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Re: [RFC 0/3] try to solve the DMA to MMIO issue
From: |
Li Qiang |
Subject: |
Re: [RFC 0/3] try to solve the DMA to MMIO issue |
Date: |
Thu, 3 Sep 2020 19:11:18 +0800 |
Peter Maydell <peter.maydell@linaro.org> 于2020年9月3日周四 下午6:53写道:
>
> On Thu, 3 Sep 2020 at 04:55, Jason Wang <jasowang@redhat.com> wrote:
> > I think we still need to seek a way to address this issue completely.
> >
> > How about adding a flag in MemoryRegionOps and detect the reentrancy
> > through that flag?
>
> This won't catch everything. Consider this situation:
> Device A makes DMA access to device B
> Device B's write-handling causes it to raise an
> outbound qemu_irq signal
> The qemu_irq signal is connected to device A
Here mean device A is an interrupt controller?
This is special case I think.
> Now we have reentered into device A's code
>
> That is to say, the problem is general to "device A does
> something that affects device B" links of all kinds, which
As the P2P is a normal behavior, we can't just prevent this.
Thanks,
Li Qiang
> can form loops. Self-DMA is just an easy way to find one
> category of these with the fuzzer.
>
> thanks
> -- PMM
- Re: [RFC 3/3] virtio-gpu: make the IO handler reentrant, (continued)
Re: [RFC 0/3] try to solve the DMA to MMIO issue, Peter Maydell, 2020/09/03
- Re: [RFC 0/3] try to solve the DMA to MMIO issue,
Li Qiang <=
- Re: [RFC 0/3] try to solve the DMA to MMIO issue, Peter Maydell, 2020/09/03
- Re: [RFC 0/3] try to solve the DMA to MMIO issue, Li Qiang, 2020/09/03
- Re: [RFC 0/3] try to solve the DMA to MMIO issue, Peter Maydell, 2020/09/03
- Re: [RFC 0/3] try to solve the DMA to MMIO issue, Philippe Mathieu-Daudé, 2020/09/03
- Re: [RFC 0/3] try to solve the DMA to MMIO issue, Peter Maydell, 2020/09/03
Re: [RFC 0/3] try to solve the DMA to MMIO issue, Jason Wang, 2020/09/03