On Tue, Dec 17, 2024 at 09:00:19PM -0800, Nicolin Chen wrote: > +/* An iommufd_virq_header packs a vIOMMU interrupt in an iommufd_virq queue */ > +struct iommufd_virq_header { > + struct list_head node; > + ssize_t irq_len; > + void *irq_data; > +}; Based on how it is used in iommufd_viommu_report_irq() + header = kzalloc(sizeof(*header) + irq_len, GFP_KERNEL); + header->irq_data = (void *)header + sizeof(*header); + memcpy(header->irq_data, irq_ptr, irq_len); It should be a flex array and use the various flexarray tools struct iommufd_virq_header { ssize_t irq_len; u64 irq_data[] __counted_by(irq_len); } Jason