Re: [PATCH v3 06/14] iommufd: Add IOMMUFD_OBJ_VIRQ and IOMMUFD_CMD_VIRQ_ALLOC

On Thu, Jan 02, 2025 at 04:52:46PM -0400, Jason Gunthorpe wrote:

On Tue, Dec 17, 2024 at 09:00:19PM -0800, Nicolin Chen wrote:

quoted

+/* 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);
}

Changed to
-------------------------------------------------------------------------
/* An iommufd_vevent represents a vIOMMU event in an iommufd_veventq */
struct iommufd_vevent {
	struct list_head node;
	ssize_t data_len;
	u64 event_data[] __counted_by(data_len);
};
[...]
	vevent = kmalloc(struct_size(vevent, event_data, data_len), GFP_KERNEL);
-	header->irq_data = (void *)header + sizeof(*header);
-------------------------------------------------------------------------

Thanks
Nicolin