[Qemu-devel] [PATCH v2] vfio/common: Introduce vfio_set_irq_signaling helper

[Eric Auger]

The code used to assign an interrupt index/subindex to an
eventfd is duplicated many times. Let's introduce an helper that
allows to set/unset the signaling for an ACTION_TRIGGER,
ACTION_MASK or ACTION_UNMASK action.

Signed-off-by: Eric Auger <address@hidden>

---

v1 -> v2:
- don't call GET_IRQ_INFO in vfio_set_irq_signaling()
  and restore quiet check in vfio_register_req_notifier.
  Nicer display of the IRQ name.

This is a follow-up to
[PATCH v2 0/2] vfio-pci: Introduce vfio_set_event_handler().
It looks to me that introducing vfio_set_irq_signaling() has more
benefits in term of code reduction and the helper abstraction
looks cleaner.
---
 hw/vfio/common.c              |  78 ++++++++++++
 hw/vfio/pci.c                 | 217 ++++++++--------------------------
 hw/vfio/platform.c            |  54 +++------
 include/hw/vfio/vfio-common.h |   2 +
 4 files changed, 150 insertions(+), 201 deletions(-)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 4374cc6176..1f1deff360 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -95,6 +95,84 @@ void vfio_mask_single_irqindex(VFIODevice *vbasedev, int 
index)
     ioctl(vbasedev->fd, VFIO_DEVICE_SET_IRQS, &irq_set);
 }
 
+static inline const char *action_to_str(int action)
+{
+    switch (action) {
+    case VFIO_IRQ_SET_ACTION_MASK:
+        return "MASK";
+    case VFIO_IRQ_SET_ACTION_UNMASK:
+        return "UNMASK";
+    case VFIO_IRQ_SET_ACTION_TRIGGER:
+        return "TRIGGER";
+    default:
+        return "UNKNOWN ACTION";
+    }
+}
+
+static char *irq_to_str(int index, int subindex)
+{
+    char *str;
+
+    switch (index) {
+    case VFIO_PCI_INTX_IRQ_INDEX:
+        str = g_strdup_printf("INTX-%d", subindex);
+        break;
+    case VFIO_PCI_MSI_IRQ_INDEX:
+        str = g_strdup_printf("MSI-%d", subindex);
+        break;
+    case VFIO_PCI_MSIX_IRQ_INDEX:
+        str = g_strdup_printf("MSIX-%d", subindex);
+        break;
+    case VFIO_PCI_ERR_IRQ_INDEX:
+        str = g_strdup_printf("ERR-%d", subindex);
+        break;
+    case VFIO_PCI_REQ_IRQ_INDEX:
+        str = g_strdup_printf("REQ-%d", subindex);
+        break;
+    default:
+        str = g_strdup_printf("index %d (unknown)", index);
+        break;
+    }
+    return str;
+}
+
+int vfio_set_irq_signaling(VFIODevice *vbasedev, int index, int subindex,
+                           int action, int fd, Error **errp)
+{
+    struct vfio_irq_set *irq_set;
+    int argsz, ret = 0;
+    int32_t *pfd;
+    char *irq_name;
+
+    argsz = sizeof(*irq_set) + sizeof(*pfd);
+
+    irq_set = g_malloc0(argsz);
+    irq_set->argsz = argsz;
+    irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD | action;
+    irq_set->index = index;
+    irq_set->start = subindex;
+    irq_set->count = 1;
+    pfd = (int32_t *)&irq_set->data;
+    *pfd = fd;
+
+    ret = ioctl(vbasedev->fd, VFIO_DEVICE_SET_IRQS, irq_set);
+
+    g_free(irq_set);
+
+    if (!ret) {
+        return 0;
+    }
+
+    error_setg_errno(errp, -ret, "VFIO_DEVICE_SET_IRQS failure");
+    irq_name = irq_to_str(index, subindex);
+    error_prepend(errp,
+                  "Failed to %s %s eventfd signaling for interrupt %s: ",
+                  fd < 0 ? "tear down" : "set up", action_to_str(action),
+                  irq_name);
+    g_free(irq_name);
+    return ret;
+}
+
 /*
  * IO Port/MMIO - Beware of the endians, VFIO is always little endian
  */
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 8cecb53d5c..e42901bd66 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -113,9 +113,7 @@ static void vfio_intx_enable_kvm(VFIOPCIDevice *vdev, Error 
**errp)
         .gsi = vdev->intx.route.irq,
         .flags = KVM_IRQFD_FLAG_RESAMPLE,
     };
-    struct vfio_irq_set *irq_set;
-    int ret, argsz;
-    int32_t *pfd;
+    Error *err = NULL;
 
     if (vdev->no_kvm_intx || !kvm_irqfds_enabled() ||
         vdev->intx.route.mode != PCI_INTX_ENABLED ||
@@ -143,22 +141,10 @@ static void vfio_intx_enable_kvm(VFIOPCIDevice *vdev, 
Error **errp)
         goto fail_irqfd;
     }
 
-    argsz = sizeof(*irq_set) + sizeof(*pfd);
-
-    irq_set = g_malloc0(argsz);
-    irq_set->argsz = argsz;
-    irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_UNMASK;
-    irq_set->index = VFIO_PCI_INTX_IRQ_INDEX;
-    irq_set->start = 0;
-    irq_set->count = 1;
-    pfd = (int32_t *)&irq_set->data;
-
-    *pfd = irqfd.resamplefd;
-
-    ret = ioctl(vdev->vbasedev.fd, VFIO_DEVICE_SET_IRQS, irq_set);
-    g_free(irq_set);
-    if (ret) {
-        error_setg_errno(errp, -ret, "failed to setup INTx unmask fd");
+    if (vfio_set_irq_signaling(&vdev->vbasedev, VFIO_PCI_INTX_IRQ_INDEX, 0,
+                               VFIO_IRQ_SET_ACTION_UNMASK,
+                               irqfd.resamplefd, &err)) {
+        error_propagate(errp, err);
         goto fail_vfio;
     }
 
@@ -262,10 +248,10 @@ static void vfio_intx_update(PCIDevice *pdev)
 static int vfio_intx_enable(VFIOPCIDevice *vdev, Error **errp)
 {
     uint8_t pin = vfio_pci_read_config(&vdev->pdev, PCI_INTERRUPT_PIN, 1);
-    int ret, argsz, retval = 0;
-    struct vfio_irq_set *irq_set;
-    int32_t *pfd;
     Error *err = NULL;
+    int32_t fd;
+    int ret;
+
 
     if (!pin) {
         return 0;
@@ -292,27 +278,15 @@ static int vfio_intx_enable(VFIOPCIDevice *vdev, Error 
**errp)
         error_setg_errno(errp, -ret, "event_notifier_init failed");
         return ret;
     }
+    fd = event_notifier_get_fd(&vdev->intx.interrupt);
+    qemu_set_fd_handler(fd, vfio_intx_interrupt, NULL, vdev);
 
-    argsz = sizeof(*irq_set) + sizeof(*pfd);
-
-    irq_set = g_malloc0(argsz);
-    irq_set->argsz = argsz;
-    irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_TRIGGER;
-    irq_set->index = VFIO_PCI_INTX_IRQ_INDEX;
-    irq_set->start = 0;
-    irq_set->count = 1;
-    pfd = (int32_t *)&irq_set->data;
-
-    *pfd = event_notifier_get_fd(&vdev->intx.interrupt);
-    qemu_set_fd_handler(*pfd, vfio_intx_interrupt, NULL, vdev);
-
-    ret = ioctl(vdev->vbasedev.fd, VFIO_DEVICE_SET_IRQS, irq_set);
-    if (ret) {
-        error_setg_errno(errp, -ret, "failed to setup INTx fd");
-        qemu_set_fd_handler(*pfd, NULL, NULL, vdev);
+    if (vfio_set_irq_signaling(&vdev->vbasedev, VFIO_PCI_INTX_IRQ_INDEX, 0,
+                               VFIO_IRQ_SET_ACTION_TRIGGER, fd, &err)) {
+        error_propagate(errp, err);
+        qemu_set_fd_handler(fd, NULL, NULL, vdev);
         event_notifier_cleanup(&vdev->intx.interrupt);
-        retval = -errno;
-        goto cleanup;
+        return -errno;
     }
 
     vfio_intx_enable_kvm(vdev, &err);
@@ -323,11 +297,7 @@ static int vfio_intx_enable(VFIOPCIDevice *vdev, Error 
**errp)
     vdev->interrupt = VFIO_INT_INTx;
 
     trace_vfio_intx_enable(vdev->vbasedev.name);
-
-cleanup:
-    g_free(irq_set);
-
-    return retval;
+    return 0;
 }
 
 static void vfio_intx_disable(VFIOPCIDevice *vdev)
@@ -530,31 +500,19 @@ static int vfio_msix_vector_do_use(PCIDevice *pdev, 
unsigned int nr,
             error_report("vfio: failed to enable vectors, %d", ret);
         }
     } else {
-        int argsz;
-        struct vfio_irq_set *irq_set;
-        int32_t *pfd;
-
-        argsz = sizeof(*irq_set) + sizeof(*pfd);
-
-        irq_set = g_malloc0(argsz);
-        irq_set->argsz = argsz;
-        irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD |
-                         VFIO_IRQ_SET_ACTION_TRIGGER;
-        irq_set->index = VFIO_PCI_MSIX_IRQ_INDEX;
-        irq_set->start = nr;
-        irq_set->count = 1;
-        pfd = (int32_t *)&irq_set->data;
+        Error *err = NULL;
+        int32_t fd;
 
         if (vector->virq >= 0) {
-            *pfd = event_notifier_get_fd(&vector->kvm_interrupt);
+            fd = event_notifier_get_fd(&vector->kvm_interrupt);
         } else {
-            *pfd = event_notifier_get_fd(&vector->interrupt);
+            fd = event_notifier_get_fd(&vector->interrupt);
         }
 
-        ret = ioctl(vdev->vbasedev.fd, VFIO_DEVICE_SET_IRQS, irq_set);
-        g_free(irq_set);
-        if (ret) {
-            error_report("vfio: failed to modify vector, %d", ret);
+        if (vfio_set_irq_signaling(&vdev->vbasedev,
+                                     VFIO_PCI_MSIX_IRQ_INDEX, nr,
+                                     VFIO_IRQ_SET_ACTION_TRIGGER, fd, &err)) {
+            error_reportf_err(err, VFIO_MSG_PREFIX, vdev->vbasedev.name);
         }
     }
 
@@ -591,26 +549,10 @@ static void vfio_msix_vector_release(PCIDevice *pdev, 
unsigned int nr)
      * be re-asserted on unmask.  Nothing to do if already using QEMU mode.
      */
     if (vector->virq >= 0) {
-        int argsz;
-        struct vfio_irq_set *irq_set;
-        int32_t *pfd;
+        int32_t fd = event_notifier_get_fd(&vector->interrupt);
 
-        argsz = sizeof(*irq_set) + sizeof(*pfd);
-
-        irq_set = g_malloc0(argsz);
-        irq_set->argsz = argsz;
-        irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD |
-                         VFIO_IRQ_SET_ACTION_TRIGGER;
-        irq_set->index = VFIO_PCI_MSIX_IRQ_INDEX;
-        irq_set->start = nr;
-        irq_set->count = 1;
-        pfd = (int32_t *)&irq_set->data;
-
-        *pfd = event_notifier_get_fd(&vector->interrupt);
-
-        ioctl(vdev->vbasedev.fd, VFIO_DEVICE_SET_IRQS, irq_set);
-
-        g_free(irq_set);
+        vfio_set_irq_signaling(&vdev->vbasedev, VFIO_PCI_MSIX_IRQ_INDEX, nr,
+                               VFIO_IRQ_SET_ACTION_TRIGGER, fd, NULL);
     }
 }
 
@@ -2636,10 +2578,8 @@ static void vfio_err_notifier_handler(void *opaque)
  */
 static void vfio_register_err_notifier(VFIOPCIDevice *vdev)
 {
-    int ret;
-    int argsz;
-    struct vfio_irq_set *irq_set;
-    int32_t *pfd;
+    Error *err = NULL;
+    int32_t fd;
 
     if (!vdev->pci_aer) {
         return;
@@ -2651,58 +2591,30 @@ static void vfio_register_err_notifier(VFIOPCIDevice 
*vdev)
         return;
     }
 
-    argsz = sizeof(*irq_set) + sizeof(*pfd);
+    fd = event_notifier_get_fd(&vdev->err_notifier);
+    qemu_set_fd_handler(fd, vfio_err_notifier_handler, NULL, vdev);
 
-    irq_set = g_malloc0(argsz);
-    irq_set->argsz = argsz;
-    irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD |
-                     VFIO_IRQ_SET_ACTION_TRIGGER;
-    irq_set->index = VFIO_PCI_ERR_IRQ_INDEX;
-    irq_set->start = 0;
-    irq_set->count = 1;
-    pfd = (int32_t *)&irq_set->data;
-
-    *pfd = event_notifier_get_fd(&vdev->err_notifier);
-    qemu_set_fd_handler(*pfd, vfio_err_notifier_handler, NULL, vdev);
-
-    ret = ioctl(vdev->vbasedev.fd, VFIO_DEVICE_SET_IRQS, irq_set);
-    if (ret) {
-        error_report("vfio: Failed to set up error notification");
-        qemu_set_fd_handler(*pfd, NULL, NULL, vdev);
+    if (vfio_set_irq_signaling(&vdev->vbasedev, VFIO_PCI_ERR_IRQ_INDEX, 0,
+                               VFIO_IRQ_SET_ACTION_TRIGGER, fd, &err)) {
+        error_reportf_err(err, VFIO_MSG_PREFIX, vdev->vbasedev.name);
+        qemu_set_fd_handler(fd, NULL, NULL, vdev);
         event_notifier_cleanup(&vdev->err_notifier);
         vdev->pci_aer = false;
     }
-    g_free(irq_set);
 }
 
 static void vfio_unregister_err_notifier(VFIOPCIDevice *vdev)
 {
-    int argsz;
-    struct vfio_irq_set *irq_set;
-    int32_t *pfd;
-    int ret;
+    Error *err = NULL;
 
     if (!vdev->pci_aer) {
         return;
     }
 
-    argsz = sizeof(*irq_set) + sizeof(*pfd);
-
-    irq_set = g_malloc0(argsz);
-    irq_set->argsz = argsz;
-    irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD |
-                     VFIO_IRQ_SET_ACTION_TRIGGER;
-    irq_set->index = VFIO_PCI_ERR_IRQ_INDEX;
-    irq_set->start = 0;
-    irq_set->count = 1;
-    pfd = (int32_t *)&irq_set->data;
-    *pfd = -1;
-
-    ret = ioctl(vdev->vbasedev.fd, VFIO_DEVICE_SET_IRQS, irq_set);
-    if (ret) {
-        error_report("vfio: Failed to de-assign error fd: %m");
+    if (vfio_set_irq_signaling(&vdev->vbasedev, VFIO_PCI_ERR_IRQ_INDEX, 0,
+                               VFIO_IRQ_SET_ACTION_TRIGGER, -1, &err)) {
+        error_reportf_err(err, VFIO_MSG_PREFIX, vdev->vbasedev.name);
     }
-    g_free(irq_set);
     qemu_set_fd_handler(event_notifier_get_fd(&vdev->err_notifier),
                         NULL, NULL, vdev);
     event_notifier_cleanup(&vdev->err_notifier);
@@ -2727,9 +2639,8 @@ static void vfio_register_req_notifier(VFIOPCIDevice 
*vdev)
 {
     struct vfio_irq_info irq_info = { .argsz = sizeof(irq_info),
                                       .index = VFIO_PCI_REQ_IRQ_INDEX };
-    int argsz;
-    struct vfio_irq_set *irq_set;
-    int32_t *pfd;
+    Error *err = NULL;
+    int32_t fd;
 
     if (!(vdev->features & VFIO_FEATURE_ENABLE_REQ)) {
         return;
@@ -2745,57 +2656,31 @@ static void vfio_register_req_notifier(VFIOPCIDevice 
*vdev)
         return;
     }
 
-    argsz = sizeof(*irq_set) + sizeof(*pfd);
+    fd = event_notifier_get_fd(&vdev->req_notifier);
+    qemu_set_fd_handler(fd, vfio_req_notifier_handler, NULL, vdev);
 
-    irq_set = g_malloc0(argsz);
-    irq_set->argsz = argsz;
-    irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD |
-                     VFIO_IRQ_SET_ACTION_TRIGGER;
-    irq_set->index = VFIO_PCI_REQ_IRQ_INDEX;
-    irq_set->start = 0;
-    irq_set->count = 1;
-    pfd = (int32_t *)&irq_set->data;
-
-    *pfd = event_notifier_get_fd(&vdev->req_notifier);
-    qemu_set_fd_handler(*pfd, vfio_req_notifier_handler, NULL, vdev);
-
-    if (ioctl(vdev->vbasedev.fd, VFIO_DEVICE_SET_IRQS, irq_set)) {
-        error_report("vfio: Failed to set up device request notification");
-        qemu_set_fd_handler(*pfd, NULL, NULL, vdev);
+    if (vfio_set_irq_signaling(&vdev->vbasedev, VFIO_PCI_REQ_IRQ_INDEX, 0,
+                           VFIO_IRQ_SET_ACTION_TRIGGER, fd, &err)) {
+        error_reportf_err(err, VFIO_MSG_PREFIX, vdev->vbasedev.name);
+        qemu_set_fd_handler(fd, NULL, NULL, vdev);
         event_notifier_cleanup(&vdev->req_notifier);
     } else {
         vdev->req_enabled = true;
     }
-
-    g_free(irq_set);
 }
 
 static void vfio_unregister_req_notifier(VFIOPCIDevice *vdev)
 {
-    int argsz;
-    struct vfio_irq_set *irq_set;
-    int32_t *pfd;
+    Error *err = NULL;
 
     if (!vdev->req_enabled) {
         return;
     }
 
-    argsz = sizeof(*irq_set) + sizeof(*pfd);
-
-    irq_set = g_malloc0(argsz);
-    irq_set->argsz = argsz;
-    irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD |
-                     VFIO_IRQ_SET_ACTION_TRIGGER;
-    irq_set->index = VFIO_PCI_REQ_IRQ_INDEX;
-    irq_set->start = 0;
-    irq_set->count = 1;
-    pfd = (int32_t *)&irq_set->data;
-    *pfd = -1;
-
-    if (ioctl(vdev->vbasedev.fd, VFIO_DEVICE_SET_IRQS, irq_set)) {
-        error_report("vfio: Failed to de-assign device request fd: %m");
+    if (vfio_set_irq_signaling(&vdev->vbasedev, VFIO_PCI_REQ_IRQ_INDEX, 0,
+                               VFIO_IRQ_SET_ACTION_TRIGGER, -1, &err)) {
+        error_reportf_err(err, VFIO_MSG_PREFIX, vdev->vbasedev.name);
     }
-    g_free(irq_set);
     qemu_set_fd_handler(event_notifier_get_fd(&vdev->req_notifier),
                         NULL, NULL, vdev);
     event_notifier_cleanup(&vdev->req_notifier);
diff --git a/hw/vfio/platform.c b/hw/vfio/platform.c
index 398db38f14..6e64d42c96 100644
--- a/hw/vfio/platform.c
+++ b/hw/vfio/platform.c
@@ -106,26 +106,19 @@ static int vfio_set_trigger_eventfd(VFIOINTp *intp,
                                     eventfd_user_side_handler_t handler)
 {
     VFIODevice *vbasedev = &intp->vdev->vbasedev;
-    struct vfio_irq_set *irq_set;
-    int argsz, ret;
-    int32_t *pfd;
+    int32_t fd = event_notifier_get_fd(intp->interrupt);
+    Error *err = NULL;
+    int ret;
 
-    argsz = sizeof(*irq_set) + sizeof(*pfd);
-    irq_set = g_malloc0(argsz);
-    irq_set->argsz = argsz;
-    irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_TRIGGER;
-    irq_set->index = intp->pin;
-    irq_set->start = 0;
-    irq_set->count = 1;
-    pfd = (int32_t *)&irq_set->data;
-    *pfd = event_notifier_get_fd(intp->interrupt);
-    qemu_set_fd_handler(*pfd, (IOHandler *)handler, NULL, intp);
-    ret = ioctl(vbasedev->fd, VFIO_DEVICE_SET_IRQS, irq_set);
-    if (ret < 0) {
-        error_report("vfio: Failed to set trigger eventfd: %m");
-        qemu_set_fd_handler(*pfd, NULL, NULL, NULL);
+    qemu_set_fd_handler(fd, (IOHandler *)handler, NULL, intp);
+
+    ret = vfio_set_irq_signaling(vbasedev, intp->pin, 0,
+                                 VFIO_IRQ_SET_ACTION_TRIGGER, fd, &err);
+    if (ret) {
+        error_reportf_err(err, VFIO_MSG_PREFIX, vbasedev->name);
+        qemu_set_fd_handler(fd, NULL, NULL, NULL);
     }
-    g_free(irq_set);
+
     return ret;
 }
 
@@ -361,25 +354,16 @@ static void vfio_start_eventfd_injection(SysBusDevice 
*sbdev, qemu_irq irq)
  */
 static int vfio_set_resample_eventfd(VFIOINTp *intp)
 {
+    int32_t fd = event_notifier_get_fd(intp->unmask);
     VFIODevice *vbasedev = &intp->vdev->vbasedev;
-    struct vfio_irq_set *irq_set;
-    int argsz, ret;
-    int32_t *pfd;
+    Error *err = NULL;
+    int ret;
 
-    argsz = sizeof(*irq_set) + sizeof(*pfd);
-    irq_set = g_malloc0(argsz);
-    irq_set->argsz = argsz;
-    irq_set->flags = VFIO_IRQ_SET_DATA_EVENTFD | VFIO_IRQ_SET_ACTION_UNMASK;
-    irq_set->index = intp->pin;
-    irq_set->start = 0;
-    irq_set->count = 1;
-    pfd = (int32_t *)&irq_set->data;
-    *pfd = event_notifier_get_fd(intp->unmask);
-    qemu_set_fd_handler(*pfd, NULL, NULL, NULL);
-    ret = ioctl(vbasedev->fd, VFIO_DEVICE_SET_IRQS, irq_set);
-    g_free(irq_set);
-    if (ret < 0) {
-        error_report("vfio: Failed to set resample eventfd: %m");
+    qemu_set_fd_handler(fd, NULL, NULL, NULL);
+    ret = vfio_set_irq_signaling(vbasedev, intp->pin, 0,
+                                 VFIO_IRQ_SET_ACTION_UNMASK, fd, &err);
+    if (ret) {
+        error_reportf_err(err, VFIO_MSG_PREFIX, vbasedev->name);
     }
     return ret;
 }
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index 1155b79678..686d99ff8c 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -167,6 +167,8 @@ void vfio_put_base_device(VFIODevice *vbasedev);
 void vfio_disable_irqindex(VFIODevice *vbasedev, int index);
 void vfio_unmask_single_irqindex(VFIODevice *vbasedev, int index);
 void vfio_mask_single_irqindex(VFIODevice *vbasedev, int index);
+int vfio_set_irq_signaling(VFIODevice *vbasedev, int index, int subindex,
+                           int action, int fd, Error **errp);
 void vfio_region_write(void *opaque, hwaddr addr,
                            uint64_t data, unsigned size);
 uint64_t vfio_region_read(void *opaque,
-- 
2.20.1