[Qemu-discuss] Antw: qemu-kvm and qemu-system-x86_64

[Steffen Weißgerber]

Hi,

maybe you want this in general, not only for qemu.

Then use Gentoo Linux. There buliding from source is the standard way to 
install applications.

On a running system a 'emerge qemu' does the job. And so called use flags 
control the features
you want to compiled in.

================================================
address@hidden ~ $ sudo emerge -avt qemu
Passwort:

 * IMPORTANT: 4 news items need reading for repository 'gentoo'.
 * Use eselect news read to view new items.


These are the packages that would be merged, in reverse order:

Calculating dependencies... done!
[ebuild   R    ] app-emulation/qemu-2.11.0::gentoo  USE="aio bzip2 caps curl 
fdt filecaps jpeg ncurses nls pin-upstream-blobs png rbd seccomp spice tci 
vhost-net vnc xattr -accessibility -alsa -bluetooth -debug (-glusterfs) -gnutls 
-gtk -gtk2 -infiniband -iscsi -lzo -nfs -numa -opengl -pulseaudio -python -sasl 
-sdl -sdl2 (-selinux) -smartcard -snappy -ssh -static -static-user -systemtap 
{-test} -usb -usbredir -vde -virgl -virtfs -vte -xen -xfs" 
PYTHON_TARGETS="python2_7" QEMU_SOFTMMU_TARGETS="x86_64 -aarch64 -alpha -arm 
-cris -i386 -lm32 -m68k -microblaze -microblazeel -mips -mips64 -mips64el 
-mipsel -moxie -nios2 -or1k -ppc -ppc64 -ppcemb -s390x -sh4 -sh4eb -sparc 
-sparc64 -tricore -unicore32 -xtensa -xtensaeb" QEMU_USER_TARGETS="x86_64 
-aarch64 -alpha -arm -armeb -cris -hppa -i386 -m68k -microblaze -microblazeel 
-mips -mips64 -mips64el -mipsel -mipsn32 -mipsn32el -nios2 -or1k -ppc -ppc64 
-ppc64abi32 -ppc64le -s390x -sh4 -sh4eb -sparc -sparc32plus -sparc64 -tilegx" 0 
KiB

Total: 1 package (1 reinstall), Size of downloads: 0 KiB

Would you like to merge these packages? [Yes/No]
================================================

We run a multinode (6 at the moment) qemu cluster for years with around 100 
vm's.

And compiling on a large cpu's with tmp (/var/tmp/portage for compiling) in RAM 
(tmpfs) is funny
and rocks the machines.

Regards

Steffen


>>> "Deneau, Tom" <address@hidden> 22.03.2018 18:29 >>>
My situation: I want to run a KVM-accelerated qemu but I want to build 
everything involved from the latest sources and use those instead of any 
downloadable distro packages.  (This is on SLES12-SP3 although I don't think 
the distro matters).

I am able to build and install from 
   * http://github.com/qemu/qemu using  ../configure 
--target-list=x86_64-softmmu --enable-kvm --prefix=/usr --sysconfdir=/etc
   * http://github.com/libvirt/libvirt  using ./configure --prefix=/usr 
--sysconfdir=/etc --localstatedir=/var

Before running make install,  I also removed the existing distro packages like 
libvirt, libvirt-client, qemu-kvm, etc.

My  question:  In the installed distro packages there was an executable, 
/usr/libexec/qemu-kvm
But after building and installing qemu from sources as above, I did not see any 
new qemu-kvm.
Is there some other repository I need to build from to get qemu-kvm? 

I ask because I am starting vms using virsh define xyz.xml; virsh start xyz.  
And in the original .xml files I had the following under devices:
       <emulator>/usr/libexec/qemu-kvm</emulator>

Can I replace that with 
   <emulator>/usr/local/bin/qemu-system-x86_64</emulator>

And given that I am already using
    <os>
        <type>hvm</type>
        <boot dev="hd"></boot>
    </os>

Will I get the same KVM acceleration as I was previously getting by using 
qemu-kvm?

-- Tom Deneau





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