Re: [PATCHv2 RFC] virtio-spec: flexible configuration layout

On Wed, Nov 09, 2011 at 10:24:47PM +0200, Sasha Levin wrote:

On Wed, 2011-11-09 at 21:59 +0200, Michael S. Tsirkin wrote:

[snip]

quoted

+\begin_layout Enumerate
+Reset the device.
+ This is not required on initial start up.
+\end_layout
+
+\begin_layout Enumerate
+The ACKNOWLEDGE status bit is set: we have noticed the device.
+\end_layout
+
+\begin_layout Enumerate
+The DRIVER status bit is set: we know how to drive the device.
+\end_layout
+
+\begin_layout Enumerate
+
+\change_inserted 1986246365 1320838089
+PCI capability list scan, detecting virtio configuration layout using Virtio
+ Structure PCI capabilities.

Does the legacy space always gets mapped from BAR0?

If yes,

Yes and this is repeated in several places. Not clear? How can this
be made clearer?

It'll be a bit harder deprecating it in the future.

Harder than ... what ?
IMO there's no way to put legacy anywhere except the first BAR
without breaking existing guests.

If not, this should actually be #1. Previous 3 bullets here were already
setting the status byte in the device config.

[snip]

quoted

+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Plain Layout
+
+\change_inserted 1986246365 1320786225
+28 bytes

This is the new virtio header min size, shouldn't it be 32? (20 + 4
(msi-x) + 4 (guest feature) + 4 (device features)).

Good catch, I'll correct this.

-- 

Sasha.