OASIS Mailing List ArchivesView the OASIS mailing list archive below
or browse/search using MarkMail.

 


Help: OASIS Mailing Lists Help | MarkMail Help

virtio-dev message

[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]


Subject: Re: [virtio-dev] [PATCH v5 08/10] vhost-user: remove the extra PCI capabilities


On 17/7/20 12:48 Î.Î., Stefan Hajnoczi wrote:

On Mon, May 18, 2020 at 11:37:19PM +0300, Nikos Dragazis wrote:
-Additional resources are configured on the virtio PCI transport by the following \field{struct virtio_pci_cap.cfg_type} values:
+\subsubsection{Doorbell layout}\label{sec:Device Types / Vhost-user Device Backend / Additional Device Resources / Doorbell layout}
-\begin{lstlisting}
-#define VIRTIO_PCI_CAP_DOORBELL_CFG 6
-#define VIRTIO_PCI_CAP_NOTIFICATION_CFG 7
-#define VIRTIO_PCI_CAP_SHARED_MEMORY_CFG 8
-\end{lstlisting}
+The device MUST reserve 2N+1 virtqueue indices that can be used by the driver to
+send doorbell notifications. The driver can use these indices to send doorbell
+notifications in the same way that it sends available buffer notifications
+\ref{sec:Basic Facilities of a Virtio Device / Notifications} for a virtqueue.
Notifications and doorbells should be first-class VIRTIO device model
concepts, like Shared Memory resources. It should not be necessary to
reserve dummy virtqueues (a hack for getting MSI-X vectors and doorbell
registers).

Well, it's not exactly equivalent to the shared memory resource
because, in case of doorbells and notifications, the functionality is
already there. But I see your point. It is a design issue. We could
definitely standardize the doorbell and notification resources, but I
don't see why this solution is preferable. Do you have something in
mind?


[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]