vfio: fix interrupts race condition

[dpdk.git] / drivers / bus / pci / linux / pci_vfio.c

diff --git a/drivers/bus/pci/linux/pci_vfio.c b/drivers/bus/pci/linux/pci_vfio.c
index 1ceb1c0..ee31239 100644 (file)
--- a/drivers/bus/pci/linux/pci_vfio.c
+++ b/drivers/bus/pci/linux/pci_vfio.c
@@ -187,8 +187,11 @@ pci_vfio_set_bus_master(int dev_fd, bool op)
 static int
 pci_vfio_setup_interrupts(struct rte_pci_device *dev, int vfio_dev_fd)
 {
-       int i, ret, intr_idx;
+       char irq_set_buf[sizeof(struct vfio_irq_set) + sizeof(int)];
+       struct vfio_irq_set *irq_set;
        enum rte_intr_mode intr_mode;
+       int i, ret, intr_idx;
+       int fd;
 
        /* default to invalid index */
        intr_idx = VFIO_PCI_NUM_IRQS;
@@ -220,7 +223,6 @@ pci_vfio_setup_interrupts(struct rte_pci_device *dev, int vfio_dev_fd)
        /* start from MSI-X interrupt type */
        for (i = VFIO_PCI_MSIX_IRQ_INDEX; i >= 0; i--) {
                struct vfio_irq_info irq = { .argsz = sizeof(irq) };
-               int fd = -1;
 
                /* skip interrupt modes we don't want */
                if (intr_mode != RTE_INTR_MODE_NONE &&
@@ -236,51 +238,51 @@ pci_vfio_setup_interrupts(struct rte_pci_device *dev, int vfio_dev_fd)
                        return -1;
                }
 
+               /* found a usable interrupt mode */
+               if ((irq.flags & VFIO_IRQ_INFO_EVENTFD) != 0)
+                       break;
+
                /* if this vector cannot be used with eventfd, fail if we explicitly
                 * specified interrupt type, otherwise continue */
-               if ((irq.flags & VFIO_IRQ_INFO_EVENTFD) == 0) {
-                       if (intr_mode != RTE_INTR_MODE_NONE) {
-                               RTE_LOG(ERR, EAL,
-                                               "  interrupt vector does not support eventfd!\n");
-                               return -1;
-                       } else
-                               continue;
-               }
-
-               /* set up an eventfd for interrupts */
-               fd = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
-               if (fd < 0) {
-                       RTE_LOG(ERR, EAL, "  cannot set up eventfd, "
-                                       "error %i (%s)\n", errno, strerror(errno));
+               if (intr_mode != RTE_INTR_MODE_NONE) {
+                       RTE_LOG(ERR, EAL, "  interrupt vector does not support eventfd!\n");
                        return -1;
                }
+       }
 
-               dev->intr_handle.fd = fd;
-               dev->intr_handle.vfio_dev_fd = vfio_dev_fd;
+       if (i < 0)
+               return -1;
 
-               switch (i) {
-               case VFIO_PCI_MSIX_IRQ_INDEX:
-                       intr_mode = RTE_INTR_MODE_MSIX;
-                       dev->intr_handle.type = RTE_INTR_HANDLE_VFIO_MSIX;
-                       break;
-               case VFIO_PCI_MSI_IRQ_INDEX:
-                       intr_mode = RTE_INTR_MODE_MSI;
-                       dev->intr_handle.type = RTE_INTR_HANDLE_VFIO_MSI;
-                       break;
-               case VFIO_PCI_INTX_IRQ_INDEX:
-                       intr_mode = RTE_INTR_MODE_LEGACY;
-                       dev->intr_handle.type = RTE_INTR_HANDLE_VFIO_LEGACY;
-                       break;
-               default:
-                       RTE_LOG(ERR, EAL, "  unknown interrupt type!\n");
-                       return -1;
-               }
+       fd = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
+       if (fd < 0) {
+               RTE_LOG(ERR, EAL, "  cannot set up eventfd, error %i (%s)\n",
+                       errno, strerror(errno));
+               return -1;
+       }
 
-               return 0;
+       irq_set = (struct vfio_irq_set *)irq_set_buf;
+       irq_set->argsz = sizeof(irq_set_buf);
+       irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD|VFIO_IRQ_SET_ACTION_TRIGGER;
+       irq_set->index = i;
+       irq_set->start = 0;
+       irq_set->count = 1;
+       memcpy(&irq_set->data, &fd, sizeof(int));
+       if (ioctl(vfio_dev_fd, VFIO_DEVICE_SET_IRQS, irq_set) < 0) {
+               RTE_LOG(ERR, EAL, "  error configuring interrupt\n");
+               close(fd);
+               return -1;
        }
 
-       /* if we're here, we haven't found a suitable interrupt vector */
-       return -1;
+       dev->intr_handle.fd = fd;
+       dev->intr_handle.vfio_dev_fd = vfio_dev_fd;
+       if (i == VFIO_PCI_MSIX_IRQ_INDEX)
+               dev->intr_handle.type = RTE_INTR_HANDLE_VFIO_MSIX;
+       else if (i == VFIO_PCI_MSI_IRQ_INDEX)
+               dev->intr_handle.type = RTE_INTR_HANDLE_VFIO_MSI;
+       else if (i == VFIO_PCI_INTX_IRQ_INDEX)
+               dev->intr_handle.type = RTE_INTR_HANDLE_VFIO_LEGACY;
+
+       return 0;
 }
 
 #ifdef HAVE_VFIO_DEV_REQ_INTERFACE