A new memory backend, the shared memory backend, based on the file memory backend.
This new backend allows a master QEMU instance to share a part of his main memory whith a slave QEMU instance. It is then possible to load a firmware on this memory and trigger the slave boot using a SDM signal. Such new backend enables, on a master side, to allocate the whole memory as shareable (e.g. /dev/shm, or hugetlbfs). On the slave side it enables the startup of QEMU without any main memory allocated. Then the slave goes in a waiting state, the same used in the case of an incoming migration, and the file descriptor of the shared memory is sent by the master over a socket. The waiting state ends when the master sends to the slave a signal with size and offset to mmap and use as memory as payload. You can test those patches using modules and test application available on https://git.virtualopensystems.com/dev/qemu-het-tools. - SDM Platform module on branch sdm_test_mod_v1 - Test application on branch sdm_test_app - Slave files on branch demo_slaves_sdm QEMU code is avalaible here https://git.virtualopensystems.com/dev/qemu on branch rfc_v2. Run QEMU master instance: ./qemu-system-arm -nographic \ -kernel zImage \ -M virt -m 1G \ -initrd busybox.cpio \ -object multi-socket-backend,id=sock,path=sock,listen \ -object memory-backend-shared,id=mem,size=1G,mem-path=/dev/hugepages,socket=sock,master \ -object sdm-signal-shboot,id=boot,shm=mem \ -object sdm-communication-socket,id=scomm,socket=sock \ -device virtio-sdm-device,comm=scomm,master,num-slaves=1,len-signals=1,signals[0]=boot \ -append "mem=512M memmap=512M$0x60000000" \ -numa node,memdev=mem -m 1G Run QEMU slave instance: ./qemu-system-arm -nographic \ -kernel zImage \ -M virt -m 1G \ -initrd busybox.cpio \ -object multi-socket-backend,id=sock,path=sock \ -object memory-backend-shared,id=mem,size=512M,socket=sock \ -object sdm-signal-shboot,id=boot,shm=mem \ -object sdm-communication-socket,id=scomm,socket=sock \ -device sdm-platform,comm=scomm,len-signals=1,signals[0]="boot" \ -incoming "shared:mem" \ -numa node,memdev=mem -m 512M On the master, load the SDM module (insmod sdm_test_mod_v1) and trigger the boot with the following command: ./sdm-test -b 0 1 zImage slave.dtb zImage and slave.dtb are available on branch demo_slaves_sdm. This patch serie is a follow-up to "[RFC PATCH 0/8] Towards an Heterogeneous QEMU": https://lists.gnu.org/archive/html/qemu-devel/2015-10/msg00171.html This patch serie depends on: - [RFC v2 0/6] SDM Interface - [RFC v2 1/1] backend: multi-client-socket This work has been sponsored by Huawei Technologies Duesseldorf GmbH. Baptiste Reynal (3): backend: shared memory backend migration: add shared migration type hw/misc: sdm signal shboot Christian Pinto (3): qemu: slave machine flag hw/arm: boot qemu: numa backends/Makefile.objs | 2 +- backends/hostmem-shared.c | 198 ++++++++++++++++++++++++++++++++++++ hw/arm/boot.c | 13 +++ hw/core/machine.c | 27 +++++ hw/misc/Makefile.objs | 1 + hw/misc/sdm-signal-shboot.c | 62 +++++++++++ include/hw/boards.h | 2 + include/hw/misc/sdm-signal-shboot.h | 38 +++++++ include/migration/migration.h | 2 + include/sysemu/hostmem-shared.h | 66 ++++++++++++ migration/Makefile.objs | 2 +- migration/migration.c | 2 + migration/shared.c | 33 ++++++ numa.c | 17 +++- qemu-options.hx | 5 +- util/qemu-config.c | 5 + 16 files changed, 471 insertions(+), 4 deletions(-) create mode 100644 backends/hostmem-shared.c create mode 100644 hw/misc/sdm-signal-shboot.c create mode 100644 include/hw/misc/sdm-signal-shboot.h create mode 100644 include/sysemu/hostmem-shared.h create mode 100644 migration/shared.c -- 2.7.3
