Re: How to create and start Xen guest VM by qemu-system-x86_64 command line

[Alex Bennée <alex.bennee@xxxxxxxxxx>]

Trigger Huang <trigger.huang@xxxxxxxxx> writes:

> Hello,
>
> I have built & installed Xen 4.15 onto my Ubuntu20.04 platform successfully 
> according to
> https://wiki.xenproject.org/wiki/Compiling_Xen_From_Source 
> After reboot, I entered Domain 0 successfully. The command xl info shows the 
> right version string.
> host                   : xvg
> release                : 5.13.0-30-generic
> version                : #33~20.04.1-Ubuntu SMP Mon Feb 7 14:25:10 UTC 2022
> machine                : x86_64
> nr_cpus                : 16
> max_cpu_id             : 31
> nr_nodes               : 1
> cores_per_socket       : 8
> threads_per_core       : 2
> cpu_mhz                : 2994.377
> hw_caps                : 
> 178bf3ff:76d8320b:2e500800:244037ff:0000000f:219c91a9:00400004:00000500
> virt_caps              : pv hvm hvm_directio pv_directio hap shadow
> total_memory           : 15719
> free_memory            : 11425
> sharing_freed_memory   : 0
> sharing_used_memory    : 0
> outstanding_claims     : 0
> free_cpus              : 0
> xen_major              : 4
> xen_minor              : 15
> xen_extra              : .3-pre-atg08
> xen_version            : 4.15.3-pre-atg08
> xen_caps               : xen-3.0-x86_64 hvm-3.0-x86_32 hvm-3.0-x86_32p 
> hvm-3.0-x86_64
> xen_scheduler          : credit2
> xen_pagesize           : 4096
> platform_params        : virt_start=0xffff800000000000
> xen_changeset          : Fri Mar 4 13:33:49 2022 +0800 git:6aa4cdbc31
> xen_commandline        : placeholder dom0_mem=4096M,max:8192M no-real-mode 
> edd=off
> cc_compiler            : gcc (Ubuntu 9.3.0-17ubuntu1~20.04) 9.3.0
> cc_compile_by          : xvg
> cc_compile_domain      :
> cc_compile_date        : Fri Mar  4 14:21:33 CST 2022
> build_id               : 234929adcb7588b1414c2b6e5477fa95052b4ded
> xend_config_format     : 4
>
> Then my next step is to create ubuntu guest VM(sudo or use root user):
>    /usr/local/lib/xen/bin/qemu-system-x86_64 -smp 1 -xen-domid 4 -machine 
> xenfv -m 4G -net nic,model=virtio -net
> user,hostfwd=tcp::2222-:22 -hda ./u2004.qcow2 -boot d -cdrom 
> ./ubuntu-20.04-desktop-amd64.iso
> However, I always failed with the following error:
>     qemu-system-x86_64: failed to map ioreq server resources: error 3 
> handle=0x55eeb1f6c0b0
>     qemu-system-x86_64: xen hardware virtual machine initialisation failed
> After debugging, the error is caused by osdep_xenforeignmemory_map_resource 
> failed to invoke IOCTL_PRIVCMD_MMAP_RESOURCE. And
> this IOCTL will return -1.

Why are you not launching your guests with the xl commands? 

>
> So my question is, am I using the right qemu command? Anything else is needed 
> to set/config?
> Note, if I didn't specify the option ' -xen-domid 4 -machine xenfv ', I can 
> start qemu successfully
>
> Would you please help with it?


-- 
Alex Bennée