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Virtualization Linux

Kernel-Based Virtual Machine Ported To ARM64 58

hypnosec writes "Linux KVM has been ported to ARM64 just ahead of the release of the architecture, it has been revealed. Just last year ARM KVM virtualization support for Cortex-A15 32bit ARM processor was published. Marc Zyngier of ARM released a set of 29 patches that contained the implementation of KVM for ARM that depends on the pre-arm64 rework as well as tiny perf patch published earlier. Some of the newly released port are support for 4k and 64k pages and 32-bit as well as 64-bit guests."
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Kernel-Based Virtual Machine Ported To ARM64

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  • What's the raison detre for KVM?

    Granted VirtualBox's slot is open-source end-user virt.

    But how about KVM vs. other server-oriented virtualization solutions? Like VMWare, Xen, and OpenVZ?

    What's worked best for you (stability, memory, resources, separation, ease of use, $$), and what plays well with the latest Ubuntu Server LTS?

    • by Anonymous Coward

      I'm using KVM beacause it's open source (unlike VMWare) and when I was setting up a CentOS based cluster it seemed to have the best support for what I wanted to do.
      So far, I'm happy with my choice, but I'm far from an expert.

      • I wanted to ditch VirtualBox in favor of KVM, but ran into a huge stumbling block. I wanted to virtualize my servers, so I need to have KVM's network adapter in bridge mode.

        After following the KVM instructions, which had me manually changing many kernel settings, and a lot of trial and error for several days, I threw my hands up and went back to VirtualBox. I reverted all the kernel settings back to stock values, and I had VirtualBox bridging the network adapters in just a few seconds.

        Getting KVM set up a

        • I wanted to virtualize my servers, so I need to have KVM's network adapter in bridge mode.

          After following the KVM instructions, which had me manually changing many kernel settings, and a lot of trial and error for several days, I threw my hands up and went back to VirtualBox.

          I can't comment on other distros, but setting up a bridge under Centos is very easy. virt-manager even has support built-in to perform this task. You don't need to change anything kernel related (the scripts that manage the interfa

          • virt-manager even has support built-in to perform this task.

            I tried virt-manager under Kubuntu, but it kept dying after just a few mouse clicks. I've since moved all of my virtualization to 64-bit Debian (under VirtualBox), but didn't think to try virt-manager there. When I get some time, I'll try it. Thanks.

        • by Squash ( 2258 )
          Using virt-manager to configure a Host's network interfaces to bridging is pretty straightforward. I've got a 5 node KVM cluster at home home office, running Ubuntu 12.04 LTS, managing them via virt-manager on Ubuntu 12.10. They are all operating in bridge mode. Now, a feature that doesn't quite work as advertised, doing a live migration (without shared storage) requires an extra step that isn't really made clear, you have to create the destination disk image (same size in bytes) before it will migrate.
    • by kwalker ( 1383 ) on Wednesday March 06, 2013 @02:34PM (#43095495) Journal

      VMware is not open-source, and is pretty expensive if you need more than the basics. However it's well-supported in most circles, and its paid-license-support gets it past the PHB hurdle.

      Xen is a beast. The time investment alone to get it to work puts it out of reach for even mid-level Linux admins. Plus it requires extra help to run non-Xen guest OSes.

      OpenVZ isn't real virtualization. It's OS-level containment and pseudo-virtualization, which can be good for some things.

      KVM has real steam behind it. It's already in the mainline kernel, it supports real virtualization (I've been able to get all modern Linux distros running as KVM guests as well as WinXP - WIn8 preview), but can get almost as fast as Xen's para-virtualization with some guest-OS drivers installed. There have been new features added to the Linux kernel to help it (Kernel Same-page Merging is one example). It's not that difficult to get working, especially if you use something like libVirt to do the heavy lifting for you.

      I'm not an Ubuntu user, so I can't give first-hand experience using KVM on LTS, but a quick google search turned up this this HOWTOforge article on the latest LTS [howtoforge.com] and from my reading, it seems pretty straight forward.

      • "VMware is not open-source, and is pretty expensive if you need more than the basics. However it's well-supported in most circles, and its paid-license-support gets it past the PHB hurdle."

        KVM is to VMware what Sendmail is to Exchange, not a drop in replacement in 99% of what people are expecting out a VM product.

        Xen is tainted by its association with Citrix to me, but I wish there would be more support for Virtualbox (also tainted by corporate association, of course) since that is the most n00b friendly vi

    • KVM was introduced as a simpler solution based on leveraging the virtualization hardware in newer x86 hardware. Because it's hardware-only it doesn't have to do as much fixing-up of things behind the scenes, which meant that the code was a lot simpler.

      Because it's open-source it's useful as an initial target for virtualization work within the kernel. The other virtualization solutions can build on a lot of the same kernel functionality but it's harder to see what they're doing because it tends to be more

    • by undeadbill ( 2490070 ) on Wednesday March 06, 2013 @03:14PM (#43095957)

      Well, it depends.

      All of the virtualization platforms out there are essentially based on QEMU. All of them read the QCOW file format. All of them have their own implementation and direction of that initial vision.

      My experience with KVM is that it is focused on Linux and Windows support. There may be less you can configure under the hood with KVM than with Xen, but if you are a windows and linux shop, or just a linux shop, KVM is awesome. KVM is also the ONLY solution I would try to deploy under RHEL or derivatives, as they dropped Xen support in 6.x. Xen support will be back in 7.x, but that is because RHEL's dropping of support for Xen open source pissed off people on the kernel dev team, so they decided to add it to the kernel directly.

      My experience with Xen is that it has a much broader focus, and is more component accessible. The virtual machine hardware and the management tool sets can be easily swapped out for custom ones. I have a number of virtual machine BIOS to pick from if I run into a BIOS bug. I can support BSD and other systems that KVM doesn't, or doesn't do as well. We use Xen as our go to platform, but deployment of KVM would have been faster in some aspects if we didn't need multi-platform support. Xen documentation I've found is also more mature. AFAIK, Xen is the basis for the Amazon EC2 cloud platform (I could be wrong about that). Ubuntu and debian have good support for Xen, but documentation of, say, building a multiple vlan 802.1q networked solution is a situation of YMMV.

      My experience with VMWare is that it is a great pay virtualization environment, provided you are willing to shell out for their recommended hardware as well. Setting up things like live migration and cloning are easier with their GUI and step by step instructions. If your company is going to pay for all of that, then it is definitely something worth taking advantage of, as the learning curve is much more accessible (but, it also means you can shoot yourself in the foot faster as well). But the moving target of licensing and hardware requirements are an issue, and my workplace is migrating away from VMWare to Xen because of those issues. Again, if the will to spend is there, it is just fine. I would only use the free solution as something to learn on.

      Jails and chroots are nice in a single platform environment, because why waste time on overhead? But the downside is that it is single platform. I'd go more into that, but it isn't really relevant to this discussion. What I would really love to see is something new under the BSD's that offered multi-platform guest support as a host.

      All of the the three big players- KVM, XEN, and VMWare are part of OpenStack, so you can use the OpenStack API. If you are ever going to migrate, or have to have cross-compatibility with other virtualization platforms (business parternships can warrant this), then having OpenStack tools available can be really helpful if you want to write the code for it. All three are also supported by OpenNebula, which is an open source pointy clicky interface that can manage all three platforms- provided you can code in your customizations, which could include live migration, etc.

      Certification and education are another factor. VMWare wins that one hands down, as they have web accessible training and an easy certification path. The only way you can easily certify on Xen is to get LPIC-3 certified, which will also certify for KVM. The other option is to take the RHEL series (woah, big dollars!), and get certified at the RH Architect level in KVM. The LPIC route actually costs less than the other two, but there are no classes available at that level. Most businesses are familiar only with the VMWare cert path. Also, most companies that have a strong need for someone to fix their problems don't really care which virt solution one has experience with- they care about having an understanding about how all of them work under the hood so that their structural issues are addressed.

      • by Squash ( 2258 ) on Wednesday March 06, 2013 @07:10PM (#43098681) Homepage
        Xen is indeed the platform on which Amazon ec2 is based, but I would say that decision might be made differently today if given the chance. First off, at the time when it was being created, Xen was the only real option. KVM simply didn't exist until after ec2's launch in 2006, and the only real alternative was VMware. Second, ec2 initially used Paravirtualization exclusively, meaning hardware-assited virtualization functionality wasn't required or used, and performance was extremely good, but compatibility was limited to Xen-aware Linux systems. Fast forward to today and KVM-enabled kernels are performance-comparable to Paravirtualized Xen instances, good Windows drivers exist for KVM virtualized hardware, and maybe most importantly, KVM is part of the kernel of all major Linux distributions.
    • KVM is bundled with your kernel and is plug-and-play.
      The only comparable open-source alternative is Xen, which has slightly more advanced features but is also very less stable.

    • by sjames ( 1099 )

      apt-get install kvm is a pretty nice start.

      The virt-manager isn't bad either even if it does still have a few limitations, so apt-get install virt-manager

      Very nice, straightforward, easily added to any modern server (after the fact if needed). It also works nicely on a good desktop machine.

      • I used virt-manager for quite a while to hold my hand when making and administering guests, but I've always found it a little buggy, and now pretty much work exclusively out of virsh itself. Maybe some day I'll get up the guts to go straight to using kvm itself.

        • by sjames ( 1099 )

          I like Virt-manager for it's at-a-glance view of multiple servers and it's handy for quickly popping a console open.

  • Xen has been ported to ARM64 aswell! In addition to Xen port to ARM32 / ARM Cortex-A15.

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