[PATCH 10/10] KVM: MSI to INTx translate

[Sheng Yang <sheng@linux.intel.com>]

Now we use MSI as default one, and translate MSI to INTx when guest need INTx
rather than MSI. For legacy device, we provide support for non-sharing host
IRQ.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
---
 virt/kvm/kvm_main.c |   52 ++++++++++++++++++++++++++++----------------------
 1 files changed, 29 insertions(+), 23 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 3ae8653..5aa975e 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -241,6 +241,8 @@ static int assigned_device_update_intx(struct kvm *kvm,
 			struct kvm_assigned_dev_kernel *adev,
 			struct kvm_assigned_irq *airq)
 {
+	BUG_ON(!!adev->irq_requested_type & KVM_ASSIGNED_DEV_HOST_MSI);
+
 	adev->guest_irq = airq->guest_irq;
 	adev->ack_notifier.gsi = airq->guest_irq;
 
@@ -248,11 +250,6 @@ static int assigned_device_update_intx(struct kvm *kvm,
 		return 0;
 
 	if (irqchip_in_kernel(kvm)) {
-		if (adev->irq_requested_type & KVM_ASSIGNED_DEV_HOST_MSI) {
-			free_irq(adev->host_irq, (void *)kvm);
-			pci_disable_msi(adev->dev);
-		}
-
 		if (!capable(CAP_SYS_RAWIO))
 			return -EPERM;
 
@@ -281,31 +278,32 @@ static int assigned_device_update_msi(struct kvm *kvm,
 			struct kvm_assigned_dev_kernel *adev,
 			struct kvm_assigned_irq *airq)
 {
-	int r;
+	BUG_ON(!!adev->irq_requested_type & KVM_ASSIGNED_DEV_HOST_INTX);
 
-	adev->guest_msi_addr = airq->guest_msi_addr;
-	adev->guest_msi_data = airq->guest_msi_data;
-	adev->ack_notifier.gsi = -1;
+	if (airq->flags & KVM_DEV_IRQ_ASSIGN_ENABLE_MSI) {
+		adev->irq_requested_type |= KVM_ASSIGNED_DEV_GUEST_MSI;
+		adev->irq_requested_type &= ~KVM_ASSIGNED_DEV_GUEST_INTX;
+		adev->guest_msi_addr = airq->guest_msi_addr;
+		adev->guest_msi_data = airq->guest_msi_data;
+		adev->ack_notifier.gsi = -1;
+	} else {
+		adev->irq_requested_type |= KVM_ASSIGNED_DEV_GUEST_INTX;
+		adev->irq_requested_type &= ~KVM_ASSIGNED_DEV_GUEST_MSI;
+		adev->guest_irq = airq->guest_irq;
+		adev->ack_notifier.gsi = airq->guest_irq;
+	}
 
 	if (adev->irq_requested_type & KVM_ASSIGNED_DEV_HOST_MSI)
 		return 0;
 
 	if (irqchip_in_kernel(kvm)) {
-		if (adev->irq_requested_type & KVM_ASSIGNED_DEV_HOST_INTX)
-			free_irq(adev->host_irq, (void *)adev);
-
-		r = pci_enable_msi(adev->dev);
-		if (r)
-			return r;
-
 		adev->host_irq = adev->dev->irq;
 		if (request_irq(adev->host_irq, kvm_assigned_dev_intr, 0,
 				"kvm_assigned_msi_device", (void *)adev))
 			return -EIO;
 	}
 
-	adev->irq_requested_type = KVM_ASSIGNED_DEV_GUEST_MSI |
-				   KVM_ASSIGNED_DEV_HOST_MSI;
+	adev->irq_requested_type |= KVM_ASSIGNED_DEV_HOST_MSI;
 	return 0;
 }
 #endif
@@ -343,11 +341,18 @@ static int kvm_vm_ioctl_assign_irq(struct kvm *kvm,
 				goto out_release;
 			else
 				match->irq_source_id = r;
+
+#ifdef CONFIG_X86
+			/* Determine host device irq type, we can know the
+			 * result from dev->msi_enabled */
+			pci_enable_msi(match->dev);
+#endif
 		}
 	}
 
-	if (assigned_irq->flags & KVM_DEV_IRQ_ASSIGN_ENABLE_MSI) {
+	if (match->dev->msi_enabled) {
 #ifdef CONFIG_X86
+		/* Device support MSI */
 		r = assigned_device_update_msi(kvm, match, assigned_irq);
 		if (r) {
 			printk(KERN_WARNING "kvm: failed to enable "
@@ -358,9 +363,10 @@ static int kvm_vm_ioctl_assign_irq(struct kvm *kvm,
 		r = -ENOTTY;
 #endif
 	} else if (assigned_irq->host_irq == 0 && match->dev->irq == 0) {
-		/* Host device IRQ 0 means don't support INTx */
-		printk(KERN_WARNING "kvm: wait device to enable MSI!\n");
-		r = 0;
+		/* Device only support MSI but can't enable */
+		printk(KERN_WARNING "kvm: failed to enable MSI device!\n");
+		r = -ENOTTY;
+		goto out_release;
 	} else {
 		/* Non-sharing INTx mode */
 		r = assigned_device_update_intx(kvm, match, assigned_irq);
-- 
1.5.4.5