Re: [PATCH v6 06/13] KVM: nVMX: optimize prepare_vmcs02{,_full} for Enlightened VMCS case

[Paolo Bonzini]

On 16/10/2018 18:50, Vitaly Kuznetsov wrote:
> +	if (!hv_evmcs || !(hv_evmcs->hv_clean_fields &
> +			   HV_VMX_ENLIGHTENED_CLEAN_FIELD_GUEST_GRP2)) {
> +		vmcs_write16(GUEST_CS_SELECTOR, vmcs12->guest_cs_selector);
> +		vmcs_write32(GUEST_CS_LIMIT, vmcs12->guest_cs_limit);
> +		vmcs_write32(GUEST_CS_AR_BYTES, vmcs12->guest_cs_ar_bytes);
> +		vmcs_writel(GUEST_ES_BASE, vmcs12->guest_es_base);
> +		vmcs_writel(GUEST_CS_BASE, vmcs12->guest_cs_base);
> +	}

For what it's worth, I suspect that these can be moved to
prepare_vmcs02_full.  The initial implementation of shadow VMCS did not
expose "unrestricted guest" to the L1 hypervisor, and emulation does a
lot of accesses to CS (of course).  Not sure how ES base ended up in
there and not DS base, though...

Paolo