On an ESXi host, one or more virtual machines that use SR-IOV virtual functions (VFs) for networking are powered off.
Problem
On an ESXi host, one or more virtual machines that use SR-IOV virtual functions (VFs) for networking fail to power on if the total number of assigned virtual functions is close to the maximum number of VFs specified in the vSphere Configuration Maximums guide.
The virtual machine log file vmware.log contains the following message about the VF:
PCIPassthruChangeIntrSettings: vf_name failed to register interrupt (error code 195887110)
The VMkernel log file vmkernel.log contains the following messages about the VF assigned to the virtual machine:
VMKPCIPassthru: 2565: BDF = vf_name intrType = 4 numVectors: 3 WARNING: IntrVector: 233: Out of interrupt vectors
Cause
The number of allocatable interrupt vectors scales up with the number of physical CPUs on an ESXi host. An ESXi host that has 32 CPUs can provide a total of 4096 interrupt vectors. When the host boots, devices on the host such as storage controllers, physical network adapters, and USB controllers consume a subset of the 4096 vectors. If these devices require more than 1024 vectors, the maximum number of potentially supported VFs is reduced.
When a virtual machine powers on and the guest operating system VF driver starts, interrupt vectors are consumed. If the required number of interrupt vectors is not available, the guest operating system shuts down unexpectedly without any error messages.
No rule presently exists to determine the number of interrupt vectors consumed or available on a host. This number depends on the hardware configuration of the host.
Solution
- ♦ To be able to power on the virtual machines, reduce the total number of VFs assigned to virtual machines on the host.
For example, change the SR-IOV network adapter of a virtual machine to an adapter that is connected to a vSphere Standard Switch or vSphere Distributed Switch.
