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From: | Paolo Bonzini |
Subject: | Re: [RFC] adding a generic QAPI event for failed device hotunplug |
Date: | Mon, 22 Mar 2021 13:06:53 +0100 |
User-agent: | Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 |
On 22/03/21 07:39, David Gibson wrote:
QEMU doesn't really keep track of "in flight" unplug requests, and as long as that's the case, its timeout even will have the same issue.Not generically, maybe. In the PAPR code we effectively do, by means of the 'unplug_requested' boolean in the DRC structure. Maybe that's a mistake, but at the time I couldn't see how else to handle things.
No, that's good. x86 also tracks it in some registers that are accessible from the ACPI firmware. See "PCI slot removal notification" in docs/specs/acpi_pci_hotplug.txt.
Currently we will resolve all "in flight" requests at machine reset time, effectively completing those requests. Does that differ from x86 behaviour?
IIRC on x86 the requests are instead cancelled, but I'm not 100% sure. Paolo
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