[GitHub] [cloudstack] ustcweizhou opened a new pull request #3335: kvm: disable cpu features if feature starts with '-'

[GitBox <gi...@apache.org>]

ustcweizhou opened a new pull request #3335: kvm: disable cpu features if feature starts with '-'
URL: https://github.com/apache/cloudstack/pull/3335
 
 
   When I use SandyBridge as custom cpu in my testing, vm failed to start due to following error:
   ```
   org.libvirt.LibvirtException: unsupported configuration: guest and host CPU are not compatible: Host CPU does not provide required features: avx, xsave, aes, tsc-deadline, x2apic, pclmuldq
   ```
   
   With this patch, it works with the following setting in agent.properties:
   ```
     guest.cpu.mode=custom
     guest.cpu.model=SandyBridge
     guest.cpu.features=-avx -xsave -aes -tsc-deadline -x2apic -pclmuldq
   ```
   
   vm cpu is defined as below:
   ```
     <cpu mode='custom' match='exact'>
       <model fallback='allow'>SandyBridge</model>
       <feature policy='disable' name='avx'/>
       <feature policy='disable' name='xsave'/>
       <feature policy='disable' name='aes'/>
       <feature policy='disable' name='tsc-deadline'/>
       <feature policy='disable' name='x2apic'/>
       <feature policy='disable' name='pclmuldq'/>
     </cpu>
   ```
   
   ## Description
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   <!-- For new features, provide link to FS, dev ML discussion etc. -->
   <!-- In case of bug fix, the expected and actual behaviours, steps to reproduce. -->
   
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   ## Types of changes
   <!--- What types of changes does your code introduce? Put an `x` in all the boxes that apply: -->
   - [ ] Breaking change (fix or feature that would cause existing functionality to change)
   - [ ] New feature (non-breaking change which adds functionality)
   - [ ] Bug fix (non-breaking change which fixes an issue)
   - [X] Enhancement (improves an existing feature and functionality)
   - [ ] Cleanup (Code refactoring and cleanup, that may add test cases)
   
   ## Screenshots (if appropriate):
   
   ## How Has This Been Tested?
   <!-- Please describe in detail how you tested your changes. -->
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   1. add agent.properties to server using KVM,  and restart cloudstack-agent
   
   guest.cpu.mode=custom
   guest.cpu.model=<cpu model>
   guest.cpu.features=<cpu features, seperated by space>
   
   2. create a vm on the server
   
   cpu feature starts with "-" will be disabled, others will be enabled.
   ```
     <cpu mode='custom' match='exact'>
       <model fallback='allow'><cpu mode></model>
       <feature policy='disable' name='<cpu feature starts with "-">'/>
       <feature policy='require' name='<other cpu feature>'/>
     </cpu>
   ```
   <!-- Please read the [CONTRIBUTING](https://github.com/apache/cloudstack/blob/master/CONTRIBUTING.md) document -->
   

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