Re: [RFC 0/4] Add a 'in_mmio' device flag to avoid the DMA to MMIO

[Peter Maydell]

On Sun, 20 Sep 2020 at 08:56, Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> On 08/09/20 18:41, Li Qiang wrote:
> > Currently the qemu device fuzzer find some DMA to MMIO issue. If the
> > device handling MMIO currently trigger a DMA which the address is MMIO,
> > this will reenter the device MMIO handler. As some of the device doesn't
> > consider this it will sometimes crash the qemu.

> I don't think this is a good solution.  These are device bugs and they
> need to be fixed.

Do you have an opinion on what the right approach to fixing them is?
It seems like a hard problem to me; my brain has been too full of
cotton wool recently and I haven't felt up to sitting down and
trying to think through whether there's a clean way to handle the
reentrancy-into-device-code problem in the general case...

thanks
-- PMM