Re: [PATCH v9 7/7] vhost-user-device: Add shared memory BAR

[Stefan Hajnoczi <stefanha@redhat.com>]

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On Wed, Oct 15, 2025 at 10:59:30AM +0200, Albert Esteve wrote:
> @@ -25,10 +29,37 @@ OBJECT_DECLARE_SIMPLE_TYPE(VHostUserDevicePCI, VHOST_USER_TEST_DEVICE_PCI)
>  static void vhost_user_device_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
>  {
>      VHostUserDevicePCI *dev = VHOST_USER_TEST_DEVICE_PCI(vpci_dev);
> -    DeviceState *vdev = DEVICE(&dev->vub);
> +    DeviceState *dev_state = DEVICE(&dev->vub);
> +    VirtIODevice *vdev = VIRTIO_DEVICE(dev_state);
> +    VirtioSharedMemory *shmem, *next;
> +    uint64_t offset = 0, shmem_size = 0;
>  
> +    vpci_dev->modern_mem_bar_idx = 2;
>      vpci_dev->nvectors = 1;
> -    qdev_realize(vdev, BUS(&vpci_dev->bus), errp);
> +    qdev_realize(dev_state, BUS(&vpci_dev->bus), errp);
> +
> +    QSIMPLEQ_FOREACH_SAFE(shmem, &vdev->shmem_list, entry, next) {
> +        if (shmem->mr.size > UINT64_MAX - shmem_size) {
> +            error_setg(errp, "Total shared memory required overflow");
> +            return;
> +        }
> +        shmem_size = shmem_size + shmem->mr.size;
> +    }
> +    if (shmem_size) {

Let's reject invalid BAR configurations when VIRTIO Shared Memory
Regions are in use:

  if (vpci_dev->flags & VIRTIO_PCI_FLAG_MODERN_PIO_NOTIFY) {
      error_setg(errp, "modern-pio-notify is not supported due to PCI BAR layout limitations");
      return;
  }

Otherwise:

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

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