On Tue, Oct 01, 2024 at 10:48:15AM -0300, Jason Gunthorpe wrote:
On Sun, Sep 29, 2024 at 03:19:42PM +0800, Yi Liu wrote:
So their viommu HW concepts come along with a requirement that there be a fixed translation for the VM, which we model by attaching a S2 HWPT to the VIOMMU object which get's linked into the IOMMU HW as the translation for the queue memory.
Is the mapping of the S2 be static? or it an be unmapped per userspace?
In principle it should be dynamic, but I think the vCMDQ stuff will struggle to do that
Yea. vCMDQ HW requires a setting of the physical address of the base address to a queue in the VM's ram space. If the S2 mapping changes (resulting a different queue location in the physical memory), VMM should notify the kernel for a HW reconfiguration.
I wonder what all the user cases are, which can cause a shifting of S2 mappings? VM migration? Any others?
Thanks Nicolin