CVE-2022-4994
Received Received - Intake

KVM Fast PIO Handling in Linux Kernel

Publication date: 2026-07-30

Last updated on: 2026-07-30

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: KVM: x86: wean fast IN from emulator_pio_in Use __emulator_pio_in() directly for fast PIO instead of bouncing through emulator_pio_in() now that __emulator_pio_in() fills "val" when handling in-kernel PIO. vcpu->arch.pio.count is guaranteed to be '0', so this a pure nop. emulator_pio_in_emulated is now the last caller of emulator_pio_in. No functional change intended.

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Meta Information

Published
2026-07-30
Last Modified
2026-07-30
Generated
2026-08-19
AI Q&A
2026-07-30
EPSS Evaluated
2026-08-18
NVD
CVE-2022-4994
EUVD
EUVD-2022-56012

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability is a minor optimization issue in the Linux kernel's KVM (Kernel-based Virtual Machine) x86 component. It involves replacing a function call to emulator_pio_in() with a direct call to __emulator_pio_in() for handling fast PIO (Programmed Input/Output) operations. The change is described as a 'pure nop' meaning no functional difference is intended.

Detection Guidance

This vulnerability is a Linux kernel issue related to KVM x86 emulation. Detection requires checking kernel version and KVM module behavior. No direct commands are provided in the context to detect this specific issue.

Impact Analysis

This vulnerability has no direct impact on users or systems. It is an internal code optimization in the Linux kernel with no functional changes intended. No security risks or performance issues are associated with this issue.

Compliance Impact

This vulnerability does not affect compliance with standards like GDPR or HIPAA. It is a minor internal code change with no functional impact, security implications, or data exposure risks.

Mitigation Strategies

No immediate mitigation steps are required as this is a non-functional change in the Linux kernel with no security impact. Update to a patched kernel version if available.

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