KVM: VMX: Move nested EPT out of kvm_x86_ops.get_tdp_level() hook (0047fcad) · Commits · 戴 / test

Separate the "core" TDP level handling from the nested EPT path to make it clear that kvm_x86_ops.get_tdp_level() is used if and only if nested EPT is not in use (kvm_init_shadow_ept_mmu() calculates the level from the passed in vmcs12->eptp). Add a WARN_ON() to enforce that the kvm_x86_ops hook is not called for nested EPT. This sets the stage for snapshotting the non-"nested EPT" TDP page level during kvm_cpuid_update() to avoid the retpoline associated with kvm_x86_ops.get_tdp_level() when resetting the MMU, a relatively frequent operation when running a nested guest. No functional change intended. Signed-off-by:

Sean Christopherson <sean.j.christopherson@intel.com> Message-Id: <20200502043234.12481-10-sean.j.christopherson@intel.com> Signed-off-by:

Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx/vmx.c

+12 −4

Original line number	Diff line number	Diff line
		@@ -3023,15 +3023,23 @@ void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
		vmx->emulation_required = emulation_required(vcpu);
		}

		static int get_ept_level(struct kvm_vcpu *vcpu)
		static int vmx_get_tdp_level(struct kvm_vcpu *vcpu)
		{
		if (is_guest_mode(vcpu) && nested_cpu_has_ept(get_vmcs12(vcpu)))
		return vmx_eptp_page_walk_level(nested_ept_get_eptp(vcpu));
		WARN_ON(is_guest_mode(vcpu) && nested_cpu_has_ept(get_vmcs12(vcpu)));

		if (cpu_has_vmx_ept_5levels() && (cpuid_maxphyaddr(vcpu) > 48))
		return 5;
		return 4;
		}

		static int get_ept_level(struct kvm_vcpu *vcpu)
		{
		if (is_guest_mode(vcpu) && nested_cpu_has_ept(get_vmcs12(vcpu)))
		return vmx_eptp_page_walk_level(nested_ept_get_eptp(vcpu));

		return vmx_get_tdp_level(vcpu);
		}

		u64 construct_eptp(struct kvm_vcpu *vcpu, unsigned long root_hpa)
		{
		u64 eptp = VMX_EPTP_MT_WB;
		@@ -7859,7 +7867,7 @@ static struct kvm_x86_ops vmx_x86_ops __initdata = {

		.set_tss_addr = vmx_set_tss_addr,
		.set_identity_map_addr = vmx_set_identity_map_addr,
		.get_tdp_level = get_ept_level,
		.get_tdp_level = vmx_get_tdp_level,
		.get_mt_mask = vmx_get_mt_mask,

		.get_exit_info = vmx_get_exit_info,

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