[Qemu-devel] Inter Shared Memory ( Ivshmem ) : Cannot Bind

[Qemu-devel] Inter Shared Memory ( Ivshmem ) : Cannot Bind

[Rogue S.T]

Hello, friends.
I encounter a problem when i use ivshmem with my guest, my ivshmem server is not start, and output a error : Example code, do not use in production ,cannot bind.


Detail distribution: 
Today, I know ivshmem from a topic "QEMU version 2.10.93 User Documentation", 
Ivshmem: it can create a shared memory that guest device use, so we can use this memory to do something ourselves.
First, I create host memory backend:
     -object memory-backend-file,size=1M,share,mem-path=/dev/shm/ivshmem,id=hostmem
Twice, Bind a shared memory device to my guest:
    -device ivshmem-plain,memdev=hostmem
Then I boot ivshmem servi
    ivshmem-server -p /var/run/ivshmem-server.pid  -S /tmp/ivshmem_socket  -M ivshmem -m /dev/shm -l 1M -n 2
Next time i get this error:
    *** Example code, do not use in production ***
    cannot bind
And i search the problem on google, but nothing to get, hope you can help me solve it.
following message is my host environment:
    host:  ubuntu 1604
    qemu:  version 2.10.90 (v2.11.0-rc0-dirty)
    libvirt:  libvirtd (libvirt) 3.9.0
    guest:    window 7 professor


Refer:
    https://qemu.weilnetz.de/doc/qemu-doc.html#Inter_002dVM-Shared-Memory-device (topic qemu documention)
    https://helpmanual.io/help/ivshmem-server/  ( how to use ivshmem-server )

Re: [Qemu-devel] [libvirt-users] Inter Shared Memory ( Ivshmem ) : Cannot Bind

[Martin Kletzander]

On Mon, Dec 11, 2017 at 03:03:34PM +0800, Rogue S.T wrote:
>Hello, friends.
>I encounter a problem when i use ivshmem with my guest, my ivshmem server is not start, and output a error : Example code, do not use in production ,cannot bind.
>
>
>Detail distribution:
>Today, I know ivshmem from a topic "QEMU version 2.10.93 User Documentation",
>Ivshmem: it can create a shared memory that guest device use, so we can use this memory to do something ourselves.
>First, I create host memory backend:
>     -object memory-backend-file,size=1M,share,mem-path=/dev/shm/ivshmem,id=hostmem
>Twice, Bind a shared memory device to my guest:
>    -device ivshmem-plain,memdev=hostmem

You are using plain, but

>Then I boot ivshmem servi
>    ivshmem-server -p /var/run/ivshmem-server.pid  -S /tmp/ivshmem_socket  -M ivshmem -m /dev/shm -l 1M -n 2

You are running a server.  This is not how it works.

Looks like you are playing with something that you don't really need, otherwise
you would do things differetly.  It you are just trying it out, that's fine.
Otherwise make sure it's what you need.  More information on how this hot mess
works is here:

https://git.qemu.org/?p=qemu.git;a=blob;f=docs/specs/ivshmem-spec.txt

>Next time i get this error:
>    *** Example code, do not use in production ***
>    cannot bind
>And i search the problem on google, but nothing to get, hope you can help me solve it.
>following message is my host environment:
>    host:  ubuntu 1604
>    qemu:  version 2.10.90 (v2.11.0-rc0-dirty)
>    libvirt:  libvirtd (libvirt) 3.9.0
>    guest:    window 7 professor
>
>
>Refer:
>    https://qemu.weilnetz.de/doc/qemu-doc.html#Inter_002dVM-Shared-Memory-device (topic qemu documention)
>    https://helpmanual.io/help/ivshmem-server/  ( how to use ivshmem-server )

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