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From: Rusty Russell <rusty@rustcorp.com.au>
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Date: Thu, 03 Nov 2011 11:26:23 +1030
Message-ID: <878vnyt45k.fsf@rustcorp.com.au>
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Subject: Re: [Qemu-devel] [PATCH RFC 0/2] virtio-pci: polling mode support
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To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Anthony Liguori <aliguori@us.ibm.com>, qemu-devel@nongnu.org, Jan Kiszka <jan.kiszka@siemens.com>, Alexander Graf <agraf@suse.de>, virtualization@lists.linux-foundation.org, Blue Swirl <blauwirbel@gmail.com>, Stefan Weil <weil@mail.berlios.de>, Avi Kivity <avi@redhat.com>, Richard Henderson <rth@twiddle.net>

On Wed, 2 Nov 2011 21:02:42 +0200, "Michael S. Tsirkin" <mst@redhat.com> wrote:
> MSIX spec requires that device can be operated with
> all vectors masked, by polling.
> 
> So the following patchset (lightly tested) adds this
> ability: when driver reads ISR, the device
> recalls a pending notification, and returns
> pending status in the ISR register.
> 
> The polling driver can operate as follows:
> - map all VQs and config to the same vector
> - poll ISR to get status - this also flushes VQ updates to memory
> - handle config change or VQ event depending on ISR
> 
> Comments?

This seems sane to me...

Cheers,
Rusty.