[RFC,v2,35/35] multi-process: add configure and usage information

Commit Message

Elena Ufimtseva June 17, 2019, 6:17 p.m. UTC

From: Elena Ufimtseva <[e-mail]>

Signed-off-by: Elena Ufimtseva <[e-mail]>
Signed-off-by: Jagannathan Raman <[e-mail]>
Signed-off-by: John G Johnson <[e-mail]>
---
 Changes in v2:
 - since the changes were made to use existing device/drive options,
 the document was modified to reflect this.
---
 docs/qemu-multiprocess.txt | 59 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)
 create mode 100644 docs/qemu-multiprocess.txt

Patch

diff --git a/docs/qemu-multiprocess.txt b/docs/qemu-multiprocess.txt
new file mode 100644
index 0000000000..3b11ca9cc2
--- /dev/null
+++ b/docs/qemu-multiprocess.txt
@@ -0,0 +1,59 @@ 
+Multi-process QEMU
+
+This document describes how to configure and use multi-process qemu.
+For the design document refer to docs/devel/qemu-multiprocess.
+
+Configure
+
+To enable support for multi-process add --enable-mpqemu
+to the list of options for configure.
+
+Usage
+
+Command line
+
+To start qemu with devices intended to run in the separate emulation
+process, the following suboptions are used:
+
+ remote, [socket=[socket_number],|command="command to run",] rid="remote process id" 
+For exmaple, for non multi-process qemu:
+    -device lsi53c895a,id=scsi0 device
+    -device scsi-hd,drive=drive0,bus=scsi0.0,scsi-id=0
+    -drive id=drive0,file=data-disk.img
+
+and for multi-process qemu and no libvirt support (i.e. QEMU forks child processes):
+    -device lsi53c895a,id=scsi0,remote,rid=0,command="qemu-scsi-dev"
+    -device scsi-hd,drive=drive0,bus=scsi0.0,scsi-id=0,remote,rid="0",command="qemu-scsi-dev"
+    -drive id=drive0,file=data-disk.img,remote,rid=0,command="qemu-scsi-dev"
+
+
+The memorybackend object has to be specified on the command line:
+-object memory-backend-file,id=mem,mem-path=/dev/shm/,size=4096M,share=on
+
+
+Example of running scsi drive in the guest in separate qemu
+process:
+
+qemu-system-x86_64 -enable-kvm -machine q35 -smp 4 -m 4096M -vnc :0 \
+-net nic -net user,hostfwd=tcp::5022-:22 -hda os.qcow2 \
+-device lsi53c895a,id=scsi0,remote,rid=0,command="qemu-scsi-dev" \
+-device scsi-hd,drive=drive0,bus=scsi0.0,scsi-id=0,remote,rid="0",command="qemu-scsi-dev" \
+-drive id=drive0,file=data-disk.img,remote,rid=0,command="qemu-scsi-dev" \
+-object memory-backend-file,id=mem,mem-path=/dev/shm/,size=4096M,share=on -numa node,memdev=mem
+
+HMP commands
+
+For hotplugging in multi-process qemu the following commands
+can be used:
+
+- rdevice_add;
+- rdevice_del;
+- rdrive_add;
+- rdrive_del;
+- remote_proc_list
+
+After running rescan_scsi_bus.sh -a, guest will be able to identify newly
+added devices.
+
+
+