Re: [PATCH v3 2/3] uio_pci_generic: add MSI/MSI-X support

From: Avi Kivity
Date: Tue Oct 06 2015 - 11:27:54 EST




On 10/06/2015 05:46 PM, Michael S. Tsirkin wrote:
On Mon, Oct 05, 2015 at 11:28:03AM +0300, Avi Kivity wrote:
Eventfd is a natural enough representation of an interrupt; both kvm and
vfio use it, and are also able to share the eventfd, allowing a vfio
interrupt to generate a kvm interrupt, without userspace intervention, and
one day without even kernel intervention.
eventfd without kernel intervention sounds unlikely.

kvm might configure the cpu such that an interrupt will not trigger a
vmexit. eventfd seems like an unlikely interface to do that: with the
eventfd, device triggering it has no info about the interrupt so it
can't send it to the correct VM.

https://lwn.net/Articles/650863/
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