Some time back, VMware has released one of important KBs on “Hypervisor-Assisted Guest Mitigation for branch target injection”. Please take a look at this KB here. In this KB, there is one important section on “how to confirm a host has both patched microcode and patched VMware hypervisor?” and below is what is posted on KB.
Confirmation of Correct Operation
To confirm a host has both patched microcode and patched VMware hypervisor, use the following steps:
1.Power on a Virtual Machine which is configured to use Virtual Hardware Version 9 or later.
2.Examine the vmware.log file for that VM and look for one of the following entries:
“Capability Found: cpuid.IBRS”
“Capability Found: cpuid.IBPB”
“Capability Found: cpuid.STIBP”
3. Any of the above log entries indicates that both the CPU microcode and hypervisor are properly updated.
I thought it would be really handy if we automate it using PowerCLI. Accordingly, I started looking for any existing cmdlets which can help me to retrieve the VM logs (specially vmware.log) and I could see PowerCLI guru Luc Dekens had written a article on retrieving VM logs long back. I leveraged the same and came up with one quick PowerCLI script to confirm whether a host has both patched microcode and patched VMware hypervisor or not. Here we go.
Update 03/20: As per this KB, new ESXi/vCenter patches are available, hence update (01/13) posted below is no more valid. Once you start applying new patches, please start using either PowerCLI script discussed in this blog post or my latest pyVmomi script for the same.
Script execution steps:
i) It gets all the connected hosts inside the specified cluster. It can be easily modified to consider host from particular datacenter as mentioned above.
ii) It will then iterate through each host in sequence and create a dummyVM.
iii) DRS automation on created dummyVM will be disabled since we need to powerON the VM and if DRS is enabled on the cluster, as part of DRS initial placement workflow, it may place/powerON the VM on some other host inside the cluster.
iv) Now it will powerON the dummyVM
v) Download the vmware.log file at specified location
vi) Scan for the log lines specified in KB (posted above) & record the results.
vii) PowerOff the created VM (to avoid any disk space utilization, you can choose to delete this VM as well)
viii) Step iii) through viii) will repeated for every host inside the cluster.
xi) Finally log the result into one CSV file. CSV file will have HostName & Status (Patched or Un-Patched). Refer CSV sample below.
Script is available on my git-hub repo as well
Sample CSV file result:
1. For the sake of simplicity I have hardcoded some values, please do change as per your environment.
2. If you have any comment/feedback on above script, please do provide.
3. There can be other ways to automate the same. Since I started with this approach, I continued. I haven’t yet thought about other approach (probably we may be able to just use datastore browser APIs to navigate/scan vmware.log file instead of downloading it outside).
4. I would recommend you to use this script as sample and make changes as needed. Let me know what changes you did or probably any other way you found.
5. I have tested this script on vCenter/ESXi 6.5 & it worked as expected for me. I will update this article as I update above script
Note: I would like you to understand “vMotion and EVC Information” section from KB, specially below lines. Let me know if you have any doubts I can share my understanding.
“In order to maintain this compatibility the new features are hidden from guests within the cluster until all hosts in the cluster are properly updated”
I hope this will be helpful.
Vikas Shitole is a Staff engineer 2 at VMware India R&D. He currently focusses on vCenter server in general, vSphere with Tanzu, VCF and partly VMware cloud. He is passionate about VMware customers & automation around VMware technologies. He has been a vExpert since last 9 years (2014-22) in row for his significant community contributions around VMware. He is also part of BU driven vExpert sub-programs i.e. vExpert App modernization, vExpert VMware Cloud on AWS & vExpert PRO as well. He is author of 2 VMware flings & holds multiple technology certifications. He has been speaker at International conferences such as VMworld Europe, VMworld USA & was designated VMworld 2018 blogger as well.
In addition, he is passionate cricketer, bicycle rider & aspiring Ironman 70.3. He also enjoys learning about fitness & nutrition.