On Thu, Nov 21, 2019 at 09:57:38AM -0700, Alex Williamson wrote: > On Thu, 21 Nov 2019 11:56:02 +1100 > David Gibson <david@xxxxxxxxxxxxxxxxxxxxx> wrote: > > > Due to the way feature negotiation works in PAPR (which is a > > paravirtualized platform), we can end up changing the global irq chip > > at runtime, including it's KVM accelerate model. That causes > > complications for VFIO devices with INTx, which wire themselves up > > directly to the KVM irqchip for performance. > > > > This series introduces a new notifier to let VFIO devices (and > > anything else that needs to in the future) know about changes to the > > master irqchip. It modifies VFIO to respond to the notifier, > > reconnecting itself to the new KVM irqchip as necessary. > > > > In particular this removes a misleading (though not wholly inaccurate) > > warning that occurs when using VFIO devices on a pseries machine type > > guest. > > > > Open question: should this go into qemu-4.2 or wait until 5.0? It's > > has medium complexity / intrusiveness, but it *is* a bugfix that I > > can't see a simpler way to fix. It's effectively a regression from > > qemu-4.0 to qemu-4.1 (because that introduced XIVE support by > > default), although not from 4.1 to 4.2. > > Looks reasonable to me for 4.2, the vfio changes are not as big as they > appear. If Paolo approves this week, I can send a pull request, > otherwise I can leave my ack for someone else as I'll be on PTO/holiday > next week. Thanks, I'm happy to take it through my tree, and expect to be sending a PR in that timescale, so an ack sounds good. I've pulled the series into my ppc-for-4.2 branch tentatively. -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson
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