Re: [PATCH 03/26] KVM: arm64: Factor out stage 2 page table data from struct kvm

quoted

quoted

+	/* 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?

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