6886867e98
Devices that use address_space_rw to write large areas to memory (as opposed to address_space_map/unmap) were broken with respect to migration since fe680d0 (exec: Limit translation limiting in address_space_translate to xen, 2014-05-07). Such devices include IDE CD-ROMs. The reason is that invalidate_and_set_dirty (called by address_space_rw but not address_space_map/unmap) was only setting the dirty bit for the first page in the translation. To fix this, introduce cpu_physical_memory_set_dirty_range_nocode that is the same as cpu_physical_memory_set_dirty_range except it does not muck with the DIRTY_MEMORY_CODE bitmap. This function can be used if the caller invalidates translations with tb_invalidate_phys_page_range. There is another difference between cpu_physical_memory_set_dirty_range and cpu_physical_memory_set_dirty_flag; the former includes a call to xen_modified_memory. This is handled separately in invalidate_and_set_dirty, and is not needed in other callers of cpu_physical_memory_set_dirty_range_nocode, so leave it alone. Just one nit: now that invalidate_and_set_dirty takes care of handling multiple pages, there is no need for address_space_unmap to wrap it in a loop. In fact that loop would now be O(n^2). Reported-by: Dave Gilbert <dgilbert@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Tested-by: Gerd Hoffmann <kraxel@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Read the documentation in qemu-doc.html or on http://wiki.qemu-project.org - QEMU team