On Wed, Sep 09, 2026 at 16:29:47 +0800, Zhenzhong Duan wrote:
Hi,
This series adds support for configuring Intel vIOMMU (VT-d) in domain XML and formatting them onto the QEMU command line:
I've got couple of high-level questions:
* scalable_mode: Configures scalable mode support ('on'/'off'). * fsts: Enables First-Stage Translation support ('on'/'off'). * pasid_bits: Sets the number of supported PASID bits. * svm: Enables Shared Virtual Memory (SVM) / PRQ support ('on'/'off').
Are users actually expected to set these? The libvirt documentation that is added by this series doesn't really describe what the feature does, just names them. So ...
With these attributes, users can configure advanced vIOMMU features for both emulated devices and assigned host devices (e.g., vSVA / nested translation via iommufd and first-stage translation).
... can users meaningfully influence what they get? Arent't the defaults enough? I'll also add some style/code comments inline.