From 0047fcade4cb1204cafdf62150081a39356f4dbd Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 1 May 2020 21:32:33 -0700 Subject: [PATCH] KVM: VMX: Move nested EPT out of kvm_x86_ops.get_tdp_level() hook 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 Message-Id: <20200502043234.12481-10-sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx/vmx.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index a7dca7e305b4..7a43fbe05e2d 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -3023,13 +3023,21 @@ void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0) vmx->emulation_required = emulation_required(vcpu); } +static int vmx_get_tdp_level(struct kvm_vcpu *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)); - if (cpu_has_vmx_ept_5levels() && (cpuid_maxphyaddr(vcpu) > 48)) - return 5; - return 4; + + return vmx_get_tdp_level(vcpu); } u64 construct_eptp(struct kvm_vcpu *vcpu, unsigned long root_hpa) @@ -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,