +#include "config-devices.h" > + > +/* > + * Use QEMU_VMALLOC_ALIGN, so no THP will have to be split when unplugging > + * memory (e.g., 2MB on x86_64). > + */ > +#define VIRTIO_MEM_MIN_BLOCK_SIZE QEMU_VMALLOC_ALIGN > +/* > + * Size the usable region bigger than the requested size if possible. Esp. > + * Linux guests will only add (aligned) memory blocks in case they fully > + * fit into the usable region, but plug+online only a subset of the pages. > + * The memory block size corresponds mostly to the section size. > + * > + * This allows e.g., to add 20MB with a section size of 128MB on x86_64, and > + * a section size of 1GB on arm64 (as long as the start address is properly > + * aligned, similar to ordinary DIMMs). > + * > + * We can change this at any time and maybe even make it configurable if > + * necessary (as the section size can change). But it's more likely that the > + * section size will rather get smaller and not bigger over time. > + */ > +#if defined(__x86_64__) > +#define VIRTIO_MEM_USABLE_EXTENT (2 * (128 * MiB)) I just did a cross-compile on s390x and noticed that this should be guarded by defined(TARGET_X86_64) (it's target dependent). Sorry for the noise.
On 03.07.20 11:18, David Hildenbrand wrote: > On 03.07.20 11:04, Michael S. Tsirkin wrote: >> From: David Hildenbrand <david@redhat.com> >> >> This is the very basic/initial version of virtio-mem. An introduction to >> virtio-mem can be found in the Linux kernel driver [1]. While it can be >> used in the current state for hotplug of a smaller amount of memory, it >> will heavily benefit from resizeable memory regions in the future. >> >> Each virtio-mem device manages a memory region (provided via a memory >> backend). After requested by the hypervisor ("requested-size"), the >> guest can try to plug/unplug blocks of memory within that region, in order >> to reach the requested size. Initially, and after a reboot, all memory is >> unplugged (except in special cases - reboot during postcopy). >> >> The guest may only try to plug/unplug blocks of memory within the usable >> region size. The usable region size is a little bigger than the >> requested size, to give the device driver some flexibility. The usable >> region size will only grow, except on reboots or when all memory is >> requested to get unplugged. The guest can never plug more memory than >> requested. Unplugged memory will get zapped/discarded, similar to in a >> balloon device. >> >> The block size is variable, however, it is always chosen in a way such that >> THP splits are avoided (e.g., 2MB). The state of each block >> (plugged/unplugged) is tracked in a bitmap. >> >> As virtio-mem devices (e.g., virtio-mem-pci) will be memory devices, we now >> expose "VirtioMEMDeviceInfo" via "query-memory-devices". >> >> -------------------------------------------------------------------------- >> >> There are two important follow-up items that are in the works: >> 1. Resizeable memory regions: Use resizeable allocations/RAM blocks to >> grow/shrink along with the usable region size. This avoids creating >> initially very big VMAs, RAM blocks, and KVM slots. >> 2. Protection of unplugged memory: Make sure the gust cannot actually >> make use of unplugged memory. >> >> Other follow-up items that are in the works: >> 1. Exclude unplugged memory during migration (via precopy notifier). >> 2. Handle remapping of memory. >> 3. Support for other architectures. >> >> -------------------------------------------------------------------------- >> >> Example usage (virtio-mem-pci is introduced in follow-up patches): >> >> Start QEMU with two virtio-mem devices (one per NUMA node): >> $ qemu-system-x86_64 -m 4G,maxmem=20G \ >> -smp sockets=2,cores=2 \ >> -numa node,nodeid=0,cpus=0-1 -numa node,nodeid=1,cpus=2-3 \ >> [...] >> -object memory-backend-ram,id=mem0,size=8G \ >> -device virtio-mem-pci,id=vm0,memdev=mem0,node=0,requested-size=0M \ >> -object memory-backend-ram,id=mem1,size=8G \ >> -device virtio-mem-pci,id=vm1,memdev=mem1,node=1,requested-size=1G >> >> Query the configuration: >> (qemu) info memory-devices >> Memory device [virtio-mem]: "vm0" >> memaddr: 0x140000000 >> node: 0 >> requested-size: 0 >> size: 0 >> max-size: 8589934592 >> block-size: 2097152 >> memdev: /objects/mem0 >> Memory device [virtio-mem]: "vm1" >> memaddr: 0x340000000 >> node: 1 >> requested-size: 1073741824 >> size: 1073741824 >> max-size: 8589934592 >> block-size: 2097152 >> memdev: /objects/mem1 >> >> Add some memory to node 0: >> (qemu) qom-set vm0 requested-size 500M >> >> Remove some memory from node 1: >> (qemu) qom-set vm1 requested-size 200M >> >> Query the configuration again: >> (qemu) info memory-devices >> Memory device [virtio-mem]: "vm0" >> memaddr: 0x140000000 >> node: 0 >> requested-size: 524288000 >> size: 524288000 >> max-size: 8589934592 >> block-size: 2097152 >> memdev: /objects/mem0 >> Memory device [virtio-mem]: "vm1" >> memaddr: 0x340000000 >> node: 1 >> requested-size: 209715200 >> size: 209715200 >> max-size: 8589934592 >> block-size: 2097152 >> memdev: /objects/mem1 >> >> [1] https://lkml.kernel.org/r/20200311171422.10484-1-david@redhat.com >> >> Cc: "Michael S. Tsirkin" <mst@redhat.com> >> Cc: Eric Blake <eblake@redhat.com> >> Cc: Markus Armbruster <armbru@redhat.com> >> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> >> Cc: Igor Mammedov <imammedo@redhat.com> >> Signed-off-by: David Hildenbrand <david@redhat.com> >> Message-Id: <20200626072248.78761-11-david@redhat.com> >> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> >> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> >> --- >> qapi/misc.json | 39 +- >> include/hw/virtio/virtio-mem.h | 78 ++++ >> hw/virtio/virtio-mem.c | 724 +++++++++++++++++++++++++++++++++ >> hw/virtio/Kconfig | 11 + >> hw/virtio/Makefile.objs | 1 + >> 5 files changed, 852 insertions(+), 1 deletion(-) >> create mode 100644 include/hw/virtio/virtio-mem.h >> create mode 100644 hw/virtio/virtio-mem.c >> >> diff --git a/qapi/misc.json b/qapi/misc.json >> index a5a0beb902..65ca3edf32 100644 >> --- a/qapi/misc.json >> +++ b/qapi/misc.json >> @@ -1356,19 +1356,56 @@ >> } >> } >> >> +## >> +# @VirtioMEMDeviceInfo: >> +# >> +# VirtioMEMDevice state information >> +# >> +# @id: device's ID >> +# >> +# @memaddr: physical address in memory, where device is mapped >> +# >> +# @requested-size: the user requested size of the device >> +# >> +# @size: the (current) size of memory that the device provides >> +# >> +# @max-size: the maximum size of memory that the device can provide >> +# >> +# @block-size: the block size of memory that the device provides >> +# >> +# @node: NUMA node number where device is assigned to >> +# >> +# @memdev: memory backend linked with the region >> +# >> +# Since: 5.1 >> +## >> +{ 'struct': 'VirtioMEMDeviceInfo', >> + 'data': { '*id': 'str', >> + 'memaddr': 'size', >> + 'requested-size': 'size', >> + 'size': 'size', >> + 'max-size': 'size', >> + 'block-size': 'size', >> + 'node': 'int', >> + 'memdev': 'str' >> + } >> +} >> + >> ## >> # @MemoryDeviceInfo: >> # >> # Union containing information about a memory device >> # >> # nvdimm is included since 2.12. virtio-pmem is included since 4.1. >> +# virtio-mem is included since 5.1. >> # >> # Since: 2.1 >> ## >> { 'union': 'MemoryDeviceInfo', >> 'data': { 'dimm': 'PCDIMMDeviceInfo', >> 'nvdimm': 'PCDIMMDeviceInfo', >> - 'virtio-pmem': 'VirtioPMEMDeviceInfo' >> + 'virtio-pmem': 'VirtioPMEMDeviceInfo', >> + 'virtio-mem': 'VirtioMEMDeviceInfo' >> } >> } >> >> diff --git a/include/hw/virtio/virtio-mem.h b/include/hw/virtio/virtio-mem.h >> new file mode 100644 >> index 0000000000..6981096f7c >> --- /dev/null >> +++ b/include/hw/virtio/virtio-mem.h >> @@ -0,0 +1,78 @@ >> +/* >> + * Virtio MEM device >> + * >> + * Copyright (C) 2020 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_VIRTIO_MEM_H >> +#define HW_VIRTIO_MEM_H >> + >> +#include "standard-headers/linux/virtio_mem.h" >> +#include "hw/virtio/virtio.h" >> +#include "qapi/qapi-types-misc.h" >> +#include "sysemu/hostmem.h" >> + >> +#define TYPE_VIRTIO_MEM "virtio-mem" >> + >> +#define VIRTIO_MEM(obj) \ >> + OBJECT_CHECK(VirtIOMEM, (obj), TYPE_VIRTIO_MEM) >> +#define VIRTIO_MEM_CLASS(oc) \ >> + OBJECT_CLASS_CHECK(VirtIOMEMClass, (oc), TYPE_VIRTIO_MEM) >> +#define VIRTIO_MEM_GET_CLASS(obj) \ >> + OBJECT_GET_CLASS(VirtIOMEMClass, (obj), TYPE_VIRTIO_MEM) >> + >> +#define VIRTIO_MEM_MEMDEV_PROP "memdev" >> +#define VIRTIO_MEM_NODE_PROP "node" >> +#define VIRTIO_MEM_SIZE_PROP "size" >> +#define VIRTIO_MEM_REQUESTED_SIZE_PROP "requested-size" >> +#define VIRTIO_MEM_BLOCK_SIZE_PROP "block-size" >> +#define VIRTIO_MEM_ADDR_PROP "memaddr" >> + >> +typedef struct VirtIOMEM { >> + VirtIODevice parent_obj; >> + >> + /* guest -> host request queue */ >> + VirtQueue *vq; >> + >> + /* bitmap used to track unplugged memory */ >> + int32_t bitmap_size; >> + unsigned long *bitmap; >> + >> + /* assigned memory backend and memory region */ >> + HostMemoryBackend *memdev; >> + >> + /* NUMA node */ >> + uint32_t node; >> + >> + /* assigned address of the region in guest physical memory */ >> + uint64_t addr; >> + >> + /* usable region size (<= region_size) */ >> + uint64_t usable_region_size; >> + >> + /* actual size (how much the guest plugged) */ >> + uint64_t size; >> + >> + /* requested size */ >> + uint64_t requested_size; >> + >> + /* block size and alignment */ >> + uint64_t block_size; >> +} VirtIOMEM; >> + >> +typedef struct VirtIOMEMClass { >> + /* private */ >> + VirtIODevice parent; >> + >> + /* public */ >> + void (*fill_device_info)(const VirtIOMEM *vmen, VirtioMEMDeviceInfo *vi); >> + MemoryRegion *(*get_memory_region)(VirtIOMEM *vmem, Error **errp); >> +} VirtIOMEMClass; >> + >> +#endif >> diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c >> new file mode 100644 >> index 0000000000..d8a0c974d3 >> --- /dev/null >> +++ b/hw/virtio/virtio-mem.c >> @@ -0,0 +1,724 @@ >> +/* >> + * Virtio MEM device >> + * >> + * Copyright (C) 2020 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 "qemu-common.h" >> +#include "qemu/iov.h" >> +#include "qemu/cutils.h" >> +#include "qemu/error-report.h" >> +#include "qemu/units.h" >> +#include "sysemu/numa.h" >> +#include "sysemu/sysemu.h" >> +#include "sysemu/reset.h" >> +#include "hw/virtio/virtio.h" >> +#include "hw/virtio/virtio-bus.h" >> +#include "hw/virtio/virtio-access.h" >> +#include "hw/virtio/virtio-mem.h" >> +#include "qapi/error.h" >> +#include "qapi/visitor.h" >> +#include "exec/ram_addr.h" >> +#include "migration/misc.h" >> +#include "hw/boards.h" >> +#include "hw/qdev-properties.h" >> +#include "config-devices.h" >> + >> +/* >> + * Use QEMU_VMALLOC_ALIGN, so no THP will have to be split when unplugging >> + * memory (e.g., 2MB on x86_64). >> + */ >> +#define VIRTIO_MEM_MIN_BLOCK_SIZE QEMU_VMALLOC_ALIGN >> +/* >> + * Size the usable region bigger than the requested size if possible. Esp. >> + * Linux guests will only add (aligned) memory blocks in case they fully >> + * fit into the usable region, but plug+online only a subset of the pages. >> + * The memory block size corresponds mostly to the section size. >> + * >> + * This allows e.g., to add 20MB with a section size of 128MB on x86_64, and >> + * a section size of 1GB on arm64 (as long as the start address is properly >> + * aligned, similar to ordinary DIMMs). >> + * >> + * We can change this at any time and maybe even make it configurable if >> + * necessary (as the section size can change). But it's more likely that the >> + * section size will rather get smaller and not bigger over time. >> + */ >> +#if defined(__x86_64__) >> +#define VIRTIO_MEM_USABLE_EXTENT (2 * (128 * MiB)) > > I just did a cross-compile on s390x and noticed that this should be > guarded by defined(TARGET_X86_64) (it's target dependent). #if defined(TARGET_X86_64) || defined(TARGET_I386) to be precise.
On Fri, Jul 03, 2020 at 11:18:42AM +0200, David Hildenbrand wrote: > On 03.07.20 11:04, Michael S. Tsirkin wrote: > > From: David Hildenbrand <david@redhat.com> > > > > This is the very basic/initial version of virtio-mem. An introduction to > > virtio-mem can be found in the Linux kernel driver [1]. While it can be > > used in the current state for hotplug of a smaller amount of memory, it > > will heavily benefit from resizeable memory regions in the future. > > > > Each virtio-mem device manages a memory region (provided via a memory > > backend). After requested by the hypervisor ("requested-size"), the > > guest can try to plug/unplug blocks of memory within that region, in order > > to reach the requested size. Initially, and after a reboot, all memory is > > unplugged (except in special cases - reboot during postcopy). > > > > The guest may only try to plug/unplug blocks of memory within the usable > > region size. The usable region size is a little bigger than the > > requested size, to give the device driver some flexibility. The usable > > region size will only grow, except on reboots or when all memory is > > requested to get unplugged. The guest can never plug more memory than > > requested. Unplugged memory will get zapped/discarded, similar to in a > > balloon device. > > > > The block size is variable, however, it is always chosen in a way such that > > THP splits are avoided (e.g., 2MB). The state of each block > > (plugged/unplugged) is tracked in a bitmap. > > > > As virtio-mem devices (e.g., virtio-mem-pci) will be memory devices, we now > > expose "VirtioMEMDeviceInfo" via "query-memory-devices". > > > > -------------------------------------------------------------------------- > > > > There are two important follow-up items that are in the works: > > 1. Resizeable memory regions: Use resizeable allocations/RAM blocks to > > grow/shrink along with the usable region size. This avoids creating > > initially very big VMAs, RAM blocks, and KVM slots. > > 2. Protection of unplugged memory: Make sure the gust cannot actually > > make use of unplugged memory. > > > > Other follow-up items that are in the works: > > 1. Exclude unplugged memory during migration (via precopy notifier). > > 2. Handle remapping of memory. > > 3. Support for other architectures. > > > > -------------------------------------------------------------------------- > > > > Example usage (virtio-mem-pci is introduced in follow-up patches): > > > > Start QEMU with two virtio-mem devices (one per NUMA node): > > $ qemu-system-x86_64 -m 4G,maxmem=20G \ > > -smp sockets=2,cores=2 \ > > -numa node,nodeid=0,cpus=0-1 -numa node,nodeid=1,cpus=2-3 \ > > [...] > > -object memory-backend-ram,id=mem0,size=8G \ > > -device virtio-mem-pci,id=vm0,memdev=mem0,node=0,requested-size=0M \ > > -object memory-backend-ram,id=mem1,size=8G \ > > -device virtio-mem-pci,id=vm1,memdev=mem1,node=1,requested-size=1G > > > > Query the configuration: > > (qemu) info memory-devices > > Memory device [virtio-mem]: "vm0" > > memaddr: 0x140000000 > > node: 0 > > requested-size: 0 > > size: 0 > > max-size: 8589934592 > > block-size: 2097152 > > memdev: /objects/mem0 > > Memory device [virtio-mem]: "vm1" > > memaddr: 0x340000000 > > node: 1 > > requested-size: 1073741824 > > size: 1073741824 > > max-size: 8589934592 > > block-size: 2097152 > > memdev: /objects/mem1 > > > > Add some memory to node 0: > > (qemu) qom-set vm0 requested-size 500M > > > > Remove some memory from node 1: > > (qemu) qom-set vm1 requested-size 200M > > > > Query the configuration again: > > (qemu) info memory-devices > > Memory device [virtio-mem]: "vm0" > > memaddr: 0x140000000 > > node: 0 > > requested-size: 524288000 > > size: 524288000 > > max-size: 8589934592 > > block-size: 2097152 > > memdev: /objects/mem0 > > Memory device [virtio-mem]: "vm1" > > memaddr: 0x340000000 > > node: 1 > > requested-size: 209715200 > > size: 209715200 > > max-size: 8589934592 > > block-size: 2097152 > > memdev: /objects/mem1 > > > > [1] https://lkml.kernel.org/r/20200311171422.10484-1-david@redhat.com > > > > Cc: "Michael S. Tsirkin" <mst@redhat.com> > > Cc: Eric Blake <eblake@redhat.com> > > Cc: Markus Armbruster <armbru@redhat.com> > > Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> > > Cc: Igor Mammedov <imammedo@redhat.com> > > Signed-off-by: David Hildenbrand <david@redhat.com> > > Message-Id: <20200626072248.78761-11-david@redhat.com> > > Reviewed-by: Michael S. Tsirkin <mst@redhat.com> > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > > --- > > qapi/misc.json | 39 +- > > include/hw/virtio/virtio-mem.h | 78 ++++ > > hw/virtio/virtio-mem.c | 724 +++++++++++++++++++++++++++++++++ > > hw/virtio/Kconfig | 11 + > > hw/virtio/Makefile.objs | 1 + > > 5 files changed, 852 insertions(+), 1 deletion(-) > > create mode 100644 include/hw/virtio/virtio-mem.h > > create mode 100644 hw/virtio/virtio-mem.c > > > > diff --git a/qapi/misc.json b/qapi/misc.json > > index a5a0beb902..65ca3edf32 100644 > > --- a/qapi/misc.json > > +++ b/qapi/misc.json > > @@ -1356,19 +1356,56 @@ > > } > > } > > > > +## > > +# @VirtioMEMDeviceInfo: > > +# > > +# VirtioMEMDevice state information > > +# > > +# @id: device's ID > > +# > > +# @memaddr: physical address in memory, where device is mapped > > +# > > +# @requested-size: the user requested size of the device > > +# > > +# @size: the (current) size of memory that the device provides > > +# > > +# @max-size: the maximum size of memory that the device can provide > > +# > > +# @block-size: the block size of memory that the device provides > > +# > > +# @node: NUMA node number where device is assigned to > > +# > > +# @memdev: memory backend linked with the region > > +# > > +# Since: 5.1 > > +## > > +{ 'struct': 'VirtioMEMDeviceInfo', > > + 'data': { '*id': 'str', > > + 'memaddr': 'size', > > + 'requested-size': 'size', > > + 'size': 'size', > > + 'max-size': 'size', > > + 'block-size': 'size', > > + 'node': 'int', > > + 'memdev': 'str' > > + } > > +} > > + > > ## > > # @MemoryDeviceInfo: > > # > > # Union containing information about a memory device > > # > > # nvdimm is included since 2.12. virtio-pmem is included since 4.1. > > +# virtio-mem is included since 5.1. > > # > > # Since: 2.1 > > ## > > { 'union': 'MemoryDeviceInfo', > > 'data': { 'dimm': 'PCDIMMDeviceInfo', > > 'nvdimm': 'PCDIMMDeviceInfo', > > - 'virtio-pmem': 'VirtioPMEMDeviceInfo' > > + 'virtio-pmem': 'VirtioPMEMDeviceInfo', > > + 'virtio-mem': 'VirtioMEMDeviceInfo' > > } > > } > > > > diff --git a/include/hw/virtio/virtio-mem.h b/include/hw/virtio/virtio-mem.h > > new file mode 100644 > > index 0000000000..6981096f7c > > --- /dev/null > > +++ b/include/hw/virtio/virtio-mem.h > > @@ -0,0 +1,78 @@ > > +/* > > + * Virtio MEM device > > + * > > + * Copyright (C) 2020 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_VIRTIO_MEM_H > > +#define HW_VIRTIO_MEM_H > > + > > +#include "standard-headers/linux/virtio_mem.h" > > +#include "hw/virtio/virtio.h" > > +#include "qapi/qapi-types-misc.h" > > +#include "sysemu/hostmem.h" > > + > > +#define TYPE_VIRTIO_MEM "virtio-mem" > > + > > +#define VIRTIO_MEM(obj) \ > > + OBJECT_CHECK(VirtIOMEM, (obj), TYPE_VIRTIO_MEM) > > +#define VIRTIO_MEM_CLASS(oc) \ > > + OBJECT_CLASS_CHECK(VirtIOMEMClass, (oc), TYPE_VIRTIO_MEM) > > +#define VIRTIO_MEM_GET_CLASS(obj) \ > > + OBJECT_GET_CLASS(VirtIOMEMClass, (obj), TYPE_VIRTIO_MEM) > > + > > +#define VIRTIO_MEM_MEMDEV_PROP "memdev" > > +#define VIRTIO_MEM_NODE_PROP "node" > > +#define VIRTIO_MEM_SIZE_PROP "size" > > +#define VIRTIO_MEM_REQUESTED_SIZE_PROP "requested-size" > > +#define VIRTIO_MEM_BLOCK_SIZE_PROP "block-size" > > +#define VIRTIO_MEM_ADDR_PROP "memaddr" > > + > > +typedef struct VirtIOMEM { > > + VirtIODevice parent_obj; > > + > > + /* guest -> host request queue */ > > + VirtQueue *vq; > > + > > + /* bitmap used to track unplugged memory */ > > + int32_t bitmap_size; > > + unsigned long *bitmap; > > + > > + /* assigned memory backend and memory region */ > > + HostMemoryBackend *memdev; > > + > > + /* NUMA node */ > > + uint32_t node; > > + > > + /* assigned address of the region in guest physical memory */ > > + uint64_t addr; > > + > > + /* usable region size (<= region_size) */ > > + uint64_t usable_region_size; > > + > > + /* actual size (how much the guest plugged) */ > > + uint64_t size; > > + > > + /* requested size */ > > + uint64_t requested_size; > > + > > + /* block size and alignment */ > > + uint64_t block_size; > > +} VirtIOMEM; > > + > > +typedef struct VirtIOMEMClass { > > + /* private */ > > + VirtIODevice parent; > > + > > + /* public */ > > + void (*fill_device_info)(const VirtIOMEM *vmen, VirtioMEMDeviceInfo *vi); > > + MemoryRegion *(*get_memory_region)(VirtIOMEM *vmem, Error **errp); > > +} VirtIOMEMClass; > > + > > +#endif > > diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c > > new file mode 100644 > > index 0000000000..d8a0c974d3 > > --- /dev/null > > +++ b/hw/virtio/virtio-mem.c > > @@ -0,0 +1,724 @@ > > +/* > > + * Virtio MEM device > > + * > > + * Copyright (C) 2020 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 "qemu-common.h" > > +#include "qemu/iov.h" > > +#include "qemu/cutils.h" > > +#include "qemu/error-report.h" > > +#include "qemu/units.h" > > +#include "sysemu/numa.h" > > +#include "sysemu/sysemu.h" > > +#include "sysemu/reset.h" > > +#include "hw/virtio/virtio.h" > > +#include "hw/virtio/virtio-bus.h" > > +#include "hw/virtio/virtio-access.h" > > +#include "hw/virtio/virtio-mem.h" > > +#include "qapi/error.h" > > +#include "qapi/visitor.h" > > +#include "exec/ram_addr.h" > > +#include "migration/misc.h" > > +#include "hw/boards.h" > > +#include "hw/qdev-properties.h" > > +#include "config-devices.h" > > + > > +/* > > + * Use QEMU_VMALLOC_ALIGN, so no THP will have to be split when unplugging > > + * memory (e.g., 2MB on x86_64). > > + */ > > +#define VIRTIO_MEM_MIN_BLOCK_SIZE QEMU_VMALLOC_ALIGN > > +/* > > + * Size the usable region bigger than the requested size if possible. Esp. > > + * Linux guests will only add (aligned) memory blocks in case they fully > > + * fit into the usable region, but plug+online only a subset of the pages. > > + * The memory block size corresponds mostly to the section size. > > + * > > + * This allows e.g., to add 20MB with a section size of 128MB on x86_64, and > > + * a section size of 1GB on arm64 (as long as the start address is properly > > + * aligned, similar to ordinary DIMMs). > > + * > > + * We can change this at any time and maybe even make it configurable if > > + * necessary (as the section size can change). But it's more likely that the > > + * section size will rather get smaller and not bigger over time. > > + */ > > +#if defined(__x86_64__) > > +#define VIRTIO_MEM_USABLE_EXTENT (2 * (128 * MiB)) > > I just did a cross-compile on s390x and noticed that this should be > guarded by defined(TARGET_X86_64) (it's target dependent). > > Sorry for the noise. > > -- > Thanks, > > David / dhildenb OK - can you post a fixup patch pls?
On 03.07.20 12:23, Michael S. Tsirkin wrote: > On Fri, Jul 03, 2020 at 11:18:42AM +0200, David Hildenbrand wrote: >> On 03.07.20 11:04, Michael S. Tsirkin wrote: >>> From: David Hildenbrand <david@redhat.com> >>> >>> This is the very basic/initial version of virtio-mem. An introduction to >>> virtio-mem can be found in the Linux kernel driver [1]. While it can be >>> used in the current state for hotplug of a smaller amount of memory, it >>> will heavily benefit from resizeable memory regions in the future. >>> >>> Each virtio-mem device manages a memory region (provided via a memory >>> backend). After requested by the hypervisor ("requested-size"), the >>> guest can try to plug/unplug blocks of memory within that region, in order >>> to reach the requested size. Initially, and after a reboot, all memory is >>> unplugged (except in special cases - reboot during postcopy). >>> >>> The guest may only try to plug/unplug blocks of memory within the usable >>> region size. The usable region size is a little bigger than the >>> requested size, to give the device driver some flexibility. The usable >>> region size will only grow, except on reboots or when all memory is >>> requested to get unplugged. The guest can never plug more memory than >>> requested. Unplugged memory will get zapped/discarded, similar to in a >>> balloon device. >>> >>> The block size is variable, however, it is always chosen in a way such that >>> THP splits are avoided (e.g., 2MB). The state of each block >>> (plugged/unplugged) is tracked in a bitmap. >>> >>> As virtio-mem devices (e.g., virtio-mem-pci) will be memory devices, we now >>> expose "VirtioMEMDeviceInfo" via "query-memory-devices". >>> >>> -------------------------------------------------------------------------- >>> >>> There are two important follow-up items that are in the works: >>> 1. Resizeable memory regions: Use resizeable allocations/RAM blocks to >>> grow/shrink along with the usable region size. This avoids creating >>> initially very big VMAs, RAM blocks, and KVM slots. >>> 2. Protection of unplugged memory: Make sure the gust cannot actually >>> make use of unplugged memory. >>> >>> Other follow-up items that are in the works: >>> 1. Exclude unplugged memory during migration (via precopy notifier). >>> 2. Handle remapping of memory. >>> 3. Support for other architectures. >>> >>> -------------------------------------------------------------------------- >>> >>> Example usage (virtio-mem-pci is introduced in follow-up patches): >>> >>> Start QEMU with two virtio-mem devices (one per NUMA node): >>> $ qemu-system-x86_64 -m 4G,maxmem=20G \ >>> -smp sockets=2,cores=2 \ >>> -numa node,nodeid=0,cpus=0-1 -numa node,nodeid=1,cpus=2-3 \ >>> [...] >>> -object memory-backend-ram,id=mem0,size=8G \ >>> -device virtio-mem-pci,id=vm0,memdev=mem0,node=0,requested-size=0M \ >>> -object memory-backend-ram,id=mem1,size=8G \ >>> -device virtio-mem-pci,id=vm1,memdev=mem1,node=1,requested-size=1G >>> >>> Query the configuration: >>> (qemu) info memory-devices >>> Memory device [virtio-mem]: "vm0" >>> memaddr: 0x140000000 >>> node: 0 >>> requested-size: 0 >>> size: 0 >>> max-size: 8589934592 >>> block-size: 2097152 >>> memdev: /objects/mem0 >>> Memory device [virtio-mem]: "vm1" >>> memaddr: 0x340000000 >>> node: 1 >>> requested-size: 1073741824 >>> size: 1073741824 >>> max-size: 8589934592 >>> block-size: 2097152 >>> memdev: /objects/mem1 >>> >>> Add some memory to node 0: >>> (qemu) qom-set vm0 requested-size 500M >>> >>> Remove some memory from node 1: >>> (qemu) qom-set vm1 requested-size 200M >>> >>> Query the configuration again: >>> (qemu) info memory-devices >>> Memory device [virtio-mem]: "vm0" >>> memaddr: 0x140000000 >>> node: 0 >>> requested-size: 524288000 >>> size: 524288000 >>> max-size: 8589934592 >>> block-size: 2097152 >>> memdev: /objects/mem0 >>> Memory device [virtio-mem]: "vm1" >>> memaddr: 0x340000000 >>> node: 1 >>> requested-size: 209715200 >>> size: 209715200 >>> max-size: 8589934592 >>> block-size: 2097152 >>> memdev: /objects/mem1 >>> >>> [1] https://lkml.kernel.org/r/20200311171422.10484-1-david@redhat.com >>> >>> Cc: "Michael S. Tsirkin" <mst@redhat.com> >>> Cc: Eric Blake <eblake@redhat.com> >>> Cc: Markus Armbruster <armbru@redhat.com> >>> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> >>> Cc: Igor Mammedov <imammedo@redhat.com> >>> Signed-off-by: David Hildenbrand <david@redhat.com> >>> Message-Id: <20200626072248.78761-11-david@redhat.com> >>> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> >>> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> >>> --- >>> qapi/misc.json | 39 +- >>> include/hw/virtio/virtio-mem.h | 78 ++++ >>> hw/virtio/virtio-mem.c | 724 +++++++++++++++++++++++++++++++++ >>> hw/virtio/Kconfig | 11 + >>> hw/virtio/Makefile.objs | 1 + >>> 5 files changed, 852 insertions(+), 1 deletion(-) >>> create mode 100644 include/hw/virtio/virtio-mem.h >>> create mode 100644 hw/virtio/virtio-mem.c >>> >>> diff --git a/qapi/misc.json b/qapi/misc.json >>> index a5a0beb902..65ca3edf32 100644 >>> --- a/qapi/misc.json >>> +++ b/qapi/misc.json >>> @@ -1356,19 +1356,56 @@ >>> } >>> } >>> >>> +## >>> +# @VirtioMEMDeviceInfo: >>> +# >>> +# VirtioMEMDevice state information >>> +# >>> +# @id: device's ID >>> +# >>> +# @memaddr: physical address in memory, where device is mapped >>> +# >>> +# @requested-size: the user requested size of the device >>> +# >>> +# @size: the (current) size of memory that the device provides >>> +# >>> +# @max-size: the maximum size of memory that the device can provide >>> +# >>> +# @block-size: the block size of memory that the device provides >>> +# >>> +# @node: NUMA node number where device is assigned to >>> +# >>> +# @memdev: memory backend linked with the region >>> +# >>> +# Since: 5.1 >>> +## >>> +{ 'struct': 'VirtioMEMDeviceInfo', >>> + 'data': { '*id': 'str', >>> + 'memaddr': 'size', >>> + 'requested-size': 'size', >>> + 'size': 'size', >>> + 'max-size': 'size', >>> + 'block-size': 'size', >>> + 'node': 'int', >>> + 'memdev': 'str' >>> + } >>> +} >>> + >>> ## >>> # @MemoryDeviceInfo: >>> # >>> # Union containing information about a memory device >>> # >>> # nvdimm is included since 2.12. virtio-pmem is included since 4.1. >>> +# virtio-mem is included since 5.1. >>> # >>> # Since: 2.1 >>> ## >>> { 'union': 'MemoryDeviceInfo', >>> 'data': { 'dimm': 'PCDIMMDeviceInfo', >>> 'nvdimm': 'PCDIMMDeviceInfo', >>> - 'virtio-pmem': 'VirtioPMEMDeviceInfo' >>> + 'virtio-pmem': 'VirtioPMEMDeviceInfo', >>> + 'virtio-mem': 'VirtioMEMDeviceInfo' >>> } >>> } >>> >>> diff --git a/include/hw/virtio/virtio-mem.h b/include/hw/virtio/virtio-mem.h >>> new file mode 100644 >>> index 0000000000..6981096f7c >>> --- /dev/null >>> +++ b/include/hw/virtio/virtio-mem.h >>> @@ -0,0 +1,78 @@ >>> +/* >>> + * Virtio MEM device >>> + * >>> + * Copyright (C) 2020 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_VIRTIO_MEM_H >>> +#define HW_VIRTIO_MEM_H >>> + >>> +#include "standard-headers/linux/virtio_mem.h" >>> +#include "hw/virtio/virtio.h" >>> +#include "qapi/qapi-types-misc.h" >>> +#include "sysemu/hostmem.h" >>> + >>> +#define TYPE_VIRTIO_MEM "virtio-mem" >>> + >>> +#define VIRTIO_MEM(obj) \ >>> + OBJECT_CHECK(VirtIOMEM, (obj), TYPE_VIRTIO_MEM) >>> +#define VIRTIO_MEM_CLASS(oc) \ >>> + OBJECT_CLASS_CHECK(VirtIOMEMClass, (oc), TYPE_VIRTIO_MEM) >>> +#define VIRTIO_MEM_GET_CLASS(obj) \ >>> + OBJECT_GET_CLASS(VirtIOMEMClass, (obj), TYPE_VIRTIO_MEM) >>> + >>> +#define VIRTIO_MEM_MEMDEV_PROP "memdev" >>> +#define VIRTIO_MEM_NODE_PROP "node" >>> +#define VIRTIO_MEM_SIZE_PROP "size" >>> +#define VIRTIO_MEM_REQUESTED_SIZE_PROP "requested-size" >>> +#define VIRTIO_MEM_BLOCK_SIZE_PROP "block-size" >>> +#define VIRTIO_MEM_ADDR_PROP "memaddr" >>> + >>> +typedef struct VirtIOMEM { >>> + VirtIODevice parent_obj; >>> + >>> + /* guest -> host request queue */ >>> + VirtQueue *vq; >>> + >>> + /* bitmap used to track unplugged memory */ >>> + int32_t bitmap_size; >>> + unsigned long *bitmap; >>> + >>> + /* assigned memory backend and memory region */ >>> + HostMemoryBackend *memdev; >>> + >>> + /* NUMA node */ >>> + uint32_t node; >>> + >>> + /* assigned address of the region in guest physical memory */ >>> + uint64_t addr; >>> + >>> + /* usable region size (<= region_size) */ >>> + uint64_t usable_region_size; >>> + >>> + /* actual size (how much the guest plugged) */ >>> + uint64_t size; >>> + >>> + /* requested size */ >>> + uint64_t requested_size; >>> + >>> + /* block size and alignment */ >>> + uint64_t block_size; >>> +} VirtIOMEM; >>> + >>> +typedef struct VirtIOMEMClass { >>> + /* private */ >>> + VirtIODevice parent; >>> + >>> + /* public */ >>> + void (*fill_device_info)(const VirtIOMEM *vmen, VirtioMEMDeviceInfo *vi); >>> + MemoryRegion *(*get_memory_region)(VirtIOMEM *vmem, Error **errp); >>> +} VirtIOMEMClass; >>> + >>> +#endif >>> diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c >>> new file mode 100644 >>> index 0000000000..d8a0c974d3 >>> --- /dev/null >>> +++ b/hw/virtio/virtio-mem.c >>> @@ -0,0 +1,724 @@ >>> +/* >>> + * Virtio MEM device >>> + * >>> + * Copyright (C) 2020 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 "qemu-common.h" >>> +#include "qemu/iov.h" >>> +#include "qemu/cutils.h" >>> +#include "qemu/error-report.h" >>> +#include "qemu/units.h" >>> +#include "sysemu/numa.h" >>> +#include "sysemu/sysemu.h" >>> +#include "sysemu/reset.h" >>> +#include "hw/virtio/virtio.h" >>> +#include "hw/virtio/virtio-bus.h" >>> +#include "hw/virtio/virtio-access.h" >>> +#include "hw/virtio/virtio-mem.h" >>> +#include "qapi/error.h" >>> +#include "qapi/visitor.h" >>> +#include "exec/ram_addr.h" >>> +#include "migration/misc.h" >>> +#include "hw/boards.h" >>> +#include "hw/qdev-properties.h" >>> +#include "config-devices.h" >>> + >>> +/* >>> + * Use QEMU_VMALLOC_ALIGN, so no THP will have to be split when unplugging >>> + * memory (e.g., 2MB on x86_64). >>> + */ >>> +#define VIRTIO_MEM_MIN_BLOCK_SIZE QEMU_VMALLOC_ALIGN >>> +/* >>> + * Size the usable region bigger than the requested size if possible. Esp. >>> + * Linux guests will only add (aligned) memory blocks in case they fully >>> + * fit into the usable region, but plug+online only a subset of the pages. >>> + * The memory block size corresponds mostly to the section size. >>> + * >>> + * This allows e.g., to add 20MB with a section size of 128MB on x86_64, and >>> + * a section size of 1GB on arm64 (as long as the start address is properly >>> + * aligned, similar to ordinary DIMMs). >>> + * >>> + * We can change this at any time and maybe even make it configurable if >>> + * necessary (as the section size can change). But it's more likely that the >>> + * section size will rather get smaller and not bigger over time. >>> + */ >>> +#if defined(__x86_64__) >>> +#define VIRTIO_MEM_USABLE_EXTENT (2 * (128 * MiB)) >> >> I just did a cross-compile on s390x and noticed that this should be >> guarded by defined(TARGET_X86_64) (it's target dependent). >> >> Sorry for the noise. >> >> -- >> Thanks, >> >> David / dhildenb > > > OK - can you post a fixup patch pls? Yep, thanks!
diff --git a/qapi/misc.json b/qapi/misc.json index a5a0beb902..65ca3edf32 100644 --- a/qapi/misc.json +++ b/qapi/misc.json @@ -1356,19 +1356,56 @@ } } +## +# @VirtioMEMDeviceInfo: +# +# VirtioMEMDevice state information +# +# @id: device's ID +# +# @memaddr: physical address in memory, where device is mapped +# +# @requested-size: the user requested size of the device +# +# @size: the (current) size of memory that the device provides +# +# @max-size: the maximum size of memory that the device can provide +# +# @block-size: the block size of memory that the device provides +# +# @node: NUMA node number where device is assigned to +# +# @memdev: memory backend linked with the region +# +# Since: 5.1 +## +{ 'struct': 'VirtioMEMDeviceInfo', + 'data': { '*id': 'str', + 'memaddr': 'size', + 'requested-size': 'size', + 'size': 'size', + 'max-size': 'size', + 'block-size': 'size', + 'node': 'int', + 'memdev': 'str' + } +} + ## # @MemoryDeviceInfo: # # Union containing information about a memory device # # nvdimm is included since 2.12. virtio-pmem is included since 4.1. +# virtio-mem is included since 5.1. # # Since: 2.1 ## { 'union': 'MemoryDeviceInfo', 'data': { 'dimm': 'PCDIMMDeviceInfo', 'nvdimm': 'PCDIMMDeviceInfo', - 'virtio-pmem': 'VirtioPMEMDeviceInfo' + 'virtio-pmem': 'VirtioPMEMDeviceInfo', + 'virtio-mem': 'VirtioMEMDeviceInfo' } } diff --git a/include/hw/virtio/virtio-mem.h b/include/hw/virtio/virtio-mem.h new file mode 100644 index 0000000000..6981096f7c --- /dev/null +++ b/include/hw/virtio/virtio-mem.h @@ -0,0 +1,78 @@ +/* + * Virtio MEM device + * + * Copyright (C) 2020 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_VIRTIO_MEM_H +#define HW_VIRTIO_MEM_H + +#include "standard-headers/linux/virtio_mem.h" +#include "hw/virtio/virtio.h" +#include "qapi/qapi-types-misc.h" +#include "sysemu/hostmem.h" + +#define TYPE_VIRTIO_MEM "virtio-mem" + +#define VIRTIO_MEM(obj) \ + OBJECT_CHECK(VirtIOMEM, (obj), TYPE_VIRTIO_MEM) +#define VIRTIO_MEM_CLASS(oc) \ + OBJECT_CLASS_CHECK(VirtIOMEMClass, (oc), TYPE_VIRTIO_MEM) +#define VIRTIO_MEM_GET_CLASS(obj) \ + OBJECT_GET_CLASS(VirtIOMEMClass, (obj), TYPE_VIRTIO_MEM) + +#define VIRTIO_MEM_MEMDEV_PROP "memdev" +#define VIRTIO_MEM_NODE_PROP "node" +#define VIRTIO_MEM_SIZE_PROP "size" +#define VIRTIO_MEM_REQUESTED_SIZE_PROP "requested-size" +#define VIRTIO_MEM_BLOCK_SIZE_PROP "block-size" +#define VIRTIO_MEM_ADDR_PROP "memaddr" + +typedef struct VirtIOMEM { + VirtIODevice parent_obj; + + /* guest -> host request queue */ + VirtQueue *vq; + + /* bitmap used to track unplugged memory */ + int32_t bitmap_size; + unsigned long *bitmap; + + /* assigned memory backend and memory region */ + HostMemoryBackend *memdev; + + /* NUMA node */ + uint32_t node; + + /* assigned address of the region in guest physical memory */ + uint64_t addr; + + /* usable region size (<= region_size) */ + uint64_t usable_region_size; + + /* actual size (how much the guest plugged) */ + uint64_t size; + + /* requested size */ + uint64_t requested_size; + + /* block size and alignment */ + uint64_t block_size; +} VirtIOMEM; + +typedef struct VirtIOMEMClass { + /* private */ + VirtIODevice parent; + + /* public */ + void (*fill_device_info)(const VirtIOMEM *vmen, VirtioMEMDeviceInfo *vi); + MemoryRegion *(*get_memory_region)(VirtIOMEM *vmem, Error **errp); +} VirtIOMEMClass; + +#endif diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c new file mode 100644 index 0000000000..d8a0c974d3 --- /dev/null +++ b/hw/virtio/virtio-mem.c @@ -0,0 +1,724 @@ +/* + * Virtio MEM device + * + * Copyright (C) 2020 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 "qemu-common.h" +#include "qemu/iov.h" +#include "qemu/cutils.h" +#include "qemu/error-report.h" +#include "qemu/units.h" +#include "sysemu/numa.h" +#include "sysemu/sysemu.h" +#include "sysemu/reset.h" +#include "hw/virtio/virtio.h" +#include "hw/virtio/virtio-bus.h" +#include "hw/virtio/virtio-access.h" +#include "hw/virtio/virtio-mem.h" +#include "qapi/error.h" +#include "qapi/visitor.h" +#include "exec/ram_addr.h" +#include "migration/misc.h" +#include "hw/boards.h" +#include "hw/qdev-properties.h" +#include "config-devices.h" + +/* + * Use QEMU_VMALLOC_ALIGN, so no THP will have to be split when unplugging + * memory (e.g., 2MB on x86_64). + */ +#define VIRTIO_MEM_MIN_BLOCK_SIZE QEMU_VMALLOC_ALIGN +/* + * Size the usable region bigger than the requested size if possible. Esp. + * Linux guests will only add (aligned) memory blocks in case they fully + * fit into the usable region, but plug+online only a subset of the pages. + * The memory block size corresponds mostly to the section size. + * + * This allows e.g., to add 20MB with a section size of 128MB on x86_64, and + * a section size of 1GB on arm64 (as long as the start address is properly + * aligned, similar to ordinary DIMMs). + * + * We can change this at any time and maybe even make it configurable if + * necessary (as the section size can change). But it's more likely that the + * section size will rather get smaller and not bigger over time. + */ +#if defined(__x86_64__) +#define VIRTIO_MEM_USABLE_EXTENT (2 * (128 * MiB)) +#else +#error VIRTIO_MEM_USABLE_EXTENT not defined +#endif + +static bool virtio_mem_is_busy(void) +{ + /* + * Postcopy cannot handle concurrent discards and we don't want to migrate + * pages on-demand with stale content when plugging new blocks. + */ + return migration_in_incoming_postcopy(); +} + +static bool virtio_mem_test_bitmap(VirtIOMEM *vmem, uint64_t start_gpa, + uint64_t size, bool plugged) +{ + const unsigned long first_bit = (start_gpa - vmem->addr) / vmem->block_size; + const unsigned long last_bit = first_bit + (size / vmem->block_size) - 1; + unsigned long found_bit; + + /* We fake a shorter bitmap to avoid searching too far. */ + if (plugged) { + found_bit = find_next_zero_bit(vmem->bitmap, last_bit + 1, first_bit); + } else { + found_bit = find_next_bit(vmem->bitmap, last_bit + 1, first_bit); + } + return found_bit > last_bit; +} + +static void virtio_mem_set_bitmap(VirtIOMEM *vmem, uint64_t start_gpa, + uint64_t size, bool plugged) +{ + const unsigned long bit = (start_gpa - vmem->addr) / vmem->block_size; + const unsigned long nbits = size / vmem->block_size; + + if (plugged) { + bitmap_set(vmem->bitmap, bit, nbits); + } else { + bitmap_clear(vmem->bitmap, bit, nbits); + } +} + +static void virtio_mem_send_response(VirtIOMEM *vmem, VirtQueueElement *elem, + struct virtio_mem_resp *resp) +{ + VirtIODevice *vdev = VIRTIO_DEVICE(vmem); + VirtQueue *vq = vmem->vq; + + iov_from_buf(elem->in_sg, elem->in_num, 0, resp, sizeof(*resp)); + + virtqueue_push(vq, elem, sizeof(*resp)); + virtio_notify(vdev, vq); +} + +static void virtio_mem_send_response_simple(VirtIOMEM *vmem, + VirtQueueElement *elem, + uint16_t type) +{ + struct virtio_mem_resp resp = { + .type = cpu_to_le16(type), + }; + + virtio_mem_send_response(vmem, elem, &resp); +} + +static bool virtio_mem_valid_range(VirtIOMEM *vmem, uint64_t gpa, uint64_t size) +{ + if (!QEMU_IS_ALIGNED(gpa, vmem->block_size)) { + return false; + } + if (gpa + size < gpa || !size) { + return false; + } + if (gpa < vmem->addr || gpa >= vmem->addr + vmem->usable_region_size) { + return false; + } + if (gpa + size > vmem->addr + vmem->usable_region_size) { + return false; + } + return true; +} + +static int virtio_mem_set_block_state(VirtIOMEM *vmem, uint64_t start_gpa, + uint64_t size, bool plug) +{ + const uint64_t offset = start_gpa - vmem->addr; + int ret; + + if (virtio_mem_is_busy()) { + return -EBUSY; + } + + if (!plug) { + ret = ram_block_discard_range(vmem->memdev->mr.ram_block, offset, size); + if (ret) { + error_report("Unexpected error discarding RAM: %s", + strerror(-ret)); + return -EBUSY; + } + } + virtio_mem_set_bitmap(vmem, start_gpa, size, plug); + return 0; +} + +static int virtio_mem_state_change_request(VirtIOMEM *vmem, uint64_t gpa, + uint16_t nb_blocks, bool plug) +{ + const uint64_t size = nb_blocks * vmem->block_size; + int ret; + + if (!virtio_mem_valid_range(vmem, gpa, size)) { + return VIRTIO_MEM_RESP_ERROR; + } + + if (plug && (vmem->size + size > vmem->requested_size)) { + return VIRTIO_MEM_RESP_NACK; + } + + /* test if really all blocks are in the opposite state */ + if (!virtio_mem_test_bitmap(vmem, gpa, size, !plug)) { + return VIRTIO_MEM_RESP_ERROR; + } + + ret = virtio_mem_set_block_state(vmem, gpa, size, plug); + if (ret) { + return VIRTIO_MEM_RESP_BUSY; + } + if (plug) { + vmem->size += size; + } else { + vmem->size -= size; + } + return VIRTIO_MEM_RESP_ACK; +} + +static void virtio_mem_plug_request(VirtIOMEM *vmem, VirtQueueElement *elem, + struct virtio_mem_req *req) +{ + const uint64_t gpa = le64_to_cpu(req->u.plug.addr); + const uint16_t nb_blocks = le16_to_cpu(req->u.plug.nb_blocks); + uint16_t type; + + type = virtio_mem_state_change_request(vmem, gpa, nb_blocks, true); + virtio_mem_send_response_simple(vmem, elem, type); +} + +static void virtio_mem_unplug_request(VirtIOMEM *vmem, VirtQueueElement *elem, + struct virtio_mem_req *req) +{ + const uint64_t gpa = le64_to_cpu(req->u.unplug.addr); + const uint16_t nb_blocks = le16_to_cpu(req->u.unplug.nb_blocks); + uint16_t type; + + type = virtio_mem_state_change_request(vmem, gpa, nb_blocks, false); + virtio_mem_send_response_simple(vmem, elem, type); +} + +static void virtio_mem_resize_usable_region(VirtIOMEM *vmem, + uint64_t requested_size, + bool can_shrink) +{ + uint64_t newsize = MIN(memory_region_size(&vmem->memdev->mr), + requested_size + VIRTIO_MEM_USABLE_EXTENT); + + if (!requested_size) { + newsize = 0; + } + + if (newsize < vmem->usable_region_size && !can_shrink) { + return; + } + + vmem->usable_region_size = newsize; +} + +static int virtio_mem_unplug_all(VirtIOMEM *vmem) +{ + RAMBlock *rb = vmem->memdev->mr.ram_block; + int ret; + + if (virtio_mem_is_busy()) { + return -EBUSY; + } + + ret = ram_block_discard_range(rb, 0, qemu_ram_get_used_length(rb)); + if (ret) { + error_report("Unexpected error discarding RAM: %s", strerror(-ret)); + return -EBUSY; + } + bitmap_clear(vmem->bitmap, 0, vmem->bitmap_size); + vmem->size = 0; + + virtio_mem_resize_usable_region(vmem, vmem->requested_size, true); + return 0; +} + +static void virtio_mem_unplug_all_request(VirtIOMEM *vmem, + VirtQueueElement *elem) +{ + if (virtio_mem_unplug_all(vmem)) { + virtio_mem_send_response_simple(vmem, elem, VIRTIO_MEM_RESP_BUSY); + } else { + virtio_mem_send_response_simple(vmem, elem, VIRTIO_MEM_RESP_ACK); + } +} + +static void virtio_mem_state_request(VirtIOMEM *vmem, VirtQueueElement *elem, + struct virtio_mem_req *req) +{ + const uint16_t nb_blocks = le16_to_cpu(req->u.state.nb_blocks); + const uint64_t gpa = le64_to_cpu(req->u.state.addr); + const uint64_t size = nb_blocks * vmem->block_size; + struct virtio_mem_resp resp = { + .type = cpu_to_le16(VIRTIO_MEM_RESP_ACK), + }; + + if (!virtio_mem_valid_range(vmem, gpa, size)) { + virtio_mem_send_response_simple(vmem, elem, VIRTIO_MEM_RESP_ERROR); + return; + } + + if (virtio_mem_test_bitmap(vmem, gpa, size, true)) { + resp.u.state.state = cpu_to_le16(VIRTIO_MEM_STATE_PLUGGED); + } else if (virtio_mem_test_bitmap(vmem, gpa, size, false)) { + resp.u.state.state = cpu_to_le16(VIRTIO_MEM_STATE_UNPLUGGED); + } else { + resp.u.state.state = cpu_to_le16(VIRTIO_MEM_STATE_MIXED); + } + virtio_mem_send_response(vmem, elem, &resp); +} + +static void virtio_mem_handle_request(VirtIODevice *vdev, VirtQueue *vq) +{ + const int len = sizeof(struct virtio_mem_req); + VirtIOMEM *vmem = VIRTIO_MEM(vdev); + VirtQueueElement *elem; + struct virtio_mem_req req; + uint16_t type; + + while (true) { + elem = virtqueue_pop(vq, sizeof(VirtQueueElement)); + if (!elem) { + return; + } + + if (iov_to_buf(elem->out_sg, elem->out_num, 0, &req, len) < len) { + virtio_error(vdev, "virtio-mem protocol violation: invalid request" + " size: %d", len); + g_free(elem); + return; + } + + if (iov_size(elem->in_sg, elem->in_num) < + sizeof(struct virtio_mem_resp)) { + virtio_error(vdev, "virtio-mem protocol violation: not enough space" + " for response: %zu", + iov_size(elem->in_sg, elem->in_num)); + g_free(elem); + return; + } + + type = le16_to_cpu(req.type); + switch (type) { + case VIRTIO_MEM_REQ_PLUG: + virtio_mem_plug_request(vmem, elem, &req); + break; + case VIRTIO_MEM_REQ_UNPLUG: + virtio_mem_unplug_request(vmem, elem, &req); + break; + case VIRTIO_MEM_REQ_UNPLUG_ALL: + virtio_mem_unplug_all_request(vmem, elem); + break; + case VIRTIO_MEM_REQ_STATE: + virtio_mem_state_request(vmem, elem, &req); + break; + default: + virtio_error(vdev, "virtio-mem protocol violation: unknown request" + " type: %d", type); + g_free(elem); + return; + } + + g_free(elem); + } +} + +static void virtio_mem_get_config(VirtIODevice *vdev, uint8_t *config_data) +{ + VirtIOMEM *vmem = VIRTIO_MEM(vdev); + struct virtio_mem_config *config = (void *) config_data; + + config->block_size = cpu_to_le64(vmem->block_size); + config->node_id = cpu_to_le16(vmem->node); + config->requested_size = cpu_to_le64(vmem->requested_size); + config->plugged_size = cpu_to_le64(vmem->size); + config->addr = cpu_to_le64(vmem->addr); + config->region_size = cpu_to_le64(memory_region_size(&vmem->memdev->mr)); + config->usable_region_size = cpu_to_le64(vmem->usable_region_size); +} + +static uint64_t virtio_mem_get_features(VirtIODevice *vdev, uint64_t features, + Error **errp) +{ + MachineState *ms = MACHINE(qdev_get_machine()); + + if (ms->numa_state) { +#if defined(CONFIG_ACPI) + virtio_add_feature(&features, VIRTIO_MEM_F_ACPI_PXM); +#endif + } + return features; +} + +static void virtio_mem_system_reset(void *opaque) +{ + VirtIOMEM *vmem = VIRTIO_MEM(opaque); + + /* + * During usual resets, we will unplug all memory and shrink the usable + * region size. This is, however, not possible in all scenarios. Then, + * the guest has to deal with this manually (VIRTIO_MEM_REQ_UNPLUG_ALL). + */ + virtio_mem_unplug_all(vmem); +} + +static void virtio_mem_device_realize(DeviceState *dev, Error **errp) +{ + MachineState *ms = MACHINE(qdev_get_machine()); + int nb_numa_nodes = ms->numa_state ? ms->numa_state->num_nodes : 0; + VirtIODevice *vdev = VIRTIO_DEVICE(dev); + VirtIOMEM *vmem = VIRTIO_MEM(dev); + uint64_t page_size; + RAMBlock *rb; + int ret; + + if (!vmem->memdev) { + error_setg(errp, "'%s' property is not set", VIRTIO_MEM_MEMDEV_PROP); + return; + } else if (host_memory_backend_is_mapped(vmem->memdev)) { + char *path = object_get_canonical_path_component(OBJECT(vmem->memdev)); + + error_setg(errp, "'%s' property specifies a busy memdev: %s", + VIRTIO_MEM_MEMDEV_PROP, path); + g_free(path); + return; + } else if (!memory_region_is_ram(&vmem->memdev->mr) || + memory_region_is_rom(&vmem->memdev->mr) || + !vmem->memdev->mr.ram_block) { + error_setg(errp, "'%s' property specifies an unsupported memdev", + VIRTIO_MEM_MEMDEV_PROP); + return; + } + + if ((nb_numa_nodes && vmem->node >= nb_numa_nodes) || + (!nb_numa_nodes && vmem->node)) { + error_setg(errp, "'%s' property has value '%" PRIu32 "', which exceeds" + "the number of numa nodes: %d", VIRTIO_MEM_NODE_PROP, + vmem->node, nb_numa_nodes ? nb_numa_nodes : 1); + return; + } + + if (enable_mlock) { + error_setg(errp, "Incompatible with mlock"); + return; + } + + rb = vmem->memdev->mr.ram_block; + page_size = qemu_ram_pagesize(rb); + + if (vmem->block_size < page_size) { + error_setg(errp, "'%s' property has to be at least the page size (0x%" + PRIx64 ")", VIRTIO_MEM_BLOCK_SIZE_PROP, page_size); + return; + } else if (!QEMU_IS_ALIGNED(vmem->requested_size, vmem->block_size)) { + error_setg(errp, "'%s' property has to be multiples of '%s' (0x%" PRIx64 + ")", VIRTIO_MEM_REQUESTED_SIZE_PROP, + VIRTIO_MEM_BLOCK_SIZE_PROP, vmem->block_size); + return; + } else if (!QEMU_IS_ALIGNED(memory_region_size(&vmem->memdev->mr), + vmem->block_size)) { + error_setg(errp, "'%s' property memdev size has to be multiples of" + "'%s' (0x%" PRIx64 ")", VIRTIO_MEM_MEMDEV_PROP, + VIRTIO_MEM_BLOCK_SIZE_PROP, vmem->block_size); + return; + } + + if (ram_block_discard_require(true)) { + error_setg(errp, "Discarding RAM is disabled"); + return; + } + + ret = ram_block_discard_range(rb, 0, qemu_ram_get_used_length(rb)); + if (ret) { + error_setg_errno(errp, -ret, "Unexpected error discarding RAM"); + ram_block_discard_require(false); + return; + } + + virtio_mem_resize_usable_region(vmem, vmem->requested_size, true); + + vmem->bitmap_size = memory_region_size(&vmem->memdev->mr) / + vmem->block_size; + vmem->bitmap = bitmap_new(vmem->bitmap_size); + + virtio_init(vdev, TYPE_VIRTIO_MEM, VIRTIO_ID_MEM, + sizeof(struct virtio_mem_config)); + vmem->vq = virtio_add_queue(vdev, 128, virtio_mem_handle_request); + + host_memory_backend_set_mapped(vmem->memdev, true); + vmstate_register_ram(&vmem->memdev->mr, DEVICE(vmem)); + qemu_register_reset(virtio_mem_system_reset, vmem); +} + +static void virtio_mem_device_unrealize(DeviceState *dev) +{ + VirtIODevice *vdev = VIRTIO_DEVICE(dev); + VirtIOMEM *vmem = VIRTIO_MEM(dev); + + qemu_unregister_reset(virtio_mem_system_reset, vmem); + vmstate_unregister_ram(&vmem->memdev->mr, DEVICE(vmem)); + host_memory_backend_set_mapped(vmem->memdev, false); + virtio_del_queue(vdev, 0); + virtio_cleanup(vdev); + g_free(vmem->bitmap); + ram_block_discard_require(false); +} + +static int virtio_mem_restore_unplugged(VirtIOMEM *vmem) +{ + RAMBlock *rb = vmem->memdev->mr.ram_block; + unsigned long first_zero_bit, last_zero_bit; + uint64_t offset, length; + int ret; + + /* Find consecutive unplugged blocks and discard the consecutive range. */ + first_zero_bit = find_first_zero_bit(vmem->bitmap, vmem->bitmap_size); + while (first_zero_bit < vmem->bitmap_size) { + offset = first_zero_bit * vmem->block_size; + last_zero_bit = find_next_bit(vmem->bitmap, vmem->bitmap_size, + first_zero_bit + 1) - 1; + length = (last_zero_bit - first_zero_bit + 1) * vmem->block_size; + + ret = ram_block_discard_range(rb, offset, length); + if (ret) { + error_report("Unexpected error discarding RAM: %s", + strerror(-ret)); + return -EINVAL; + } + first_zero_bit = find_next_zero_bit(vmem->bitmap, vmem->bitmap_size, + last_zero_bit + 2); + } + return 0; +} + +static int virtio_mem_post_load(void *opaque, int version_id) +{ + if (migration_in_incoming_postcopy()) { + return 0; + } + + return virtio_mem_restore_unplugged(VIRTIO_MEM(opaque)); +} + +static const VMStateDescription vmstate_virtio_mem_device = { + .name = "virtio-mem-device", + .minimum_version_id = 1, + .version_id = 1, + .post_load = virtio_mem_post_load, + .fields = (VMStateField[]) { + VMSTATE_UINT64(usable_region_size, VirtIOMEM), + VMSTATE_UINT64(size, VirtIOMEM), + VMSTATE_UINT64(requested_size, VirtIOMEM), + VMSTATE_BITMAP(bitmap, VirtIOMEM, 0, bitmap_size), + VMSTATE_END_OF_LIST() + }, +}; + +static const VMStateDescription vmstate_virtio_mem = { + .name = "virtio-mem", + .minimum_version_id = 1, + .version_id = 1, + .fields = (VMStateField[]) { + VMSTATE_VIRTIO_DEVICE, + VMSTATE_END_OF_LIST() + }, +}; + +static void virtio_mem_fill_device_info(const VirtIOMEM *vmem, + VirtioMEMDeviceInfo *vi) +{ + vi->memaddr = vmem->addr; + vi->node = vmem->node; + vi->requested_size = vmem->requested_size; + vi->size = vmem->size; + vi->max_size = memory_region_size(&vmem->memdev->mr); + vi->block_size = vmem->block_size; + vi->memdev = object_get_canonical_path(OBJECT(vmem->memdev)); +} + +static MemoryRegion *virtio_mem_get_memory_region(VirtIOMEM *vmem, Error **errp) +{ + if (!vmem->memdev) { + error_setg(errp, "'%s' property must be set", VIRTIO_MEM_MEMDEV_PROP); + return NULL; + } + + return &vmem->memdev->mr; +} + +static void virtio_mem_get_size(Object *obj, Visitor *v, const char *name, + void *opaque, Error **errp) +{ + const VirtIOMEM *vmem = VIRTIO_MEM(obj); + uint64_t value = vmem->size; + + visit_type_size(v, name, &value, errp); +} + +static void virtio_mem_get_requested_size(Object *obj, Visitor *v, + const char *name, void *opaque, + Error **errp) +{ + const VirtIOMEM *vmem = VIRTIO_MEM(obj); + uint64_t value = vmem->requested_size; + + visit_type_size(v, name, &value, errp); +} + +static void virtio_mem_set_requested_size(Object *obj, Visitor *v, + const char *name, void *opaque, + Error **errp) +{ + VirtIOMEM *vmem = VIRTIO_MEM(obj); + Error *err = NULL; + uint64_t value; + + visit_type_size(v, name, &value, &err); + if (err) { + error_propagate(errp, err); + return; + } + + /* + * The block size and memory backend are not fixed until the device was + * realized. realize() will verify these properties then. + */ + if (DEVICE(obj)->realized) { + if (!QEMU_IS_ALIGNED(value, vmem->block_size)) { + error_setg(errp, "'%s' has to be multiples of '%s' (0x%" PRIx64 + ")", name, VIRTIO_MEM_BLOCK_SIZE_PROP, + vmem->block_size); + return; + } else if (value > memory_region_size(&vmem->memdev->mr)) { + error_setg(errp, "'%s' cannot exceed the memory backend size" + "(0x%" PRIx64 ")", name, + memory_region_size(&vmem->memdev->mr)); + return; + } + + if (value != vmem->requested_size) { + virtio_mem_resize_usable_region(vmem, value, false); + vmem->requested_size = value; + } + /* + * Trigger a config update so the guest gets notified. We trigger + * even if the size didn't change (especially helpful for debugging). + */ + virtio_notify_config(VIRTIO_DEVICE(vmem)); + } else { + vmem->requested_size = value; + } +} + +static void virtio_mem_get_block_size(Object *obj, Visitor *v, const char *name, + void *opaque, Error **errp) +{ + const VirtIOMEM *vmem = VIRTIO_MEM(obj); + uint64_t value = vmem->block_size; + + visit_type_size(v, name, &value, errp); +} + +static void virtio_mem_set_block_size(Object *obj, Visitor *v, const char *name, + void *opaque, Error **errp) +{ + VirtIOMEM *vmem = VIRTIO_MEM(obj); + Error *err = NULL; + uint64_t value; + + if (DEVICE(obj)->realized) { + error_setg(errp, "'%s' cannot be changed", name); + return; + } + + visit_type_size(v, name, &value, &err); + if (err) { + error_propagate(errp, err); + return; + } + + if (value < VIRTIO_MEM_MIN_BLOCK_SIZE) { + error_setg(errp, "'%s' property has to be at least 0x%" PRIx32, name, + VIRTIO_MEM_MIN_BLOCK_SIZE); + return; + } else if (!is_power_of_2(value)) { + error_setg(errp, "'%s' property has to be a power of two", name); + return; + } + vmem->block_size = value; +} + +static void virtio_mem_instance_init(Object *obj) +{ + VirtIOMEM *vmem = VIRTIO_MEM(obj); + + vmem->block_size = VIRTIO_MEM_MIN_BLOCK_SIZE; + + object_property_add(obj, VIRTIO_MEM_SIZE_PROP, "size", virtio_mem_get_size, + NULL, NULL, NULL); + object_property_add(obj, VIRTIO_MEM_REQUESTED_SIZE_PROP, "size", + virtio_mem_get_requested_size, + virtio_mem_set_requested_size, NULL, NULL); + object_property_add(obj, VIRTIO_MEM_BLOCK_SIZE_PROP, "size", + virtio_mem_get_block_size, virtio_mem_set_block_size, + NULL, NULL); +} + +static Property virtio_mem_properties[] = { + DEFINE_PROP_UINT64(VIRTIO_MEM_ADDR_PROP, VirtIOMEM, addr, 0), + DEFINE_PROP_UINT32(VIRTIO_MEM_NODE_PROP, VirtIOMEM, node, 0), + DEFINE_PROP_LINK(VIRTIO_MEM_MEMDEV_PROP, VirtIOMEM, memdev, + TYPE_MEMORY_BACKEND, HostMemoryBackend *), + DEFINE_PROP_END_OF_LIST(), +}; + +static void virtio_mem_class_init(ObjectClass *klass, void *data) +{ + DeviceClass *dc = DEVICE_CLASS(klass); + VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass); + VirtIOMEMClass *vmc = VIRTIO_MEM_CLASS(klass); + + device_class_set_props(dc, virtio_mem_properties); + dc->vmsd = &vmstate_virtio_mem; + + set_bit(DEVICE_CATEGORY_MISC, dc->categories); + vdc->realize = virtio_mem_device_realize; + vdc->unrealize = virtio_mem_device_unrealize; + vdc->get_config = virtio_mem_get_config; + vdc->get_features = virtio_mem_get_features; + vdc->vmsd = &vmstate_virtio_mem_device; + + vmc->fill_device_info = virtio_mem_fill_device_info; + vmc->get_memory_region = virtio_mem_get_memory_region; +} + +static const TypeInfo virtio_mem_info = { + .name = TYPE_VIRTIO_MEM, + .parent = TYPE_VIRTIO_DEVICE, + .instance_size = sizeof(VirtIOMEM), + .instance_init = virtio_mem_instance_init, + .class_init = virtio_mem_class_init, + .class_size = sizeof(VirtIOMEMClass), +}; + +static void virtio_register_types(void) +{ + type_register_static(&virtio_mem_info); +} + +type_init(virtio_register_types) diff --git a/hw/virtio/Kconfig b/hw/virtio/Kconfig index 83122424fa..0eda25c4e1 100644 --- a/hw/virtio/Kconfig +++ b/hw/virtio/Kconfig @@ -47,3 +47,14 @@ config VIRTIO_PMEM depends on VIRTIO depends on VIRTIO_PMEM_SUPPORTED select MEM_DEVICE + +config VIRTIO_MEM_SUPPORTED + bool + +config VIRTIO_MEM + bool + default y + depends on VIRTIO + depends on LINUX + depends on VIRTIO_MEM_SUPPORTED + select MEM_DEVICE diff --git a/hw/virtio/Makefile.objs b/hw/virtio/Makefile.objs index 13e75f171f..f3a65e01b7 100644 --- a/hw/virtio/Makefile.objs +++ b/hw/virtio/Makefile.objs @@ -19,6 +19,7 @@ obj-$(call land,$(CONFIG_VHOST_USER_FS),$(CONFIG_VIRTIO_PCI)) += vhost-user-fs-p obj-$(CONFIG_VIRTIO_IOMMU) += virtio-iommu.o obj-$(CONFIG_VHOST_VSOCK) += vhost-vsock-common.o vhost-vsock.o obj-$(CONFIG_VHOST_USER_VSOCK) += vhost-vsock-common.o vhost-user-vsock.o +obj-$(CONFIG_VIRTIO_MEM) += virtio-mem.o ifeq ($(CONFIG_VIRTIO_PCI),y) obj-$(CONFIG_VHOST_VSOCK) += vhost-vsock-pci.o