On Wed, 01/20 22:12, Roy Shterman wrote:
> and nothing happened, can you think of something i'm missing?
The "x-data-plane=on" option used to be the temporary flag and has been removed
since last release of QEMU. In the command line, the syntax to use dataplane
for virtio-blk/scsi is:
-object iothread,id=iothread0 \
-device virtio-{blk,scsi}-pci,iothread=iothread0,$your_usual_opts
In libvirt xml, you need to define "iothread" objects, and assign to devices:
<domain>
...
<iothreads>1</iothreads>
...
<devices>
...
<disk type='file' device='disk'>
<driver name='qemu' type='qcow2' iothread='1'/>
...
</disk>
</devices>
</domain>
I haven't tried virtio-scsi dataplane with libvirt on my own, and I don't know
if it is supported there (note: even though in QEMU it is configurable,
dataplane is not completely thread safe, so be careful).
> second thing, I'm trying to look for the code where QEMU allocate all
> guest memory (2 GB) in my case.
The guest ram is allocated by the machine in the most simple case:
(gdb) bt
#0 memory_region_init_ram (mr=0x55555658d9c0, owner=0x0, name=0x555555b05a6f
"pc.ram", size=4294967296, errp=0x5555564aa770 <error_fatal>) at
/home/fam/work/qemu/memory.c:1226
#1 0x0000555555720f2c in allocate_system_memory_nonnuma (mr=0x55555658d9c0,
owner=0x0, name=0x555555b05a6f "pc.ram", ram_size=4294967296) at
/home/fam/work/qemu/numa.c:434
#2 0x0000555555720f9b in memory_region_allocate_system_memory
(mr=0x55555658d9c0, owner=0x0, name=0x555555b05a6f "pc.ram",
ram_size=4294967296)
at /home/fam/work/qemu/numa.c:447
#3 0x000055555579092d in pc_memory_init (pcms=0x55555652e280,
system_memory=0x555556531280, rom_memory=0x55555658cfd0,
ram_memory=0x7fffffffdce8, guest_info=0x55555658d570)
at /home/fam/work/qemu/hw/i386/pc.c:1307
#4 0x0000555555792f90 in pc_init1 (machine=0x55555652e280,
host_type=0x555555b064f0 "i440FX-pcihost", pci_type=0x555555b064e9 "i440FX")
at /home/fam/work/qemu/hw/i386/pc_piix.c:164
#5 0x00005555557939c2 in pc_init_v2_6 (machine=0x55555652e280) at
/home/fam/work/qemu/hw/i386/pc_piix.c:429
#6 0x000055555583cf24 in main (argc=3, argv=0x7fffffffe1c8,
envp=0x7fffffffe1e8) at /home/fam/work/qemu/vl.c:4511
Fam
