On Wed, Apr 23, 2025 at 12:58:19PM +0530, Vasant Hegde wrote:
On 4/11/2025 12:07 PM, Nicolin Chen wrote:
The vIOMMU object is designed to represent a slice of an IOMMU HW for its virtualization features shared with or passed to user space (a VM mostly) in a way of HW acceleration. This extended the HWPT-based design for more advanced virtualization feature.
A vCMDQ introduced by this series as a part of the vIOMMU infrastructure represents a HW supported queue/buffer for VM to use exclusively, e.g.
- NVIDIA's virtual command queue
- AMD vIOMMU's command buffer
I assume we can pass multiple buffer details (like GPA, size) from guest to hypervisor. Is that correct understanding?
Yes. The NVIDIA model passes through a Virtual-Interface to a VM, and the VM can allocate and map multiple command queues (buffers) to the V-Interface, by providing each command queue info in:
+struct iommu_vcmdq_tegra241_cmdqv { + __u32 vcmdq_id; + __u32 vcmdq_log2size; // size + __aligned_u64 vcmdq_base; // GPA };
Thanks Nicolin