> > > + /* VTCR_EL2 value for this VM */ > > > + u64 vtcr; > > > > VTCR seems quite strongly tied to the MMU config. Is it not controlled > > independently for the nested MMUs and so remains in this struct? > > This particular instance of VTCR_EL2 is the host's version. Which > means it describes the virtual HW for the EL1 guest. It constraints, > among other things, the number of IPA bits for the guest, for example, > and is configured by the VMM. > > Once you start nesting, each vcpu has its own VTCR_EL2 which is still > constrained by the main one (no nested guest can have a T0SZ bigger > than the value imposed by userspace for this guest as a whole). > > Does it make sense? It does up to my ignorance of the spec in this regard. Simliar to James's question, should `vtcr` live inside the mmu struct with the top level `kvm::mmu` field containing the host's version and the nested mmus containing the nested version of vtcr to be applied to the vCPU? I didn't noticed there being a vtcr for the nested version in the ~90-patch series so maybe that just isn't something that needs thinking about?
