On Thu, Feb 19, 2026 at 10:33:44AM +0000, Anirudh Rayabharam wrote: [...] > > > > > > Instead of enabling all features by default, we could query which > > > features are supported by the hypervisor on this host and enable only > > > those. > > > > > > To query supported features get the HvPartitionPropertyProcessorFeatures > > > property via HvCallGetPartitionProperty (with HV_PARTITION_ID_SELF). > > > > > > I think this would be more robust. This is what Cloud Hypervisor (well, > > > technically, the mshv crate) does. > > > > > > > While I think querying the hypervisor is the correct action, are we > > sure this gives all the supported features on the host? > > Yes, I confirmed this with the hypervisor team when implementing it in > the mshv crate. > > > > > Is there a case that the Linux root partition has a reduced set of > > properties? > > It is my understanding that the processor features we expose to a guest > must always be a subset of the processor features of the root/parent > partition. So, if some proc feature is not available for root, we cannot > make it available for any guest partitions either.
One thing comes to mind is the confidential VM support. In our CVM implementation, the guest can see a different set of features than the root partition, mostly around SEV-SNP support. I cannot say 100% for sure that if this matters. Wei > > Thanks, > Anirudh. > > > > > Wei > >
