On 06/08/21 12:07, Hikaru Nishida wrote:

+#if defined(CONFIG_KVM_VIRT_SUSPEND_TIMING) || \
+	defined(CONFIG_KVM_VIRT_SUSPEND_TIMING_GUEST)
+#define VIRT_SUSPEND_TIMING_VECTOR	0xec
+#endif

No need to use a new vector.  You can rename the existing 
MSR_KVM_ASYNC_PF_INT to MSR_KVM_HYPERVISOR_CALLBACK_INT or something 
like that, and add the code to sysvec_kvm_asyncpf_interrupt.

+static void kvm_make_suspend_time_interrupt(struct kvm_vcpu *vcpu)
+{
+	kvm_queue_interrupt(vcpu, VIRT_SUSPEND_TIMING_VECTOR, false);
+	kvm_make_request(KVM_REQ_EVENT, vcpu);
+}

Use kvm_apic_set_irq which will inject the interrupt as soon as 
possible, so you do not even need to check 
kvm_vcpu_ready_for_interrupt_injection.

+#ifdef CONFIG_KVM_VIRT_SUSPEND_TIMING
+		if (kvm->suspend_injection_requested &&
+			kvm_vcpu_ready_for_interrupt_injection(vcpu)) {
+			kvm_write_suspend_time(kvm);
+			kvm_make_suspend_time_interrupt(vcpu);
+			kvm->suspend_injection_requested = false;
+		}
+#endif

Do not read variables in vcpu_run; There is KVM_REQ_* if you need to do 
work in the vCPU run loop.

+	mutex_lock(&kvm_lock);
+	list_for_each_entry(kvm, &vm_list, vm_list) {
+		if (!(kvm->arch.msr_suspend_time & KVM_MSR_ENABLED))
+			continue;
+
+		kvm_for_each_vcpu(i, vcpu, kvm)
+			vcpu->arch.tsc_offset_adjustment -= adj;
+
+		/*
+		 * Move the offset of kvm_clock here as if it is stopped
+		 * during the suspension.
+		 */
+		kvm->arch.kvmclock_offset -= suspend_time_ns;
+
+		/* suspend_time is accumulated per VM. */
+		kvm->suspend_time_ns += suspend_time_ns;
+		kvm->suspend_injection_requested = true;
+		/*
+		 * This adjustment will be reflected to the struct provided
+		 * from the guest via MSR_KVM_HOST_SUSPEND_TIME before
+		 * the notification interrupt is injected.
+		 */
+	}
+	mutex_unlock(&kvm_lock);
+}

As pointed out by Thomas, this should be a work item.

Paolo