Virtualization News Archives

Now queued up for introduction in the Linux 7.4 merge window later in October is the steal governor driver for preferred CPUs and steal-driven vCPU backoff for today's virtualized world.

A convenient addition that surprisingly hasn't been added to the Linux kernel until now is /sys/devices/system/cpu/sev/sev_status as a new sysfs interface for reporting the AMD Secure Encrypted Virtualization (SEV) status.

Here's some very intriguing work taking place by a Google engineer... With the hyperscalers and other cloud providers pushing for zero-downtime, a set of experimental patches for "Orphaned VMs" allow for the virtual machines to continue to run while the host kernel is offline for security updates or rebooting with the Live Update Orchestrator. The experimental patches and request for feedback from other Linux kernel stakeholders was sent out this weekend on Orphaned VMs.

The Kernel-based Virtual Machine "KVM" changes have landed for the Linux 7.3 merge window that is wrapping up later today.

For those using QEMU as part of the open-source virtualization stack, QEMU 11.1 is now available with a number of new feature enhancements and fixes.

Thanks in part to the power of Claude Opus 5 and Claude Fable 5, a new Windows DirectX 11 driver for QEMU has been created to help improve graphics acceleration for Microsoft Windows guests running under QEMU virtual machines.

Made public earlier today is Zapscape as a guest-to-host escape vulnerability affecting the Linux KVM x86 code for the past six years. This 2020 kernel change to KVM x86 can also be used as a local privilege escalation (LPE) exploit too where /dev/kvm is world-writable on some Linux distributions like RHEL.

The Xen Project today released Xen 4.22 as the newest feature release of this open-source hypervisor popular for open-source virtualization in automotive systems and other embedded use-cases as well as the cloud.

A patch series that appears destined for the upcoming Linux 7.3 merge window is what's dubbed the "KVM Chainsaw" as a major code clean-up in dealing with the kvm_mmu "god data structure".

Cloud Hypervisor 53.0 is now available for this open-source, Rust-based VMM focused on cloud workloads and modern security needs. Originally started at Intel, Cloud Hypervisor continues seeing new development these days by Microsoft, Meta, Arm, and other organizations.

The KVM virtualization-related changes were merged a few days ago for the ongoing Linux 7.2 kernel merge window. While there are a number of features/improvements for AMD and Intel virtualization as well as the likes of s390 and RISC-V, there aren't any new features on ARM64. The lack of ARM64 feature work this cycle is being attributed to "so many AI-fueled fixes" swamping the ARM Linux developers.

Interesting feature work for VMware virtualization on Linux now being pursued by Broadcom is to support zero-copy buffer sharing between the VM(s) and host hypervisor, which would equate to an efficiency and performance win.

Among the Kernel-based Virtual Machine (KVM) work being queued ahead of the upcoming Linux 7.2 merge window are preparations for supporting Advanced Performance Extensions within KVM virtual machines.

The QEMU processor emulator that plays an important role in the open-source Linux virtualization stack had a policy that forbid any contributions including or derived from AI-generated content. But there are now second thoughts with a proposed patch that will permit AI/LLM contributions in non-critical areas.

For what originally began as an open-source Intel software project, Cloud Hypervisor continues seeing robust development outside the confines of Intel Corp these days with ongoing improvements driven by Microsoft, Cyberus Tech, Ant, and other organizations for this Rust-based VMM for cloud workloads.

Introduced to the Linux kernel last year was Control-flow Enforcement Technology "CET" virtualization for modern AMD and Intel CPUs. This complements CET that has existed in Linux for quite some time but it's new now to the KVM virtualization world, but some yet to be diagnosed problems are causing some hosts to hang when making use of this virtualization security feature.

At the start of April was the peculiar announcement of IBM collaborating with Arm on "dual architecture" hardware. The initial fruits of that collaboration at least are Linux kernel patches for enabling ARM64 virtualization acceleration on IBM Z servers. As we approach the end of the month, IBM has now posted a second iteration of those patches for enabling AArch64 software to run on IBM s390 via the Kernel-based Virtual Machine (KVM).

The QEMU 11.0 emulator is now available for this important piece of the open-source Linux virtualization stack.

The Kernel-based Virtual Machine changes were recently merged for the Linux 7.1 merge window for further enhancing KVM as this important piece of the open-source virtualization stack.

A small but important patch that looks like it will be merged for the upcoming Linux 7.1 kernel is for enumerating AVX-512 BMM support for KVM virtualized guests. AVX-512 BMM is one of the exciting ISA additions with next-gen AMD Zen 6 processors.

Following this morning's announcement of IBM working with Arm on "dual architecture" hardware, we have some more details on at least what's happening from the software side... It's improving Arm virtualization on IBM Z Systems (s390).

Intel's Advanced Performance Extensions (APX) debuting with Nova Lake and Diamond Rapids is ready with Linux 6.16+ and recent open-source compilers. One piece of the support puzzle still coming together though that will be especially important for Xeon Diamond Rapids is the KVM virtualization support. New patches there were posted this week.

Cloud Hypervisor 51 is now available for this Rust-based VMM focused on secure cloud computing. For what began as an Intel open-source project years ago is continuing to be largely led by Microsoft, Cyberus Tech, Tencent, Ant Group, and others.

All of the KVM virtualization feature changes were recently merged for the in-development Linux 7.0 kernel.

As of this week Oracle's latest VirtualBox development code begins to work with Linux's native KVM back-end. Support for KVM or other native OS hypervisors in conjunction with VirtualBox has long been sought and it's finally becoming a reality.

Libvirt 12.0 released today as this open-source virtualization API for management across different virtualization technologies/hypervisors. With libvirt 12.0, improving Bhyve as the FreeBSD hypervisor was a big focus.

The oVirt 4.5.7 open-source virtualization management platform released this week after not seeing any new releases in two years. While Red Hat had started the oVirt open-source project for which their Red Hat Virtualization platform is based, since they shifted that to maintenance mode to focus on the Red Hat OpenShift platform and stopped contributing to oVirt, it's been up to the open-source community to keep it going.

The QEMU emulator already deprecated 32-bit host CPU support while for the QEMU 11.0 release this year they could eliminate the 32-bit host support for good.

As a wonderful gift to open-source Linux virtualization users this Christmas Eve is the release of the QEMU 10.2 emulator.

Cloud Hypervisor 50.0 is out today for this cloud-minded, security-focused and Rust-based hypervisor. Cloud Hypervsior began as an open-source Intel project while in more recent times has shifted to being largely maintained by Microsoft, Crusoe, Cyberus Tech, Rivos, and others.

The Kernel-based Virtual Machine "KVM" updates for Linux 6.19 include preparations by AMD for handling up to a possible 4,096 virtual CPUs for VMs.

Sean Christopherson of Google sent out the pull requests to the KVM tree of the various x86_64-related areas of virtualization he oversees. With these updates ahead of the Linux 6.19 merge window there is a significant overhaul of Intel's Trust Domain Extensions (TDX) code to address various outstanding problems.

AWS engineers have been working on Linux kernel improvements to KVM's VMX code for enhancing the unmanaged guest memory when dealing with nested virtual machines. The improved code addresses some correctness issues as well as delivering wild performance improvements within a synthetic benchmark.

Xen 4.21 is out today as the newest feature release for this open-source hypervisor backed by AMD, Arm, AWS, and other organizations. Plus with Xen's use within automotive environments, Ford and Honda too.

For what began as an Intel open-source project focused on delivering a modern VMM for cloud workloads and written in Rust is seeing increasingly more exposure on AArch64 and Microsoft Windows platforms. In fact, Intel remains largely inactive now with Cloud Hypervisor after their lead maintainer left the company last year and has now been one year since seeing any significant contributions from Intel to this open-source project.

In recent days there have been two rounds of Kernel-based Virtual Machine "KVM" feature updates to be merged for Linux 6.18 in enhancing the open-source virtualization stack.

The VFIO subsystem updates were merged last week for the ongoing Linux 6.18 merge window.

Control-Flow Enforcement Technology "CET" is coming to the virtualized world with support for running within KVM guest VMs on Linux 6.18+. This CET virtualization support works for both AMD and Intel processors.

A patch making it to a TIP Git branch this week adds Linux kernel support for detecting the FreeBSD Bhyve hypervisor, which will become important with today's growing server CPU counts.

Cloud Hypervisor 48.0 is now available for this Intel-started, open-source and Rust-based VMM focused on modern cloud workloads. Cloud Hypervisor continues to tailor to Windows and Linux guests while emphasizing security and cloud-native workloads.

A new set of Linux kernel patches posted today work to improve the nested VMX performance for benefiting Intel processors making use of KVM virtualization.

QEMU 10.1 was released overnight as the latest iteration of this open-source machine emulator that plays an important role in the Linux virtualization stack.

Some old and unmaintained drivers for Linux's Virtual Function I/O (VFIO) support are being marked as deprecated for eventual removal, including the generic VFIO platform driver.

The KVM feature changes were merged a few days ago with all of their enhancements for the in-development Linux 6.17 kernel. Some nice improvements made it this cycle for enhancing the open-source Linux virtualization stack.

There are a few AMD Secure Encrypted Virtualization improvements on the way for the Linux 6.17 kernel worth noting.

For those making use of Open Virtual Machine Firmware (OVMF) such as for UEFI booting of VMs with KVM+QEMU, the upcoming Linux 6.17 kernel is set to offer a convenient new driver to help in debugging the system boot when needed.

Cloud Hypervisor is the open-source, Rust-based VMM started originally by Intel engineers but under the stewardship of the Linux Foundation has evolved into a nice multi-vendor initiative with the likes of Microsoft, Cyberus, Arm, and others all contributing. Even with Intel's cutbacks due to their ongoing corporate restructuring, the Cloud Hypervisor project is thriving as a multi-vendor open-source project for a security-focused hypervisor.

In addition to releasing Oracle Linux 10 today, Oracle also released the second beta of the upcoming VirtualBox 7.2 cross-platform virtualization software.

Merged minutes ago ahead of the Linux 6.16-rc3 release due out shortly was this week's batch of Kernel-based Virtual Machine (KVM) updates. Beyond the usual KVM fixes merged for the week, a bit of feature code was pulled in by Linus Torvalds for this post-merge-window phase.

Following the Intel TDX host support for KVM being merged for the Linux 6.16 merge window, another batch of Kernel-based Virtual Machine (KVM) changes were merged for the ongoing Linux 6.16 merge window.