[Qemu-devel] [PATCH v6 08/16] virtio: introduce bus specific queue limit

[Jason Wang <jasowang@redhat.com>]

This patch introduces a bus specific queue limitation. It will be
useful for increasing the limit for one of the bus without disturbing
other buses.

Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Alexander Graf <agraf@suse.de>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 hw/char/virtio-serial-bus.c    |  2 +-
 hw/net/virtio-net.c            |  4 ++--
 hw/s390x/s390-virtio-bus.c     |  1 +
 hw/s390x/virtio-ccw.c          |  1 +
 hw/scsi/virtio-scsi.c          |  4 ++--
 hw/virtio/virtio-mmio.c        |  1 +
 hw/virtio/virtio-pci.c         |  1 +
 hw/virtio/virtio.c             | 40 +++++++++++++++++++++++++---------------
 include/hw/virtio/virtio-bus.h |  1 +
 include/hw/virtio/virtio.h     |  1 +
 10 files changed, 36 insertions(+), 20 deletions(-)

diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c
index e336bdb..0694831 100644
--- a/hw/char/virtio-serial-bus.c
+++ b/hw/char/virtio-serial-bus.c
@@ -973,7 +973,7 @@ static void virtio_serial_device_realize(DeviceState *dev, Error **errp)
     }
 
     /* Each port takes 2 queues, and one pair is for the control queue */
-    max_supported_ports = VIRTIO_PCI_QUEUE_MAX / 2 - 1;
+    max_supported_ports = virtio_get_queue_max(vdev) / 2 - 1;
 
     if (vser->serial.max_virtserial_ports > max_supported_ports) {
         error_setg(errp, "maximum ports supported: %u", max_supported_ports);
diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index b6fac9c..bf286f5 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -1588,10 +1588,10 @@ static void virtio_net_device_realize(DeviceState *dev, Error **errp)
     virtio_init(vdev, "virtio-net", VIRTIO_ID_NET, n->config_size);
 
     n->max_queues = MAX(n->nic_conf.peers.queues, 1);
-    if (n->max_queues * 2 + 1 > VIRTIO_PCI_QUEUE_MAX) {
+    if (n->max_queues * 2 + 1 > virtio_get_queue_max(vdev)) {
         error_setg(errp, "Invalid number of queues (= %" PRIu32 "), "
                    "must be a postive integer less than %d.",
-                   n->max_queues, (VIRTIO_PCI_QUEUE_MAX - 1) / 2);
+                   n->max_queues, (virtio_get_queue_max(vdev) - 1) / 2);
         virtio_cleanup(vdev);
         return;
     }
diff --git a/hw/s390x/s390-virtio-bus.c b/hw/s390x/s390-virtio-bus.c
index 047c963..2b41e32 100644
--- a/hw/s390x/s390-virtio-bus.c
+++ b/hw/s390x/s390-virtio-bus.c
@@ -715,6 +715,7 @@ static void virtio_s390_bus_class_init(ObjectClass *klass, void *data)
     bus_class->max_dev = 1;
     k->notify = virtio_s390_notify;
     k->get_features = virtio_s390_get_features;
+    k->queue_max = VIRTIO_PCI_QUEUE_MAX;
 }
 
 static const TypeInfo virtio_s390_bus_info = {
diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
index 0434f56..590eed5 100644
--- a/hw/s390x/virtio-ccw.c
+++ b/hw/s390x/virtio-ccw.c
@@ -1715,6 +1715,7 @@ static void virtio_ccw_bus_class_init(ObjectClass *klass, void *data)
     k->load_queue = virtio_ccw_load_queue;
     k->save_config = virtio_ccw_save_config;
     k->load_config = virtio_ccw_load_config;
+    k->queue_max = VIRTIO_PCI_QUEUE_MAX;
 }
 
 static const TypeInfo virtio_ccw_bus_info = {
diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
index c9bea06..fbdde2b 100644
--- a/hw/scsi/virtio-scsi.c
+++ b/hw/scsi/virtio-scsi.c
@@ -826,10 +826,10 @@ void virtio_scsi_common_realize(DeviceState *dev, Error **errp,
                 sizeof(VirtIOSCSIConfig));
 
     if (s->conf.num_queues == 0 ||
-            s->conf.num_queues > VIRTIO_PCI_QUEUE_MAX - 2) {
+            s->conf.num_queues > virtio_get_queue_max(vdev) - 2) {
         error_setg(errp, "Invalid number of queues (= %" PRIu32 "), "
                          "must be a positive integer less than %d.",
-                   s->conf.num_queues, VIRTIO_PCI_QUEUE_MAX - 2);
+                   s->conf.num_queues, virtio_get_queue_max(vdev) - 2);
         virtio_cleanup(vdev);
         return;
     }
diff --git a/hw/virtio/virtio-mmio.c b/hw/virtio/virtio-mmio.c
index 10123f3..2ae6942 100644
--- a/hw/virtio/virtio-mmio.c
+++ b/hw/virtio/virtio-mmio.c
@@ -403,6 +403,7 @@ static void virtio_mmio_bus_class_init(ObjectClass *klass, void *data)
     k->device_plugged = virtio_mmio_device_plugged;
     k->has_variable_vring_alignment = true;
     bus_class->max_dev = 1;
+    k->queue_max = VIRTIO_PCI_QUEUE_MAX;
 }
 
 static const TypeInfo virtio_mmio_bus_info = {
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index c7c3f72..075b13b 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -1498,6 +1498,7 @@ static void virtio_pci_bus_class_init(ObjectClass *klass, void *data)
     k->vmstate_change = virtio_pci_vmstate_change;
     k->device_plugged = virtio_pci_device_plugged;
     k->device_unplugged = virtio_pci_device_unplugged;
+    k->queue_max = VIRTIO_PCI_QUEUE_MAX;
 }
 
 static const TypeInfo virtio_pci_bus_info = {
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 17c1260..bbb224f 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -541,6 +541,14 @@ void virtio_update_irq(VirtIODevice *vdev)
     virtio_notify_vector(vdev, VIRTIO_NO_VECTOR);
 }
 
+int virtio_get_queue_max(VirtIODevice *vdev)
+{
+    BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
+    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
+
+    return k->queue_max;
+}
+
 void virtio_set_status(VirtIODevice *vdev, uint8_t val)
 {
     VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
@@ -599,7 +607,7 @@ void virtio_reset(void *opaque)
     vdev->config_vector = VIRTIO_NO_VECTOR;
     virtio_notify_vector(vdev, vdev->config_vector);
 
-    for(i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
+    for (i = 0; i < virtio_get_queue_max(vdev); i++) {
         vdev->vq[i].vring.desc = 0;
         vdev->vq[i].vring.avail = 0;
         vdev->vq[i].vring.used = 0;
@@ -738,7 +746,8 @@ int virtio_queue_get_num(VirtIODevice *vdev, int n)
 int virtio_queue_get_id(VirtQueue *vq)
 {
     VirtIODevice *vdev = vq->vdev;
-    assert(vq >= &vdev->vq[0] && vq < &vdev->vq[VIRTIO_PCI_QUEUE_MAX]);
+
+    assert(vq >= &vdev->vq[0] && vq < &vdev->vq[virtio_get_queue_max(vdev)]);
     return vq - &vdev->vq[0];
 }
 
@@ -774,28 +783,29 @@ void virtio_queue_notify(VirtIODevice *vdev, int n)
 
 uint16_t virtio_queue_vector(VirtIODevice *vdev, int n)
 {
-    return n < VIRTIO_PCI_QUEUE_MAX ? vdev->vq[n].vector :
+    return n < virtio_get_queue_max(vdev) ? vdev->vq[n].vector :
         VIRTIO_NO_VECTOR;
 }
 
 void virtio_queue_set_vector(VirtIODevice *vdev, int n, uint16_t vector)
 {
-    if (n < VIRTIO_PCI_QUEUE_MAX)
+    if (n < virtio_get_queue_max(vdev))
         vdev->vq[n].vector = vector;
 }
 
 VirtQueue *virtio_add_queue(VirtIODevice *vdev, int queue_size,
                             void (*handle_output)(VirtIODevice *, VirtQueue *))
 {
-    int i;
+    int i, queue_max = virtio_get_queue_max(vdev);
 
-    for (i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
+    for (i = 0; i < queue_max; i++) {
         if (vdev->vq[i].vring.num == 0)
             break;
     }
 
-    if (i == VIRTIO_PCI_QUEUE_MAX || queue_size > VIRTQUEUE_MAX_SIZE)
+    if (i == queue_max || queue_size > VIRTQUEUE_MAX_SIZE) {
         abort();
+    }
 
     vdev->vq[i].vring.num = queue_size;
     vdev->vq[i].vring.align = VIRTIO_PCI_VRING_ALIGN;
@@ -806,7 +816,7 @@ VirtQueue *virtio_add_queue(VirtIODevice *vdev, int queue_size,
 
 void virtio_del_queue(VirtIODevice *vdev, int n)
 {
-    if (n < 0 || n >= VIRTIO_PCI_QUEUE_MAX) {
+    if (n < 0 || n >= virtio_get_queue_max(vdev)) {
         abort();
     }
 
@@ -916,14 +926,14 @@ void virtio_save(VirtIODevice *vdev, QEMUFile *f)
     qemu_put_be32(f, vdev->config_len);
     qemu_put_buffer(f, vdev->config, vdev->config_len);
 
-    for (i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
+    for (i = 0; i < k->queue_max; i++) {
         if (vdev->vq[i].vring.num == 0)
             break;
     }
 
     qemu_put_be32(f, i);
 
-    for (i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
+    for (i = 0; i < k->queue_max; i++) {
         if (vdev->vq[i].vring.num == 0)
             break;
 
@@ -988,7 +998,7 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id)
     qemu_get_8s(f, &vdev->status);
     qemu_get_8s(f, &vdev->isr);
     qemu_get_be16s(f, &vdev->queue_sel);
-    if (vdev->queue_sel >= VIRTIO_PCI_QUEUE_MAX) {
+    if (vdev->queue_sel >= k->queue_max) {
         return -1;
     }
     qemu_get_be32s(f, &features);
@@ -1015,7 +1025,7 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id)
 
     num = qemu_get_be32(f);
 
-    if (num > VIRTIO_PCI_QUEUE_MAX) {
+    if (num > k->queue_max) {
         error_report("Invalid number of PCI queues: 0x%x", num);
         return -1;
     }
@@ -1125,15 +1135,15 @@ void virtio_instance_init_common(Object *proxy_obj, void *data,
 void virtio_init(VirtIODevice *vdev, const char *name,
                  uint16_t device_id, size_t config_size)
 {
-    int i;
+    int i, queue_max = virtio_get_queue_max(vdev);
     vdev->device_id = device_id;
     vdev->status = 0;
     vdev->isr = 0;
     vdev->queue_sel = 0;
     vdev->config_vector = VIRTIO_NO_VECTOR;
-    vdev->vq = g_malloc0(sizeof(VirtQueue) * VIRTIO_PCI_QUEUE_MAX);
+    vdev->vq = g_malloc0(sizeof(VirtQueue) * queue_max);
     vdev->vm_running = runstate_is_running();
-    for (i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
+    for (i = 0; i < queue_max; i++) {
         vdev->vq[i].vector = VIRTIO_NO_VECTOR;
         vdev->vq[i].vdev = vdev;
         vdev->vq[i].queue_index = i;
diff --git a/include/hw/virtio/virtio-bus.h b/include/hw/virtio/virtio-bus.h
index 0d2e7b4..4da8022 100644
--- a/include/hw/virtio/virtio-bus.h
+++ b/include/hw/virtio/virtio-bus.h
@@ -68,6 +68,7 @@ typedef struct VirtioBusClass {
      * Note that changing this will break migration for this transport.
      */
     bool has_variable_vring_alignment;
+    uint16_t queue_max;
 } VirtioBusClass;
 
 struct VirtioBusState {
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index d95f8b6..91fd673 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -179,6 +179,7 @@ void virtio_queue_notify(VirtIODevice *vdev, int n);
 uint16_t virtio_queue_vector(VirtIODevice *vdev, int n);
 void virtio_queue_set_vector(VirtIODevice *vdev, int n, uint16_t vector);
 void virtio_set_status(VirtIODevice *vdev, uint8_t val);
+int virtio_get_queue_max(VirtIODevice *vdev);
 void virtio_reset(void *opaque);
 void virtio_update_irq(VirtIODevice *vdev);
 int virtio_set_features(VirtIODevice *vdev, uint32_t val);
-- 
2.1.0