The MemoryRegionSection contains enough information to access the
RAM region underlying the framebuffer, and can be cached inside the
display device.
By doing this, the new framebuffer_update_memory_section function can
enable dirty memory logging on the relevant RAM region. The function
must be called whenever the stride or base of the framebuffer changes;
a simple way to cover these cases is to call it on every full frame
invalidation, which is a rare case.
framebuffer_update_display now works entirely on a MemoryRegionSection,
without going through cpu_physical_memory_map/unmap.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
