@@ -28,6 +28,7 @@ struct vfio_irq_eventfd {
msi_update_state(state, val, VFIO_PCI_MSI_STATE_EMPTY)
static void vfio_pci_disable_intx(struct kvm *kvm, struct vfio_device *vdev);
+static int vfio_pci_enable_intx(struct kvm *kvm, struct vfio_device *vdev);
static int vfio_pci_enable_msis(struct kvm *kvm, struct vfio_device *vdev,
bool msix)
@@ -50,17 +51,14 @@ static int vfio_pci_enable_msis(struct kvm *kvm, struct vfio_device *vdev,
if (!msi_is_enabled(msis->virt_state))
return 0;
- if (pdev->irq_modes & VFIO_PCI_IRQ_MODE_INTX) {
+ if (pdev->irq_modes & VFIO_PCI_IRQ_MODE_INTX)
/*
* PCI (and VFIO) forbids enabling INTx, MSI or MSIX at the same
* time. Since INTx has to be enabled from the start (we don't
- * have a reliable way to know when the user starts using it),
+ * have a reliable way to know when the guest starts using it),
* disable it now.
*/
vfio_pci_disable_intx(kvm, vdev);
- /* Permanently disable INTx */
- pdev->irq_modes &= ~VFIO_PCI_IRQ_MODE_INTX;
- }
eventfds = (void *)msis->irq_set + sizeof(struct vfio_irq_set);
@@ -162,7 +160,16 @@ static int vfio_pci_disable_msis(struct kvm *kvm, struct vfio_device *vdev,
msi_set_enabled(msis->phys_state, false);
msi_set_empty(msis->phys_state, true);
- return 0;
+ /*
+ * When MSI or MSIX is disabled, this might be called when
+ * PCI driver detects the MSI interrupt failure and wants to
+ * rollback to INTx mode. Thus enable INTx if the device
+ * supports INTx mode in this case.
+ */
+ if (pdev->irq_modes & VFIO_PCI_IRQ_MODE_INTX)
+ ret = vfio_pci_enable_intx(kvm, vdev);
+
+ return ret >= 0 ? 0 : ret;
}
static int vfio_pci_update_msi_entry(struct kvm *kvm, struct vfio_device *vdev,
@@ -1002,6 +1009,9 @@ static void vfio_pci_disable_intx(struct kvm *kvm, struct vfio_device *vdev)
.index = VFIO_PCI_INTX_IRQ_INDEX,
};
+ if (pdev->intx_fd == -1)
+ return;
+
pr_debug("user requested MSI, disabling INTx %d", gsi);
ioctl(vdev->fd, VFIO_DEVICE_SET_IRQS, &irq_set);
@@ -1009,6 +1019,7 @@ static void vfio_pci_disable_intx(struct kvm *kvm, struct vfio_device *vdev)
close(pdev->intx_fd);
close(pdev->unmask_fd);
+ pdev->intx_fd = -1;
}
static int vfio_pci_enable_intx(struct kvm *kvm, struct vfio_device *vdev)
@@ -1020,6 +1031,9 @@ static int vfio_pci_enable_intx(struct kvm *kvm, struct vfio_device *vdev)
struct vfio_pci_device *pdev = &vdev->pci;
int gsi = pdev->intx_gsi;
+ if (pdev->intx_fd != -1)
+ return 0;
+
/*
* PCI IRQ is level-triggered, so we use two eventfds. trigger_fd
* signals an interrupt from host to guest, and unmask_fd signals the
@@ -1122,6 +1136,8 @@ static int vfio_pci_init_intx(struct kvm *kvm, struct vfio_device *vdev)
/* Guest is going to ovewrite our irq_line... */
pdev->intx_gsi = pdev->hdr.irq_line - KVM_IRQ_OFFSET;
+ pdev->intx_fd = -1;
+
return 0;
}