Windows 11 Virtual Machine Panic when installing legacy PCIe drivers for a PCI passthru device.

Products

• VMware vSphere ESXi

Issue/Introduction

• Windows 11 Virtual Machine
  
  
• PCIe Passthru Device configured
  
  
• Legacy PCIe driver
  
  
• vmware.log file:
  
  2026-01-1T01:01:01.111Z In(05) vcpu-1 - Backtrace:
  2026-01-1T01:01:01.111Z Wa(03) mks - Panic in progress... ungrabbing
  2026-01-1T01:01:01.111Z In(05) mks - MKS: Release starting (Panic)
  2026-01-1T01:01:01.111Z In(05) mks - MKS: Release finished (Panic)
  2026-01-1T01:01:01.111Z In(05) vcpu-1 - Backtrace[0] 
  2026-01-1T01:01:01.111Z In(05) vcpu-1 - [msg.log.error.unrecoverable] VMware ESX unrecoverable error: (vcpu-1)
  2026-01-1T01:01:01.111Z In(05)+ vcpu-1 - VERIFY bora/devices/pcipassthru/pciPassthru.c:1071

Environment

Esxi 8.x

Cause

Unsupported PCIe device with an unsupported legacy driver.

Resolution

• Confirm device is listed in the Broadcom Compatibility Guide and ensure Server vendor and device vendor supports the configuration.
  
  
• Confirm that the Guest OS release running in the Virtual Machine is compatible with the ESXi release in the Broadcom Compatibility Guide.
  
  
• Ensure a recommended/certified in-guest device driver provided by the device vendor or guest operating system vendor is installed in the guest operating system. 

Additional Information

Before configuring a device for PCI Passthrough, ensure that platform and device meets the PCI Passthrough requirements, see VMware vSphere VMDirectPath I/O: Requirements for Platforms and Devices.