On Sun, 24 May 2020 at 11:30, Philippe Mathieu-Daudé <phi...@redhat.com> wrote: > It looks to me a normal behavior for a DMA device. DMA devices have a > different address space view than the CPUs. > Also note the fw_cfg is a generic device, not restricted to the x86 arch.
In an ideal world all our DMA devices would use some kind of common framework or design pattern so they didn't hog all the CPU and/or spend minutes with the BQL held if the guest requests an enormous-sized DMA. In practice many of them just have a simple "loop until the DMA transfer is complete" implementation... thanks -- PMM
