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The GPU multitenancy mess

We’re seeing an interesting infrastructure tug of war today where GPU clouds are being pulled in two directions. For the economics of AI to work, the enterprise market needs to carve expensive hardware into smaller, shareable units and hand it to customers on demand, similar to how CPUs are doled in public cloud infrastructure. But the more the providers push GPUs to behave like elastic cloud infrastructure, the more they run into the reality that this GPU hardware was never built for safe multitenant use, fast fault recovery, or clean isolation between workloads. That tension is becoming one of the defining operational problems of the AI infrastructure market.

When a gamer launches Steam or the Epic Games Store on their laptop, they don’t have to worry about which GPU is being scheduled, how memory is going to be divided, or really any of the security boundaries or hardware assignment issues on their PC. For consumer PCs, these issues are not just hidden from view, they are irrelevant.

But for today’s IT teams managing GPU-driven AI workloads across distributed systems, those types of allocations and partitions need to be managed manually and carefully. This includes deciding which GPU to assign to each workload, how to divide memory, how to isolate tasks, and how to maximize utilization of this very expensive hardware. That’s why you heard so much about “Day 2” AI infrastructure themes around Nvidia’s GTC event this year.

The legacy hardware bottleneck

GPUs were originally developed to speed up graphic rendering and to perform local compute via shaders in service of graphical rendering. Their design assumes a trusted computing environment in which a single application controls the device. When a user runs an application on a GPU, it accelerates that particular workload.

But while GPUs are optimized for throughput, and therefore have thousands of simple cores designed to execute the same instruction over large datasets, this design paradigm creates several major technical limitations regarding context switching and memory isolation. GPUs were designed to produce pixels, not to run sensitive AI applications from multiple tenants using the same hardware.

As a result, GPU infrastructure today behaves less like elastic cloud infrastructure and more like carefully managed hardware appliances.

The partitioning paradox

Today’s AI infrastructure requires GPUs to behave like shared, elastic cloud resources. As inference workloads begin to outstrip large-scale training runs, the ability to slice and share expensive hardware among multiple tenants in real time while maintaining acceptable fault tolerance is no longer optional.

Hardware vendors have introduced new approaches to dividing GPUs into multiple isolated compute slices. Other frameworks approach partitioning through schedulers and container runtimes. But resource partitioning is just one slice of the overall GPU operations pie.

There is currently no widely adopted, cross-vendor operating model for achieving this safely at scale. Most providers are faced with either dedicating a single customer to a physical machine (thus wasting available capacity), or accepting the multi-tenancy security risks currently without a known solution. The current engineering challenge has moved from beneath the model layer and into the infrastructure layer. Success now relies on the ability to quickly launch new workloads and to rapidly contain hardware faults so that a single GPU failure does not bring down all workloads running on the server.

Untrusted code and tenants

The vast majority of current GPU programming models rely on the idea that the driver has complete control over memory protection and that no user will act maliciously. Unfortunately, that assumption completely falls apart in a cloud environment where one VM or container can leave behind data remnants in memory that another VM or container may access. Especially considering that how GPUs execute code is often completely opaque.

A single faulty workload or a single faulty driver failure in a shared GPU environment can also take down every workload (job) that was being run on the same server, increasing the amount of damage caused by an operational failure.

Currently, there are immature options for runtime inspection or behavioral auditing, limiting both visibility and control for security teams. GPU drivers provide a large attack surface and generally limited telemetry from the hardware. In these shared environments, embeddings, weights, prompts, and tokens are now all sensitive data points, creating significant blind spots for those attempting to protect intellectual property.

The high cost of cold starts

The real constraint in many GPU clouds is not model performance but operational efficiency. Right now GPU operations looks like 30 minute tenant spin-up times, 70% idle rates, and engineers continuously debugging infrastructure stacks. Today’s GPU clouds are stalled not due to inferior models, but because the infrastructure layer underpinning these clouds was never designed to support such a high degree of scale.

A 30 minute cold start is a fundamental limitation on the modern AI business model. Those GPU clouds that can spin up workloads in seconds will ultimately win against those that do not. Multitenancy is the only viable means of producing sufficient unit economics to make this very expensive hardware viable for the long term.

Bridging the orchestration gap

Platform teams are beginning to recognize that GPUs require a specialized operating layer between the hardware and workloads. Operators need a unified operating model that supports multiple hardware vendors and GPU models. Cloud providers need a method to safely slice and share servers among tenants, and to prevent cascading failures, while rapidly launching new workloads.

Enterprises are increasingly seeking to run sensitive AI applications with stronger isolation guarantees, and thus are turning to newer categories of software designed specifically to manage the “dirty work” of hardware orchestration.

The race to make GPUs more operational

Prior to Kubernetes standardizing container orchestration, the industry was constantly debating the efficiency of container scheduling and bin packing across clusters. Those operational concerns were eventually automated and incorporated into infrastructure layers that made the complexities invisible to the end user. 

A similar evolution is occurring around GPUs today. While platform teams continue to argue over placement strategies and memory tuning, these decisions will likely be automated within five to 10 years. As AI infrastructure evolves, the most valuable layer may not be the GPUs themselves but the operating layers that make them secure, elastic, and efficiently sharable. So the winners in the AI race won’t necessarily be just those with the most silicon, but those who have the best operating models for making that silicon secure and elastic.

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New Tech Forum provides a venue for technology leaders—including vendors and other outside contributors—to explore and discuss emerging enterprise technology in unprecedented depth and breadth. The selection is subjective, based on our pick of the technologies we believe to be important and of greatest interest to InfoWorld readers. InfoWorld does not accept marketing collateral for publication and reserves the right to edit all contributed content. Send all inquiries to doug_dineley@foundryco.com.

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Broadcom beefs up Spring security to protect against AI-enabled attacks

Broadcom today announced multiple security investments in its Spring and Java ecosystems that aim to help protect users from AI-enabled threats.

The company said that, first, it is releasing what it called the largest set of Spring security updates to open source in the product’s history, and, for customers, it is extending its clean-room build architecture to build the Java dependencies for the entire Spring ecosystem.

“Spring is one of the most widely adopted application development frameworks in the world, and as its steward, we have a deep responsibility for its security,” said Purnima Padmanabhan, vice president and general manager of Broadcom’s Tanzu Division. “Because we maintain Spring and are the sole committers, we can better secure it at the source for everyone who depends on it. This investment is about two things we will never separate: the health of the Spring community and the security of our customers who trust Spring to run their business.”

The company also announced that, as the number of security advisories reported by the community has exploded, its engineering team has “significantly scaled” its use of AI tools to help it identify vulnerabilities, assess remediation paths, and validate fixes across the dependency ecosystem. Although Broadcom declined to specify the AI models it’s using in its bug hunting, it is a member of Anthropic’s Project Glasswing, so Claude Mythos is likely part of the effort.

For paying customers only

One perk available only to Tanzu Spring enterprise customers is zero-day access to validated CVE patch-only releases through the Spring Enterprise Repository, before they are released to open source. These patches isolate the security fix from any other changes to let customers remediate more quickly.

“By utilizing Tanzu Spring’s private artifact repositories, customers can be confident that the artifacts are the official, validated patches from Broadcom, the steward of Spring,” Broadcom said in its announcement, adding that it will continue to issue CVEs for all versions of every Spring project under open source support, as well as older versions under Tanzu Spring enterprise support.

Broadcom’s Tanzu Spring enterprise support includes:

  • Certified source for secure spring libraries 
  • Commercial-first release of patches for both current and older, enterprise supported versions
  • Access to dependent Java binaries
  • Automated, deterministic upgrades with Spring Application Advisor
  • Exclusive Tanzu Spring components for governance and security
  • 24×7 support, hands-on expertise and access to the Spring team.

In addition, Broadcom said, it has now added:

  • Secured, SLSA Level 3–validated software supply chain for Java dependencies.
  • Coverage that spans the full transitive dependency graph managed by the Spring Boot bill of materials.
  • Thousands of secured dependencies, built and tested across every supported Spring version. Spring Boot 4.0 alone manages 1,768 of them; across the full supported portfolio, that totals more than 100,000 validated dependency builds.

“This capability gives customers validated dependencies across both current and end-of-life Spring versions, helping customers reduce software supply chain risk while continuing to benefit from the productivity and consistency of Spring Boot’s dependency management model,” the announcement noted.

Security fixes for sale

Seva Ioussoufovitch, senior research analyst at Info-Tech Research Group, sees these moves as mostly positive.

“It’s encouraging to see Broadcom take proactive steps towards dealing with the increase in AI-detected vulnerabilities that many organizations have had to contend with in recent months,” he said. “Announcements like Mythos have made it clear that the industry needs to re-think traditional approaches to security patching.”

Ioussoufovitch isn’t surprised at the size of the update release either, noting that it’s consistent with the result of AI scanning and remediation that has been occurring, and will likely continue.

“More meaningful is the provision of validated and secured dependencies,” he said. “This is a critical move in the right direction, especially with the endlessly growing list of supply chain vulnerabilities the industry has been managing in recent months.”

Ioussoufovitch is less happy with the restriction of zero-day patches to paying customers.

“Putting security fixes behind a paywall isn’t new, but when there are no drop-in alternatives for an ecosystem as critical as Spring, it just looks like a power move to force more of the open-source community onto the monetization track,” he noted. “Another approach might’ve been to release the CVE fixes to everyone while charging for enterprise-grade packaging, validation, and support, but, given Broadcom’s track record of aggressive monetization in recent years, what they’ve chosen here doesn’t necessarily come as a shock.”

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Windows 11 Smart App Control explained

In the ever-evolving cybersecurity landscape, Microsoft has introduced various new features in Windows 11 designed to protect users from modern workplace threats. Among such features, Smart App Control (SAC) changes how Windows devices handle, and occasionally block, unwanted or potentially malicious applications.

But what exactly is Smart App Control? How does it work, who benefits most, and are there any caveats? In this story we’ll share some history and explain why SAC has been something of a stealth feature in Windows 11.

What is Smart App Control?

Smart App Control is a security feature in Windows 11 designed to block untrusted or potentially dangerous applications from running on a PC. Built directly into the operating system (through Windows Security), SAC leverages code signing, Microsoft’s intelligence cloud, and artificial intelligence to make real-time decisions about whether an app or application should be allowed to run. Its goal is to minimize the risk that malware, ransomware, and unwanted software could run on users’ systems — with minimal user intervention.

At its heart, Smart App Control is a kind of gatekeeper. When you attempt to run an app, SAC evaluates its trustworthiness. That evaluation is based on numerous criteria: Is the app digitally signed? Is it widely used and recognized as safe by Microsoft’s threat intelligence network? Has it been flagged previously for questionable behavior?

If an app fails one or more such checks and is found suspicious or untrustworthy, SAC blocks its execution, silently preventing a potential security event before it starts.

How does Smart App Control work?

SAC operates using a combination of cloud-based intelligence, local analysis, and digital signatures. Here’s a step-by-step breakdown of how it functions:

  • App verification: When a user attempts to launch an application, SAC inspects the file. It first checks if the app is digitally signed by a trusted publisher, an important indicator of legitimacy.
  • Cloud intelligence search: SAC then consults Microsoft’s extensive security databases in the cloud. These aggregate threat data from millions of Windows devices worldwide. If the app has been flagged already or is recognized as part of any malware campaign, it is blocked.
  • AI-based analysis: For less clear-cut instances, SAC uses AI to evaluate an app’s behavior. That is, it looks for telltale signs of malware or unwanted code. Such a dynamic analysis helps catch emerging threats not yet known to the cloud.

When an app is blocked, the user gets a clear, informative notification. Usually, there’s no way to override SAC’s decision, which puts security ahead of convenience. It also ensures that users will quickly report false positives.

Smart App Control is designed to be simple and automatic. Unlike conventional antivirus or endpoint security, it requires no updates to definitions, nor manual scans. SAC works behind the scenes to block threats in real time. Because it uses both local and cloud-based intelligence, it’s always current.

On the downside, some legitimate apps, especially older or custom business software, may not be digitally signed, resulting in false positives. If SAC decides an app is unsafe, the only way to run the app is to turn SAC off.

Working with Smart App Control

Notably, Smart App Control is enabled by default — but only on “clean installs” of Windows 11 version 22H2 or later. Systems upgraded from older versions of Windows 11 will always show SAC in the “Off” state.

Microsoft made this decision to avoid potential compatibility issues with legacy or line-of-business applications. That means users can’t benefit from SAC unless they have a newer PC or somebody reinstalls Windows 11 from scratch on an older one. (See my Windows clean install tutorial for complete instructions.)

SAC prerequisites

To get granular: SAC requires that the following be present as Windows 11 comes up for the first time:

  • Secure Boot, a security feature that allows only trusted, digitally signed software to run as Windows boots up
  • A working chain of trust, including current CA-2023 boot certificates in Unified Extensible Firmware Interface (UEFI) and a CA-2023 compliant bootloader

Newer PCs — namely, those built in 2018 or later, with Windows 10 or 11 installed prior to delivery — routinely include UEFI-only boot and support Secure Boot from the get-go. Indeed, Secure Boot was introduced with Windows 8, and the original certificates came along in 2011 (Production PCA 2011, UEFI CA 2011, and KEK CA 2011). They’ve been shipped in firmware ever since.

As long as such machines get updated through Windows Update (or some managed equivalent, such as Microsoft Intune, Windows Autopilot, or Microsoft Configuration Manager), the new certificates and a proper chain of trust should be established on those PCs. (See FAQ: What you need to know about expiring Windows Secure Boot certificates for more information.) All this said, only Windows 11 imposes a working Secure Boot environment as a hard and fast system requirement as of 2021.

In short, Secure Boot and the chain of trust provide the essential foundation for SAC to start with a clean bill of health, security wise, and keep things that way. To learn more about Secure Boot and its various certificates and trappings, consult the Secure Boot and Windows Secure Boot Key Creation and Management Guidance pages on Microsoft Learn.

Modes of operation

SAC has three distinct modes:

  • On: SAC actively monitors and blocks untrusted apps.
  • Evaluation: SAC quietly observes your usage patterns and system needs before fully activating.
  • Off: SAC is disabled and will not intervene.

SAC will normally start in Evaluation mode for up to a month, then turn itself On or Off depending on observed system behavior. Once turned on, SAC cannot be set back into Evaluation mode. Organizations or users who run custom software or specialized workflows should leave SAC in Evaluation mode to ensure that business functions keep working.

To check SAC’s status:

  1. Open the Windows Security app.
  2. Navigate to App & browser control.
  3. Look for the “Smart App Control” section. You’ll see the current status: On, Off, or Evaluation mode, as shown in Figure 1.
windows 11 smart app control screen in windows security

Figure 1: On this PC, the evaluation period is over and Smart App Control is enabled.

Ed Tittel / Foundry

Until recently, SAC could not be toggled off and on again — once it was turned off, you had to reinstall or reset Windows 11 to re-enable it. But with the April 2026 Patch Tuesday release of Windows 11 (KB5083769), admins and elevated users can turn SAC on or off as they see fit, as long as the initial setup conditions described above are met.

This toggling capability is a step forward for usability and safety, because it lets users with administrative privileges temporarily disable SAC in order to install, update, or uninstall certain unsigned apps, such as those that rely on Windows Installer Transform (MST) files, and then turn SAC back on immediately.

Note that this feature is being gradually rolled out, so you may not have access to it yet.

Smart App Control compared to other Windows 11 protections

Microsoft has long offered security features like Windows Defender, Controlled Folder Access, and Application Control. SAC differs in its general, automated approach. Rather than relying on static definitions, group policies, or user input, SAC leverages real-time intelligence and AI.

In many ways, SAC takes the best bits of Application Control (previously available through Device Guard and Windows Defender Application Control) and makes them accessible to a wider audience. It also involves little or no manual setup and few, if any, policy issues. Then again, as covered earlier in the story, SAC also functions as a black box: one either lives with its judgments, or does without it.

Real-world impact and industry reception

Feedback from the IT community has been mostly positive. Security researchers note SAC’s ability to block emerging threats before traditional antivirus solutions can respond. But SAC is hardly bullet-proof: a number of studies cite focused exploits or workarounds to bypass or trick SAC. For instance, Elastic Security Labs documented multiple techniques to break SAC in 2021, with follow-ons from Hacker News and TechRadar.

As always, a proactive approach to cybersecurity that includes teaching users to avoid trouble remains a key ingredient in establishing and maintaining a strong security posture.

For end users, SAC’s presence may go largely unnoticed — until, that is, it intercepts a malicious download or prevents installation of a suspicious or malicious program. Or, as the case may sometimes be, when users try to run old, unsigned software that SAC won’t allow.

Tips for IT administrators

For IT professionals considering deploying devices with SAC, certain best practices are worth implementing:

  • Test SAC in Evaluation mode before rolling out widely, especially if your organization relies on custom or legacy software, or if anything important is unsigned.
  • Educate users about SAC’s presence and purpose so they understand why certain apps may be blocked. Set up a procedure to request support and/or fixes, particularly if important software gets blocked. Possible workarounds include restricted VMs with SAC turned off to run unsigned applications.
  • Maintain an up-to-date inventory of critical applications and ensure as many as possible are digitally signed by trusted publishers.
  • Monitor Microsoft resources Learn, Support, and Answers forums for SAC updates, compatibility lists, and troubleshooting tips.

The future of Smart App Control

As threats continue to evolve, Microsoft should continue to expand SAC’s capabilities. Undoubtedly it will use more advanced AI models and deeper integration with Windows Defender and Microsoft 365 security. Future updates may introduce more granular controls for enterprise environments, including managed exceptions and better reporting tools.

For now, SAC represents a useful additional tool for Windows security. It’s intended to shift the balance in favor of the good guys in the ongoing war against malware. So far, it’s been a modest step forward. But it’s not unthinkable that SAC could offer more and better protection in upcoming Windows releases.

[Also see: FAQ: What you need to know about expiring Windows Secure Boot certificates]

This article was originally published in September 2025 and updated in June 2026.

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