KVM: Enable MSI for device assignment

We enable guest MSI and host MSI support in this patch. The userspace want to
enable MSI should set KVM_DEV_IRQ_ASSIGN_ENABLE_MSI in the assigned_irq's flag.
Function would return -ENOTTY if can't enable MSI, userspace shouldn't set MSI
Enable bit when KVM_ASSIGN_IRQ return -ENOTTY with
KVM_DEV_IRQ_ASSIGN_ENABLE_MSI.

Userspace can tell the support of MSI device from #ifdef KVM_CAP_DEVICE_MSI.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 75 insertions, 6 deletions

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 228c1d18a614..bf36ae9ae7df 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -159,9 +159,15 @@ static void kvm_assigned_dev_interrupt_work_handler(struct work_struct *work)
          * finer-grained lock, update this
          */
         mutex_lock(&assigned_dev->kvm->lock);
-        kvm_set_irq(assigned_dev->kvm,
-                    assigned_dev->irq_source_id,
-                    assigned_dev->guest_irq, 1);
+        if (assigned_dev->irq_requested_type & KVM_ASSIGNED_DEV_GUEST_INTX)
+                kvm_set_irq(assigned_dev->kvm,
+                            assigned_dev->irq_source_id,
+                            assigned_dev->guest_irq, 1);
+        else if (assigned_dev->irq_requested_type &
+                                KVM_ASSIGNED_DEV_GUEST_MSI) {
+                assigned_device_msi_dispatch(assigned_dev);
+                enable_irq(assigned_dev->host_irq);
+        }
         mutex_unlock(&assigned_dev->kvm->lock);
         kvm_put_kvm(assigned_dev->kvm);
 }
@@ -197,6 +203,8 @@ static void kvm_free_assigned_device(struct kvm *kvm,
 {
         if (irqchip_in_kernel(kvm) && assigned_dev->irq_requested_type)
                 free_irq(assigned_dev->host_irq, (void *)assigned_dev);
+        if (assigned_dev->irq_requested_type & KVM_ASSIGNED_DEV_HOST_MSI)
+                pci_disable_msi(assigned_dev->dev);
 
         kvm_unregister_irq_ack_notifier(&assigned_dev->ack_notifier);
         kvm_free_irq_source_id(kvm, assigned_dev->irq_source_id);
@@ -242,6 +250,11 @@ 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;
 
@@ -265,6 +278,41 @@ static int assigned_device_update_intx(struct kvm *kvm,
         return 0;
 }
 
+#ifdef CONFIG_X86
+static int assigned_device_update_msi(struct kvm *kvm,
+                        struct kvm_assigned_dev_kernel *adev,
+                        struct kvm_assigned_irq *airq)
+{
+        int r;
+
+        /* x86 don't care upper address of guest msi message addr */
+        adev->guest_msi.address_lo = airq->guest_msi.addr_lo;
+        adev->guest_msi.data = airq->guest_msi.data;
+        adev->ack_notifier.gsi = -1;
+
+        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;
+        return 0;
+}
+#endif
+
 static int kvm_vm_ioctl_assign_irq(struct kvm *kvm,
                                    struct kvm_assigned_irq
                                    *assigned_irq)
@@ -301,9 +349,30 @@ static int kvm_vm_ioctl_assign_irq(struct kvm *kvm,
                 }
         }
 
-        r = assigned_device_update_intx(kvm, match, assigned_irq);
-        if (r)
-                goto out_release;
+        if (assigned_irq->flags & KVM_DEV_IRQ_ASSIGN_ENABLE_MSI) {
+#ifdef CONFIG_X86
+                r = assigned_device_update_msi(kvm, match, assigned_irq);
+                if (r) {
+                        printk(KERN_WARNING "kvm: failed to enable "
+                                        "MSI device!\n");
+                        goto out_release;
+                }
+#else
+                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;
+        } else {
+                /* Non-sharing INTx mode */
+                r = assigned_device_update_intx(kvm, match, assigned_irq);
+                if (r) {
+                        printk(KERN_WARNING "kvm: failed to enable "
+                                        "INTx device!\n");
+                        goto out_release;
+                }
+        }
 
         mutex_unlock(&kvm->lock);
         return r;