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

From	"Michael S. Tsirkin" <mst@redhat.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v3 2/3] uio_pci_generic: add MSI/MSI-X support
Date	2015-10-06 16:50 +0200
Message-ID	<qgBJ1-Em-49@gated-at.bofh.it> (permalink)
References	<qfYoi-2RY-5@gated-at.bofh.it> <qfYoi-2RY-11@gated-at.bofh.it> <qg4tH-3lu-1@gated-at.bofh.it> <qg9jJ-1RW-37@gated-at.bofh.it>
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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.

-- 
MST
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Re: [PATCH v3 2/3] uio_pci_generic: add MSI/MSI-X support "Michael S. Tsirkin" <mst@redhat.com> - 2015-10-06 16:50 +0200
  Re: [PATCH v3 2/3] uio_pci_generic: add MSI/MSI-X support Avi Kivity <avi@scylladb.com> - 2015-10-06 17:30 +0200

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