[PATCH v2 09/15] svm: Add support for activate/deactivate AVIC at runtime

["Suthikulpanit, Suravee" <Suravee.Suthikulpanit@xxxxxxx>]

Add necessary logics for supporting activate/deactivate AVIC at runtime.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
---
 arch/x86/kvm/svm.c | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 47f2439..cfa4b13 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -385,6 +385,7 @@ struct amd_svm_iommu_ir {
 static void svm_flush_tlb(struct kvm_vcpu *vcpu, bool invalidate_gpa);
 static void svm_complete_interrupts(struct vcpu_svm *svm);
 static bool svm_get_enable_apicv(struct kvm *kvm);
+static inline void avic_post_state_restore(struct kvm_vcpu *vcpu);
 
 static int nested_svm_exit_handled(struct vcpu_svm *svm);
 static int nested_svm_intercept(struct vcpu_svm *svm);
@@ -2343,6 +2344,10 @@ static void svm_vcpu_blocking(struct kvm_vcpu *vcpu)
 
 static void svm_vcpu_unblocking(struct kvm_vcpu *vcpu)
 {
+	if (kvm_check_request(KVM_REQ_APICV_ACTIVATE, vcpu))
+		kvm_vcpu_activate_apicv(vcpu);
+	if (kvm_check_request(KVM_REQ_APICV_DEACTIVATE, vcpu))
+		kvm_vcpu_deactivate_apicv(vcpu);
 	avic_set_running(vcpu, true);
 }
 
@@ -5182,10 +5187,19 @@ static void svm_refresh_apicv_exec_ctrl(struct kvm_vcpu *vcpu)
 	struct vcpu_svm *svm = to_svm(vcpu);
 	struct vmcb *vmcb = svm->vmcb;
 
-	if (kvm_vcpu_apicv_active(vcpu))
+	if (kvm_vcpu_apicv_active(vcpu)) {
+		/**
+		 * During AVIC temporary deactivation, guest could update
+		 * APIC ID, DFR and LDR registers, which would not be trapped
+		 * by avic_unaccelerated_ccess_interception(). In this case,
+		 * we need to check and update the AVIC logical APIC ID table
+		 * accordingly before re-activating.
+		 */
+		avic_post_state_restore(vcpu);
 		vmcb->control.int_ctl |= AVIC_ENABLE_MASK;
-	else
+	} else {
 		vmcb->control.int_ctl &= ~AVIC_ENABLE_MASK;
+	}
 	mark_dirty(vmcb, VMCB_AVIC);
 }
 
@@ -7229,6 +7243,14 @@ static bool svm_need_emulation_on_page_fault(struct kvm_vcpu *vcpu)
 	return false;
 }
 
+static void svm_pre_update_apicv_exec_ctrl(struct kvm_vcpu *vcpu, bool activate)
+{
+	if (activate)
+		avic_setup_access_page(vcpu, false);
+	else
+		avic_destroy_access_page(vcpu);
+}
+
 static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
 	.cpu_has_kvm_support = has_svm,
 	.disabled_by_bios = is_disabled,
@@ -7306,6 +7328,7 @@ static bool svm_need_emulation_on_page_fault(struct kvm_vcpu *vcpu)
 	.set_virtual_apic_mode = svm_set_virtual_apic_mode,
 	.get_enable_apicv = svm_get_enable_apicv,
 	.refresh_apicv_exec_ctrl = svm_refresh_apicv_exec_ctrl,
+	.pre_update_apicv_exec_ctrl = svm_pre_update_apicv_exec_ctrl,
 	.load_eoi_exitmap = svm_load_eoi_exitmap,
 	.hwapic_irr_update = svm_hwapic_irr_update,
 	.hwapic_isr_update = svm_hwapic_isr_update,
-- 
1.8.3.1