Add a print explaining why vhost_vdpa_alloc_domain failed if the device is not IOMMU cache coherent capable. Without this print, we have no hint why the operation failed. For example: $ virsh start <domain> error: Failed to start domain <domain> error: Unable to open '/dev/vhost-vdpa-<idx>' for vdpa device: Unknown error 524 Suggested-by: Eugenio Perez Martin <eperezma@xxxxxxxxxx> Signed-off-by: Alvaro Karsz <alvaro.karsz@xxxxxxxxxxxxx> --- drivers/vhost/vdpa.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c index 23db92388393..56287506aa0d 100644 --- a/drivers/vhost/vdpa.c +++ b/drivers/vhost/vdpa.c @@ -1151,8 +1151,11 @@ static int vhost_vdpa_alloc_domain(struct vhost_vdpa *v) if (!bus) return -EFAULT; - if (!device_iommu_capable(dma_dev, IOMMU_CAP_CACHE_COHERENCY)) + if (!device_iommu_capable(dma_dev, IOMMU_CAP_CACHE_COHERENCY)) { + dev_err(&v->dev, + "Failed to allocate domain, device is not IOMMU cache coherent capable\n"); return -ENOTSUPP; + } v->domain = iommu_domain_alloc(bus); if (!v->domain) -- 2.34.1