Yes, I'm seeing the
(XEN) testing: enable log dirty mode
in xl dmesg.

Also, here are logs and additional information from a start with a xen
build up to the 077fc1c changeset. DomU Name is WORK.
I haven't attached a xl dmesg log because it was only filled with this:

domain = 0, device id = 0x98, fault address = 0xffffffc0, flags = 0
(XEN) AMD-Vi: IO_PAGE_FAULT: domain = 0, device id = 0x90, fault address =
0xffffffc0, flags = 0
(XEN) AMD-Vi: IO_PAGE_FAULT: domain = 0, device id = 0x98, fault address =
0xffffffc0, flags = 0
(XEN) AMD-Vi: IO_PAGE_FAULT: domain = 0, device id = 0x90, fault address =
0xffffffc0, flags = 0
(XEN) AMD-Vi: IO_PAGE_FAULT: domain = 0, device id = 0x98, fault address =
0xffffffc0, flags = 0
(XEN) AMD-Vi: IO_PAGE_FAULT: domain = 0, device id = 0x90, fault address =
0xffffffc0, flags = 0
(XEN) AMD-Vi: IO_PAGE_FAULT: domain = 0, device id = 0x98, fault address =
0xffffffc0, flags = 0
(XEN) AMD-Vi: IO_PAGE_FAULT: domain = 0, device id = 0x90, fault address =
0xffffffc0, flags = 0