Messages in this thread | | | Date | Tue, 22 Dec 2009 14:15:38 -0500 | From | Gregory Haskins <> | Subject | Re: [GIT PULL] AlacrityVM guest drivers for 2.6.33 |
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On 12/22/09 1:53 PM, Avi Kivity wrote: > I asked why the irqfd/ioeventfd mechanisms are insufficient, and you did not reply. >
BTW: the ioeventfd issue just fell through the cracks, so sorry about that. Note that I have no specific issue with irqfd ever since the lockless IRQ injection code was added.
ioeventfd turned out to be suboptimal for me in the fast path for two reasons:
1) the underlying eventfd is called in atomic context. I had posted patches to Davide to address that limitation, but I believe he rejected them on the grounds that they are only relevant to KVM.
2) it cannot retain the data field passed in the PIO. I wanted to have one vector that could tell me what value was written, and this cannot be expressed in ioeventfd.
Based on this, it was a better decision to add a ioevent interface to xinterface. It neatly solves both problems.
Kind Regards, -Greg
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