projects / qemu.git / blame
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|---|---|---|
| 639090d8 EU |
1 | Multi-process QEMU |
| 2 | ================== | |
| 3 | ||
| 4 | This document describes how to configure and use multi-process qemu. | |
| 5 | For the design document refer to docs/devel/qemu-multiprocess. | |
| 6 | ||
| 7 | 1) Configuration | |
| 8 | ---------------- | |
| 9 | ||
| 10 | multi-process is enabled by default for targets that enable KVM | |
| 11 | ||
| 12 | ||
| 13 | 2) Usage | |
| 14 | -------- | |
| 15 | ||
| 16 | Multi-process QEMU requires an orchestrator to launch. | |
| 17 | ||
| 18 | Following is a description of command-line used to launch mpqemu. | |
| 19 | ||
| 20 | * Orchestrator: | |
| 21 | ||
| 22 | - The Orchestrator creates a unix socketpair | |
| 23 | ||
| 24 | - It launches the remote process and passes one of the | |
| 25 | sockets to it via command-line. | |
| 26 | ||
| 27 | - It then launches QEMU and specifies the other socket as an option | |
| 28 | to the Proxy device object | |
| 29 | ||
| 30 | * Remote Process: | |
| 31 | ||
| 32 | - QEMU can enter remote process mode by using the "remote" machine | |
| 33 | option. | |
| 34 | ||
| 35 | - The orchestrator creates a "remote-object" with details about | |
| 36 | the device and the file descriptor for the device | |
| 37 | ||
| 38 | - The remaining options are no different from how one launches QEMU with | |
| 39 | devices. | |
| 40 | ||
| 41 | - Example command-line for the remote process is as follows: | |
| 42 | ||
| 43 | /usr/bin/qemu-system-x86_64 \ | |
| 44 | -machine x-remote \ | |
| 45 | -device lsi53c895a,id=lsi0 \ | |
| 46 | -drive id=drive_image2,file=/build/ol7-nvme-test-1.qcow2 \ | |
| 47 | -device scsi-hd,id=drive2,drive=drive_image2,bus=lsi0.0,scsi-id=0 \ | |
| 45b09cb1 | 48 | -object x-remote-object,id=robj1,devid=lsi0,fd=4, |
| 639090d8 EU |
49 | |
| 50 | * QEMU: | |
| 51 | ||
| 52 | - Since parts of the RAM are shared between QEMU & remote process, a | |
| 53 | memory-backend-memfd is required to facilitate this, as follows: | |
| 54 | ||
| 55 | -object memory-backend-memfd,id=mem,size=2G | |
| 56 | ||
| 57 | - A "x-pci-proxy-dev" device is created for each of the PCI devices emulated | |
| 58 | in the remote process. A "socket" sub-option specifies the other end of | |
| 59 | unix channel created by orchestrator. The "id" sub-option must be specified | |
| 60 | and should be the same as the "id" specified for the remote PCI device | |
| 61 | ||
| 62 | - Example commandline for QEMU is as follows: | |
| 63 | ||
| 64 | -device x-pci-proxy-dev,id=lsi0,socket=3 |