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Re: [Qemu-devel] [PATCHv3 1/2] pci: move check for existing devfn into n
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From: |
Mark Cave-Ayland |
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Subject: |
Re: [Qemu-devel] [PATCHv3 1/2] pci: move check for existing devfn into new pci_bus_devfn_available() helper |
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Date: |
Wed, 6 Sep 2017 20:02:30 +0100 |
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User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 |
On 04/09/17 11:01, Yi Min Zhao wrote:
> I want to ask a question. According to the next patch, you check
> bus->devices[devfn]
> and reserved bit separately. Why not move the reserved bit check here?
> I think bus->devices[devfn] != NULL or revsered bit set means slot is
> unavailable.
Primarily it was to allow callers to distinguish between the two
different cases i.e. the error message can tell you that the reason the
slot was unavailable was because it was reserved, i.e. you can *never*
plug anything into it compared with unavailable where someone has
plugged something into the slot with -device but it could be later
removed, for example with hotplug.
ATB,
Mark.