[PATCH v2 13/17] KVM: TDX: Add methods to ignore virtual apic related operation

[Binbin Wu <binbin.wu@linux.intel.com>]

From: Isaku Yamahata <isaku.yamahata@intel.com>

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@intel.com>
Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com>
---
TDX interrupts v2:
- Rebased due to "Force APICv active for TDX guest", i.e.,
  vt_refresh_apicv_exec_ctrl() is moved to the patch
  "KVM: TDX: Force APICv active for TDX guest".
- Drop vt_hwapic_irr_update() since .hwapic_irr_update() is gone in 6.14.

TDX interrupts v1:
- Removed WARN_ON_ONCE() in tdx_set_virtual_apic_mode(). (Rick)
- Open code tdx_set_virtual_apic_mode(). (Binbin)
---
 arch/x86/kvm/vmx/main.c | 31 ++++++++++++++++++++++++++++---
 1 file changed, 28 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
index 7fa579c90991..9c173645928c 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -229,6 +229,15 @@ 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)
+{
+	/* Only x2APIC mode is supported for TD. */
+	if (is_td_vcpu(vcpu))
+		return;
+
+	return vmx_set_virtual_apic_mode(vcpu);
+}
+
 static void vt_apicv_pre_state_restore(struct kvm_vcpu *vcpu)
 {
 	struct pi_desc *pi = vcpu_to_pi_desc(vcpu);
@@ -237,6 +246,14 @@ static void vt_apicv_pre_state_restore(struct kvm_vcpu *vcpu)
 	memset(pi->pir, 0, sizeof(pi->pir));
 }
 
+static void vt_hwapic_isr_update(struct kvm_vcpu *vcpu, int max_isr)
+{
+	if (is_td_vcpu(vcpu))
+		return;
+
+	return vmx_hwapic_isr_update(vcpu, max_isr);
+}
+
 static int vt_sync_pir_to_irr(struct kvm_vcpu *vcpu)
 {
 	if (is_td_vcpu(vcpu))
@@ -426,6 +443,14 @@ static void vt_get_exit_info(struct kvm_vcpu *vcpu, u32 *reason,
 	vmx_get_exit_info(vcpu, reason, info1, info2, intr_info, error_code);
 }
 
+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 (is_td_vcpu(vcpu)) {
@@ -549,13 +574,13 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
 	.update_cr8_intercept = vmx_update_cr8_intercept,
 
 	.x2apic_icr_is_split = false,
-	.set_virtual_apic_mode = vmx_set_virtual_apic_mode,
-	.set_apic_access_page_addr = vmx_set_apic_access_page_addr,
+	.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 = vmx_load_eoi_exitmap,
 	.apicv_pre_state_restore = vt_apicv_pre_state_restore,
 	.required_apicv_inhibits = VMX_REQUIRED_APICV_INHIBITS,
-	.hwapic_isr_update = vmx_hwapic_isr_update,
+	.hwapic_isr_update = vt_hwapic_isr_update,
 	.sync_pir_to_irr = vt_sync_pir_to_irr,
 	.deliver_interrupt = vt_deliver_interrupt,
 	.dy_apicv_has_pending_interrupt = pi_has_pending_interrupt,
-- 
2.46.0