KVM: TDX: Add methods to ignore accesses to TSC

TDX protects TDX guest TSC state from VMM.  Implement access methods to
ignore guest TSC.

Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com>
Message-ID: <20250227012021.1778144-16-binbin.wu@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
index 2e5798d..98e5904 100644 (file)
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -786,6 +786,42 @@ static int vt_set_identity_map_addr(struct kvm *kvm, u64 ident_addr)
        return vmx_set_identity_map_addr(kvm, ident_addr);
 }
 
+static u64 vt_get_l2_tsc_offset(struct kvm_vcpu *vcpu)
+{
+       /* TDX doesn't support L2 guest at the moment. */
+       if (is_td_vcpu(vcpu))
+               return 0;
+
+       return vmx_get_l2_tsc_offset(vcpu);
+}
+
+static u64 vt_get_l2_tsc_multiplier(struct kvm_vcpu *vcpu)
+{
+       /* TDX doesn't support L2 guest at the moment. */
+       if (is_td_vcpu(vcpu))
+               return 0;
+
+       return vmx_get_l2_tsc_multiplier(vcpu);
+}
+
+static void vt_write_tsc_offset(struct kvm_vcpu *vcpu)
+{
+       /* In TDX, tsc offset can't be changed. */
+       if (is_td_vcpu(vcpu))
+               return;
+
+       vmx_write_tsc_offset(vcpu);
+}
+
+static void vt_write_tsc_multiplier(struct kvm_vcpu *vcpu)
+{
+       /* In TDX, tsc multiplier can't be changed. */
+       if (is_td_vcpu(vcpu))
+               return;
+
+       vmx_write_tsc_multiplier(vcpu);
+}
+
 #ifdef CONFIG_X86_64
 static int vt_set_hv_timer(struct kvm_vcpu *vcpu, u64 guest_deadline_tsc,
                              bool *expired)
@@ -944,10 +980,10 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
 
        .has_wbinvd_exit = cpu_has_vmx_wbinvd_exit,
 
-       .get_l2_tsc_offset = vmx_get_l2_tsc_offset,
-       .get_l2_tsc_multiplier = vmx_get_l2_tsc_multiplier,
-       .write_tsc_offset = vmx_write_tsc_offset,
-       .write_tsc_multiplier = vmx_write_tsc_multiplier,
+       .get_l2_tsc_offset = vt_get_l2_tsc_offset,
+       .get_l2_tsc_multiplier = vt_get_l2_tsc_multiplier,
+       .write_tsc_offset = vt_write_tsc_offset,
+       .write_tsc_multiplier = vt_write_tsc_multiplier,
 
        .load_mmu_pgd = vt_load_mmu_pgd,