[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] [RFC] ARM PCI Passthrough design document

On 29/06/17 16:17, Vikram Sethi wrote:
Hi Julien,

Hi Vikram,

My thoughts are that while it is not essential to recover from AER and DPC 
initially, it is critical to at least take the slot offline and notify drivers 
so they quiesce.
Without this basic handling, it is possible to create backups in some hardware 
that result in CPU hangs for loads to adapter MMIO/cfg space and we don't want 
i.e it is probably OK to lose the slot/adapter in initial implementation, but 
IMO it is NOT ok to crash/reboot the system by having watchdog kick in.
We do need to minimally describe what we will do with the AER and DPC interrupts: are 
they first handled by Xen and sent as "emulated" interrupt to owning domain?
Or are the interrupts ignored in initial implementation (not a good idea IMO)?

I don't think it is possible to ask everything to be supported in the initial implementation. We have to draw a line so we can get a tech preview support in Xen as soon as possible.

At the moment, I am focusing on the foundation that will be required for all the boards. I have put them in my low priority tasks because AER, DPC, hotplug are optional features and hence not available everywhere.

Feel free to send me a proposal for the design document, patch series if you want them to be included in the initial implementation.

Hotplug also does not need to be solved right away. But we need to at least 
walk through the flows and convince ourselves we are not painting ourselves in 
a corner.
I will be in Budapest for Xen developer summit and we can walk through the ACPI 
hotplug flow and see how that *could* fit into proposed Xen design.

Glad to know that. Let's schedule some discussions during the summit.


Julien Grall

Xen-devel mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.