From 0047fcade4cb1204cafdf62150081a39356f4dbd Mon Sep 17 00:00:00 2001
From: Sean Christopherson <sean.j.christopherson@intel.com>
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 <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 | 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,