msix: Assert that specified vector is in range

There were several different ways to deal with the situation where the
vector specified for a msix function is out of bound:
- early return a function and keep progresssing
- propagate the error to the caller
- mark msix unusable
- assert it is in bound
- just ignore

An out-of-bound vector should not be specified if the device
implementation is correct so let msix functions always assert that the
specified vector is in range.

An exceptional case is virtio-pci, which allows the guest to configure
vectors. For virtio-pci, it is more appropriate to introduce its own
checks because it is sometimes too late to check the vector range in
msix functions.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-Id: <20220829083524.143640-1-akihiko.odaki@daynix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Yuval Shaia <yuval.shaia.ml@gmail.com>
Signed-off-by: Akihiko Odaki &lt;<a href="mailto:akihiko.odaki@daynix.com" target="_blank">akihiko.odaki@daynix.com</a>&gt;<br>

hw/net/e1000e.c

@@ -276,25 +276,18 @@ e1000e_unuse_msix_vectors(E1000EState *s, int num_vectors)
     }
 }
 
-static bool
+static void
 e1000e_use_msix_vectors(E1000EState *s, int num_vectors)
 {
     int i;
     for (i = 0; i < num_vectors; i++) {
-        int res = msix_vector_use(PCI_DEVICE(s), i);
-        if (res < 0) {
-            trace_e1000e_msix_use_vector_fail(i, res);
-            e1000e_unuse_msix_vectors(s, i);
-            return false;
-        }
+        msix_vector_use(PCI_DEVICE(s), i);
     }
-    return true;
 }
 
 static void
 e1000e_init_msix(E1000EState *s)
 {
-    PCIDevice *d = PCI_DEVICE(s);
     int res = msix_init(PCI_DEVICE(s), E1000E_MSIX_VEC_NUM,
                         &s->msix,
                         E1000E_MSIX_IDX, E1000E_MSIX_TABLE,
@@ -305,9 +298,7 @@ e1000e_init_msix(E1000EState *s)
     if (res < 0) {
         trace_e1000e_msix_init_fail(res);
     } else {
-        if (!e1000e_use_msix_vectors(s, E1000E_MSIX_VEC_NUM)) {
-            msix_uninit(d, &s->msix, &s->msix);
-        }
+        e1000e_use_msix_vectors(s, E1000E_MSIX_VEC_NUM);
     }
 }
 

hw/net/rocker/rocker.c

@@ -1212,24 +1212,14 @@ static void rocker_msix_vectors_unuse(Rocker *r,
     }
 }
 
-static int rocker_msix_vectors_use(Rocker *r,
-                                   unsigned int num_vectors)
+static void rocker_msix_vectors_use(Rocker *r, unsigned int num_vectors)
 {
     PCIDevice *dev = PCI_DEVICE(r);
-    int err;
     int i;
 
     for (i = 0; i < num_vectors; i++) {
-        err = msix_vector_use(dev, i);
-        if (err) {
-            goto rollback;
-        }
+        msix_vector_use(dev, i);
     }
-    return 0;
-
-rollback:
-    rocker_msix_vectors_unuse(r, i);
-    return err;
 }
 
 static int rocker_msix_init(Rocker *r, Error **errp)
@@ -1247,16 +1237,9 @@ static int rocker_msix_init(Rocker *r, Error **errp)
         return err;
     }
 
-    err = rocker_msix_vectors_use(r, ROCKER_MSIX_VEC_COUNT(r->fp_ports));
-    if (err) {
-        goto err_msix_vectors_use;
-    }
+    rocker_msix_vectors_use(r, ROCKER_MSIX_VEC_COUNT(r->fp_ports));
 
     return 0;
-
-err_msix_vectors_use:
-    msix_uninit(dev, &r->msix_bar, &r->msix_bar);
-    return err;
 }
 
 static void rocker_msix_uninit(Rocker *r)

hw/net/vmxnet3.c

@@ -2110,20 +2110,14 @@ vmxnet3_unuse_msix_vectors(VMXNET3State *s, int num_vectors)
     }
 }
 
-static bool
+static void
 vmxnet3_use_msix_vectors(VMXNET3State *s, int num_vectors)
 {
     PCIDevice *d = PCI_DEVICE(s);
     int i;
     for (i = 0; i < num_vectors; i++) {
-        int res = msix_vector_use(d, i);
-        if (0 > res) {
-            VMW_WRPRN("Failed to use MSI-X vector %d, error %d", i, res);
-            vmxnet3_unuse_msix_vectors(s, i);
-            return false;
-        }
+        msix_vector_use(d, i);
     }
-    return true;
 }
 
 static bool
@@ -2141,13 +2135,8 @@ vmxnet3_init_msix(VMXNET3State *s)
         VMW_WRPRN("Failed to initialize MSI-X, error %d", res);
         s->msix_used = false;
     } else {
-        if (!vmxnet3_use_msix_vectors(s, VMXNET3_MAX_INTRS)) {
-            VMW_WRPRN("Failed to use MSI-X vectors, error %d", res);
-            msix_uninit(d, &s->msix_bar, &s->msix_bar);
-            s->msix_used = false;
-        } else {
-            s->msix_used = true;
-        }
+        vmxnet3_use_msix_vectors(s, VMXNET3_MAX_INTRS);
+        s->msix_used = true;
     }
     return s->msix_used;
 }
@@ -2412,19 +2401,13 @@ static const VMStateDescription vmstate_vmxnet3_rxq_descr = {
 static int vmxnet3_post_load(void *opaque, int version_id)
 {
     VMXNET3State *s = opaque;
-    PCIDevice *d = PCI_DEVICE(s);
 
     net_tx_pkt_init(&s->tx_pkt, PCI_DEVICE(s),
                     s->max_tx_frags, s->peer_has_vhdr);
     net_rx_pkt_init(&s->rx_pkt, s->peer_has_vhdr);
 
     if (s->msix_used) {
-        if  (!vmxnet3_use_msix_vectors(s, VMXNET3_MAX_INTRS)) {
-            VMW_WRPRN("Failed to re-use MSI-X vectors");
-            msix_uninit(d, &s->msix_bar, &s->msix_bar);
-            s->msix_used = false;
-            return -1;
-        }
+        vmxnet3_use_msix_vectors(s, VMXNET3_MAX_INTRS);
     }
 
     if (!vmxnet3_validate_queues(s)) {

hw/nvme/ctrl.c

@@ -4744,11 +4744,8 @@ static void nvme_init_cq(NvmeCQueue *cq, NvmeCtrl *n, uint64_t dma_addr,
                          uint16_t cqid, uint16_t vector, uint16_t size,
                          uint16_t irq_enabled)
 {
-    int ret;
-
     if (msix_enabled(&n->parent_obj)) {
-        ret = msix_vector_use(&n->parent_obj, vector);
-        assert(ret == 0);
+        msix_vector_use(&n->parent_obj, vector);
     }
     cq->ctrl = n;
     cq->cqid = cqid;

hw/pci/msix.c

@@ -136,17 +136,12 @@ static void msix_handle_mask_update(PCIDevice *dev, int vector, bool was_masked)
     }
 }
 
-void msix_set_mask(PCIDevice *dev, int vector, bool mask, Error **errp)
+void msix_set_mask(PCIDevice *dev, int vector, bool mask)
 {
-    ERRP_GUARD();
     unsigned offset;
     bool was_masked;
 
-    if (vector > dev->msix_entries_nr) {
-        error_setg(errp, "msix: vector %d not allocated. max vector is %d",
-                   vector, dev->msix_entries_nr);
-        return;
-    }
+    assert(vector < dev->msix_entries_nr);
 
     offset = vector * PCI_MSIX_ENTRY_SIZE + PCI_MSIX_ENTRY_VECTOR_CTRL;
 
@@ -522,7 +517,9 @@ void msix_notify(PCIDevice *dev, unsigned vector)
 {
     MSIMessage msg;
 
-    if (vector >= dev->msix_entries_nr || !dev->msix_entry_used[vector]) {
+    assert(vector < dev->msix_entries_nr);
+
+    if (!dev->msix_entry_used[vector]) {
         return;
     }
 
@@ -558,20 +555,17 @@ void msix_reset(PCIDevice *dev)
  * don't want to follow the spec suggestion can declare all vectors as used. */
 
 /* Mark vector as used. */
-int msix_vector_use(PCIDevice *dev, unsigned vector)
+void msix_vector_use(PCIDevice *dev, unsigned vector)
 {
-    if (vector >= dev->msix_entries_nr) {
-        return -EINVAL;
-    }
-
+    assert(vector < dev->msix_entries_nr);
     dev->msix_entry_used[vector]++;
-    return 0;
 }
 
 /* Mark vector as unused. */
 void msix_vector_unuse(PCIDevice *dev, unsigned vector)
 {
-    if (vector >= dev->msix_entries_nr || !dev->msix_entry_used[vector]) {
+    assert(vector < dev->msix_entries_nr);
+    if (!dev->msix_entry_used[vector]) {
         return;
     }
     if (--dev->msix_entry_used[vector]) {

hw/rdma/vmw/pvrdma_main.c

@@ -307,12 +307,7 @@ static int init_msix(PCIDevice *pdev)
     }
 
     for (i = 0; i < RDMA_MAX_INTRS; i++) {
-        rc = msix_vector_use(PCI_DEVICE(dev), i);
-        if (rc < 0) {
-            rdma_error_report("Fail mark MSI-X vector %d", i);
-            uninit_msix(pdev, i);
-            return rc;
-        }
+        msix_vector_use(PCI_DEVICE(dev), i);
     }
 
     return 0;

hw/remote/vfio-user-obj.c

@@ -602,17 +602,10 @@ static void vfu_msix_irq_state(vfu_ctx_t *vfu_ctx, uint32_t start,
                                uint32_t count, bool mask)
 {
     VfuObject *o = vfu_get_private(vfu_ctx);
-    Error *err = NULL;
     uint32_t vector;
 
     for (vector = start; vector < count; vector++) {
-        msix_set_mask(o->pci_dev, vector, mask, &err);
-        if (err) {
-            VFU_OBJECT_ERROR(o, "vfu: %s: %s", o->device,
-                             error_get_pretty(err));
-            error_free(err);
-            err = NULL;
-        }
+        msix_set_mask(o->pci_dev, vector, mask);
     }
 }
 

hw/virtio/virtio-pci.c

@@ -71,9 +71,11 @@ static void virtio_pci_notify(DeviceState *d, uint16_t vector)
 {
     VirtIOPCIProxy *proxy = to_virtio_pci_proxy_fast(d);
 
-    if (msix_enabled(&proxy->pci_dev))
-        msix_notify(&proxy->pci_dev, vector);
-    else {
+    if (msix_enabled(&proxy->pci_dev)) {
+        if (vector != VIRTIO_NO_VECTOR) {
+            msix_notify(&proxy->pci_dev, vector);
+        }
+    } else {
         VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
         pci_set_irq(&proxy->pci_dev, qatomic_read(&vdev->isr) & 1);
     }
@@ -175,6 +177,7 @@ static int virtio_pci_load_config(DeviceState *d, QEMUFile *f)
 {
     VirtIOPCIProxy *proxy = to_virtio_pci_proxy(d);
     VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
+    uint16_t vector;
 
     int ret;
     ret = pci_device_load(&proxy->pci_dev, f);
@@ -184,12 +187,17 @@ static int virtio_pci_load_config(DeviceState *d, QEMUFile *f)
     msix_unuse_all_vectors(&proxy->pci_dev);
     msix_load(&proxy->pci_dev, f);
     if (msix_present(&proxy->pci_dev)) {
-        qemu_get_be16s(f, &vdev->config_vector);
+        qemu_get_be16s(f, &vector);
+
+        if (vector != VIRTIO_NO_VECTOR && vector >= proxy->nvectors) {
+            return -EINVAL;
+        }
     } else {
-        vdev->config_vector = VIRTIO_NO_VECTOR;
+        vector = VIRTIO_NO_VECTOR;
     }
-    if (vdev->config_vector != VIRTIO_NO_VECTOR) {
-        return msix_vector_use(&proxy->pci_dev, vdev->config_vector);
+    vdev->config_vector = vector;
+    if (vector != VIRTIO_NO_VECTOR) {
+        msix_vector_use(&proxy->pci_dev, vector);
     }
     return 0;
 }
@@ -202,12 +210,15 @@ static int virtio_pci_load_queue(DeviceState *d, int n, QEMUFile *f)
     uint16_t vector;
     if (msix_present(&proxy->pci_dev)) {
         qemu_get_be16s(f, &vector);
+        if (vector != VIRTIO_NO_VECTOR && vector >= proxy->nvectors) {
+            return -EINVAL;
+        }
     } else {
         vector = VIRTIO_NO_VECTOR;
     }
     virtio_queue_set_vector(vdev, n, vector);
     if (vector != VIRTIO_NO_VECTOR) {
-        return msix_vector_use(&proxy->pci_dev, vector);
+        msix_vector_use(&proxy->pci_dev, vector);
     }
 
     return 0;
@@ -299,6 +310,7 @@ static void virtio_ioport_write(void *opaque, uint32_t addr, uint32_t val)
 {
     VirtIOPCIProxy *proxy = opaque;
     VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
+    uint16_t vector;
     hwaddr pa;
 
     switch (addr) {
@@ -352,18 +364,28 @@ static void virtio_ioport_write(void *opaque, uint32_t addr, uint32_t val)
         }
         break;
     case VIRTIO_MSI_CONFIG_VECTOR:
-        msix_vector_unuse(&proxy->pci_dev, vdev->config_vector);
+        if (vdev->config_vector != VIRTIO_NO_VECTOR) {
+            msix_vector_unuse(&proxy->pci_dev, vdev->config_vector);
+        }
         /* Make it possible for guest to discover an error took place. */
-        if (msix_vector_use(&proxy->pci_dev, val) < 0)
+        if (val < proxy->nvectors) {
+            msix_vector_use(&proxy->pci_dev, val);
+        } else {
             val = VIRTIO_NO_VECTOR;
+        }
         vdev->config_vector = val;
         break;
     case VIRTIO_MSI_QUEUE_VECTOR:
-        msix_vector_unuse(&proxy->pci_dev,
-                          virtio_queue_vector(vdev, vdev->queue_sel));
+        vector = virtio_queue_vector(vdev, vdev->queue_sel);
+        if (vector != VIRTIO_NO_VECTOR) {
+            msix_vector_unuse(&proxy->pci_dev, vector);
+        }
         /* Make it possible for guest to discover an error took place. */
-        if (msix_vector_use(&proxy->pci_dev, val) < 0)
+        if (val < proxy->nvectors) {
+            msix_vector_use(&proxy->pci_dev, val);
+        } else {
             val = VIRTIO_NO_VECTOR;
+        }
         virtio_queue_set_vector(vdev, vdev->queue_sel, val);
         break;
     default:
@@ -1266,6 +1288,7 @@ static void virtio_pci_common_write(void *opaque, hwaddr addr,
 {
     VirtIOPCIProxy *proxy = opaque;
     VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
+    uint16_t vector;
 
     if (vdev == NULL) {
         return;
@@ -1287,9 +1310,13 @@ static void virtio_pci_common_write(void *opaque, hwaddr addr,
         }
         break;
     case VIRTIO_PCI_COMMON_MSIX:
-        msix_vector_unuse(&proxy->pci_dev, vdev->config_vector);
+        if (vdev->config_vector != VIRTIO_NO_VECTOR) {
+            msix_vector_unuse(&proxy->pci_dev, vdev->config_vector);
+        }
         /* Make it possible for guest to discover an error took place. */
-        if (msix_vector_use(&proxy->pci_dev, val) < 0) {
+        if (val < proxy->nvectors) {
+            msix_vector_use(&proxy->pci_dev, val);
+        } else {
             val = VIRTIO_NO_VECTOR;
         }
         vdev->config_vector = val;
@@ -1321,10 +1348,14 @@ static void virtio_pci_common_write(void *opaque, hwaddr addr,
                              proxy->vqs[vdev->queue_sel].num);
         break;
     case VIRTIO_PCI_COMMON_Q_MSIX:
-        msix_vector_unuse(&proxy->pci_dev,
-                          virtio_queue_vector(vdev, vdev->queue_sel));
+        vector = virtio_queue_vector(vdev, vdev->queue_sel);
+        if (vector != VIRTIO_NO_VECTOR) {
+            msix_vector_unuse(&proxy->pci_dev, vector);
+        }
         /* Make it possible for guest to discover an error took place. */
-        if (msix_vector_use(&proxy->pci_dev, val) < 0) {
+        if (val < proxy->nvectors) {
+            msix_vector_use(&proxy->pci_dev, val);
+        } else {
             val = VIRTIO_NO_VECTOR;
         }
         virtio_queue_set_vector(vdev, vdev->queue_sel, val);

include/hw/pci/msix.h

@@ -33,10 +33,10 @@ bool msix_is_masked(PCIDevice *dev, unsigned vector);
 void msix_set_pending(PCIDevice *dev, unsigned vector);
 void msix_clr_pending(PCIDevice *dev, int vector);
 
-int msix_vector_use(PCIDevice *dev, unsigned vector);
+void msix_vector_use(PCIDevice *dev, unsigned vector);
 void msix_vector_unuse(PCIDevice *dev, unsigned vector);
 void msix_unuse_all_vectors(PCIDevice *dev);
-void msix_set_mask(PCIDevice *dev, int vector, bool mask, Error **errp);
+void msix_set_mask(PCIDevice *dev, int vector, bool mask);
 
 void msix_notify(PCIDevice *dev, unsigned vector);