tree 105b2cb2be076480a5a9c024990451cc2bb9182d
parent 523184972b282cd9ca17a76f6ca4742394856818
author Alex Williamson <alex.williamson@redhat.com> 1506969550 -0600
committer Alex Williamson <alex.williamson@redhat.com> 1506969550 -0600

vfio/pci: Virtualize Maximum Read Request Size

MRRS defines the maximum read request size a device is allowed to
make.  Drivers will often increase this to allow more data transfer
with a single request.  Completions to this request are bound by the
MPS setting for the bus.  Aside from device quirks (none known), it
doesn't seem to make sense to set an MRRS value less than MPS, yet
this is a likely scenario given that user drivers do not have a
system-wide view of the PCI topology.  Virtualize MRRS such that the
user can set MRRS >= MPS, but use MPS as the floor value that we'll
write to hardware.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>