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| -rw-r--r-- | introduction.tex | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/introduction.tex b/introduction.tex index ba57419..146042d 100644 --- a/introduction.tex +++ b/introduction.tex @@ -2,22 +2,22 @@ \input{abstract.tex} - Straightforward: Virtio devices use normal bus mechanisms of +\begin{description} +\item[Straightforward:] Virtio devices use normal bus mechanisms of interrupts and DMA which should be familiar to any device driver author. There is no exotic page-flipping or COW mechanism: it's just - a normal device. -\footnote{This lack of page-sharing implies that the implementation of the + a normal device.\footnote{This lack of page-sharing implies that the implementation of the device (e.g. the hypervisor or host) needs full access to the guest memory. Communication with untrusted parties (i.e. inter-guest communication) requires copying. } - Efficient: Virtio devices consist of rings of descriptors +\item[Efficient:] Virtio devices consist of rings of descriptors for both input and output, which are neatly laid out to avoid cache effects from both driver and device writing to the same cache lines. - Standard: Virtio makes no assumptions about the environment in which +\item[Standard:] Virtio makes no assumptions about the environment in which it operates, beyond supporting the bus to which device is attached. In this specification, virtio devices are implemented over MMIO, Channel I/O and PCI bus transports @@ -27,11 +27,12 @@ between different transports. }, earlier drafts have been implemented on other buses not included here. - Extensible: Virtio devices contain feature bits which are +\item[Extensible:] Virtio devices contain feature bits which are acknowledged by the guest operating system during device setup. This allows forwards and backwards compatibility: the device offers all the features it knows about, and the driver acknowledges those it understands and wishes to use. +\end{description} \section{Terminology}\label{Terminology} |