On Wed, Jun 02, 2010 at 12:49:28PM +0300, Avi Kivity wrote:
On 06/02/2010 12:45 PM, Joerg Roedel wrote:Ah ok, so its only about the database which keeps the mapping
IOMMU mapped memory can not be swapped out because we can't do demandvhost doesn't pin memory.
paging on io-page-faults with current devices. We have to pin _all_
userspace memory that is mapped into an IOMMU domain.
What I proposed is to describe the memory map using an object (fd), and
pass it around to clients that use it: kvm, vhost, vfio. That way you
maintain the memory map in a central location and broadcast changes to
clients. Only a vfio client would result in memory being pinned.
information.
It can still work, but the interface needs to be extended to includeThats hard to do. I am not sure about VT-d but the AMD IOMMU has no
dirty bitmap logging.
dirty-bits in the page-table. And without demand-paging we can't really
tell what pages a device has written to. The only choice is to mark all
IOMMU-mapped pages dirty as long as they are mapped.