[PATCH v14 108/113] KVM: TDX: Add methods to ignore virtual apic related operation

[isaku . yamahata]

From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>

TDX protects TDX guest APIC state from VMM.  Implement access methods of
TDX guest vAPIC state to ignore them or return zero.

Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
---
 arch/x86/kvm/vmx/main.c    | 61 ++++++++++++++++++++++++++++++++++----
 arch/x86/kvm/vmx/tdx.c     |  6 ++++
 arch/x86/kvm/vmx/x86_ops.h |  3 ++
 3 files changed, 64 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
index 90a6eb851854..de8d8c70605b 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -363,6 +363,14 @@ static bool vt_apic_init_signal_blocked(struct kvm_vcpu *vcpu)
 	return vmx_apic_init_signal_blocked(vcpu);
 }
 
+static void vt_set_virtual_apic_mode(struct kvm_vcpu *vcpu)
+{
+	if (is_td_vcpu(vcpu))
+		return tdx_set_virtual_apic_mode(vcpu);
+
+	return vmx_set_virtual_apic_mode(vcpu);
+}
+
 static void vt_apicv_post_state_restore(struct kvm_vcpu *vcpu)
 {
 	struct pi_desc *pi = vcpu_to_pi_desc(vcpu);
@@ -371,6 +379,31 @@ static void vt_apicv_post_state_restore(struct kvm_vcpu *vcpu)
 	memset(pi->pir, 0, sizeof(pi->pir));
 }
 
+static void vt_hwapic_irr_update(struct kvm_vcpu *vcpu, int max_irr)
+{
+	if (is_td_vcpu(vcpu))
+		return;
+
+	return vmx_hwapic_irr_update(vcpu, max_irr);
+}
+
+static void vt_hwapic_isr_update(int max_isr)
+{
+	if (is_td_vcpu(kvm_get_running_vcpu()))
+		return;
+
+	return vmx_hwapic_isr_update(max_isr);
+}
+
+static bool vt_guest_apic_has_interrupt(struct kvm_vcpu *vcpu)
+{
+	/* TDX doesn't support L2 at the moment. */
+	if (WARN_ON_ONCE(is_td_vcpu(vcpu)))
+		return false;
+
+	return vmx_guest_apic_has_interrupt(vcpu);
+}
+
 static int vt_sync_pir_to_irr(struct kvm_vcpu *vcpu)
 {
 	if (is_td_vcpu(vcpu))
@@ -808,6 +841,22 @@ static void vt_update_cr8_intercept(struct kvm_vcpu *vcpu, int tpr, int irr)
 	vmx_update_cr8_intercept(vcpu, tpr, irr);
 }
 
+static void vt_set_apic_access_page_addr(struct kvm_vcpu *vcpu)
+{
+	if (is_td_vcpu(vcpu))
+		return;
+
+	vmx_set_apic_access_page_addr(vcpu);
+}
+
+static void vt_refresh_apicv_exec_ctrl(struct kvm_vcpu *vcpu)
+{
+	if (WARN_ON_ONCE(is_td_vcpu(vcpu)))
+		return;
+
+	vmx_refresh_apicv_exec_ctrl(vcpu);
+}
+
 static void vt_load_eoi_exitmap(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap)
 {
 	if (is_td_vcpu(vcpu))
@@ -1018,15 +1067,15 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
 	.enable_nmi_window = vt_enable_nmi_window,
 	.enable_irq_window = vt_enable_irq_window,
 	.update_cr8_intercept = vt_update_cr8_intercept,
-	.set_virtual_apic_mode = vmx_set_virtual_apic_mode,
-	.set_apic_access_page_addr = vmx_set_apic_access_page_addr,
-	.refresh_apicv_exec_ctrl = vmx_refresh_apicv_exec_ctrl,
+	.set_virtual_apic_mode = vt_set_virtual_apic_mode,
+	.set_apic_access_page_addr = vt_set_apic_access_page_addr,
+	.refresh_apicv_exec_ctrl = vt_refresh_apicv_exec_ctrl,
 	.load_eoi_exitmap = vt_load_eoi_exitmap,
 	.apicv_post_state_restore = vt_apicv_post_state_restore,
 	.required_apicv_inhibits = VMX_REQUIRED_APICV_INHIBITS,
-	.hwapic_irr_update = vmx_hwapic_irr_update,
-	.hwapic_isr_update = vmx_hwapic_isr_update,
-	.guest_apic_has_interrupt = vmx_guest_apic_has_interrupt,
+	.hwapic_irr_update = vt_hwapic_irr_update,
+	.hwapic_isr_update = vt_hwapic_isr_update,
+	.guest_apic_has_interrupt = vt_guest_apic_has_interrupt,
 	.sync_pir_to_irr = vt_sync_pir_to_irr,
 	.deliver_interrupt = vt_deliver_interrupt,
 	.dy_apicv_has_pending_interrupt = pi_has_pending_interrupt,
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index a3cca903154f..ede3b9f98243 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -1893,6 +1893,12 @@ void tdx_enable_smi_window(struct kvm_vcpu *vcpu)
 }
 #endif
 
+void tdx_set_virtual_apic_mode(struct kvm_vcpu *vcpu)
+{
+	/* Only x2APIC mode is supported for TD. */
+	WARN_ON_ONCE(kvm_get_apic_mode(vcpu) != LAPIC_MODE_X2APIC);
+}
+
 int tdx_get_cpl(struct kvm_vcpu *vcpu)
 {
 	return 0;
diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h
index 0c39fc4484a1..b339be6b5300 100644
--- a/arch/x86/kvm/vmx/x86_ops.h
+++ b/arch/x86/kvm/vmx/x86_ops.h
@@ -169,6 +169,7 @@ void tdx_get_exit_info(struct kvm_vcpu *vcpu, u32 *reason,
 bool tdx_has_emulated_msr(u32 index, bool write);
 int tdx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr);
 int tdx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr);
+void tdx_set_virtual_apic_mode(struct kvm_vcpu *vcpu);
 
 int tdx_get_cpl(struct kvm_vcpu *vcpu);
 void tdx_cache_reg(struct kvm_vcpu *vcpu, enum kvm_reg reg);
@@ -217,6 +218,8 @@ static inline bool tdx_has_emulated_msr(u32 index, bool write) { return false; }
 static inline int tdx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr) { return 1; }
 static inline int tdx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr) { return 1; }
 
+static inline void tdx_set_virtual_apic_mode(struct kvm_vcpu *vcpu) {}
+
 static inline int tdx_get_cpl(struct kvm_vcpu *vcpu) { return 0; }
 static inline void tdx_cache_reg(struct kvm_vcpu *vcpu, enum kvm_reg reg) {}
 static inline unsigned long tdx_get_rflags(struct kvm_vcpu *vcpu) { return 0; }
-- 
2.25.1