Re: [Qemu-devel] [PATCH V7 08/16] virtio: introduce bus specific queue limit

[Jason Wang <jasowang@redhat.com>]

On Mon, Apr 27, 2015 at 7:05 PM, Michael S. Tsirkin <mst@redhat.com> 
wrote:
> On Thu, Apr 23, 2015 at 02:21:41PM +0800, Jason Wang wrote:
>>  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>
>>  Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
> 
> Is this still needed if you drop the attempt to
> keep the limit around for old machine types?

If we agree to drop, we probably need transport specific macro.

> 
> 
>>  ---
>>   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
>