Linux 5.9 Dropping Xen 32-bit PV Guest Support

[phoronix]

Phoronix: Linux 5.9 Dropping Xen 32-bit PV Guest Support

Back in Linux 5.4 Xen 32-bit PV guest support was deprecated while now for Linux 5.9 it's set to be removed entirely. Last year's deprecation comes with the 32-bit usage dwindling in general but PVH being preferred to PV, Meltdown mitigations not being present, and the code not seeing much activity. Now for Linux 5.9 that support is being gutted...

http://www.phoronix.com/scan.php?page=news_item&px=Linux-5.9-Drops-Xen-32-Bit-PV

[brent]

Dumb question, but isn't Xen pretty much dead anyway? Everyone I know either has moved off to KVM or VMWare ESX or is planning to migrate from Xen to something else.

[CommunityMember]

Dumb question, but isn't Xen pretty much dead anyway? Everyone I know either has moved off to KVM or VMWare ESX or is planning to migrate from Xen to something else.

Last I knew AWS, for their legacy instance types, were still a big user of Xen tech, even while newer instance types use KVM tech.

[olivier]

Dumb question, but isn't Xen pretty much dead anyway? Everyone I know either has moved off to KVM or VMWare ESX or is planning to migrate from Xen to something else.

It's not a dumb question, it's a common misconception Xen as an hypervisor is used in a wide range of applications, but it's often not told because it's not the "final product". It's used from very large Cloud providers (cf my other answer below) to embed use cases (automotive, security etc). It's ported on ARM and widely used there. Xen design is great for security due to its design (there's reasons a LOT of security companies are using it into their product, even BitDefender). Also, it's currently backed by large companies.

The only "visible" product using Xen into traditional server virtualization market was XenServer. But Citrix decided to stop competing with VMware for a lot of reasons, that were mainly not technical but political. Anyway, since 2018, XCP-ng successfully forked XenServer and since then, it's coming back into server virtualization workload. XCP-ng is now even a project hosted the Linux Foundation. And it reached 100k unique downloads in last April!

Also, there's large companies now using XCP-ng at scale (thousand of hosts). I think we can say Xen isn't dead and growing back in the server virtualization space, but also growing where you don't expect it or don't see it usually (embed and security world).

Last I knew AWS, for their legacy instance types, were still a big user of Xen tech, even while newer instance types use KVM tech.

Well, that's not accurate. For AWS, vast majority of instances are running Xen, as you can see on this recent interview of AWS, by Chris Schlaeger, director of kernel and operating systems:

"We have no intention to switch the systems that are running Xen to Nitro. Nitro isn't just a hypervisor and it's not a one-to-one replacement of Xen."

Source

There's also more contribution than ever on Xen project by AWS people, recently (even very cool live Xen upgrade!). They also hired a lot of Xen developers in the last 2 years. So Xen continue to drive most of AWS instances, and they continue to bring resources in it.

[uid313]

What other 32-bit stuff is next up for removal?