On 11/9/21 09:42, Andrew Jones wrote:
On Tue, Nov 09, 2021 at 08:10:34AM +0100, Thomas Huth wrote:
On 08/11/2021 14.00, Pierre Morel wrote:
On 11/3/21 09:14, Thomas Huth wrote:
On 03/11/2021 08.56, Andrew Jones wrote:
On Fri, Aug 27, 2021 at 12:17:19PM +0200, Pierre Morel wrote:
+
+#define VIRTIO_ID_PONG 30 /* virtio pong */
I take it this is a virtio test device that ping-pong's I/O. It sounds
useful for other VIRTIO transports too. Can it be ported? Hmm, I can't
find it in QEMU at all?
I also wonder whether we could do testing with an existing device
instead? E.g. do a loopback with a virtio-serial device? Or use two
virtio-net devices, connect them to a QEMU hub and send a packet
from one device to the other? ... that would be a little bit more
complicated here, but would not require a PONG device upstream
first, so it could also be used for testing older versions of
QEMU...
Thomas
Yes having a dedicated device has the drawback that we need it in QEMU.
On the other hand using a specific device, serial or network, wouldn't
we get trapped with a reduce set of test possibilities?
The idea was to have a dedicated test device, which could be flexible
and extended to test all VIRTIO features, even the current
implementation is yet far from it.
Do you have anything in the works that could only be tested with a dedicated
test device? If not, I'd rather go with the loopback via virtio-net, I think
(you can peek into the s390-ccw bios sources to see how to send packets via
virtio-net, shouldn't be too hard to do, I think).
The pong device could later be added on top for additional tests that are
not possible with virtio-net. And having some basic tests with virito-net
has also the advantage that the k-u-t work with QEMU binaries where the pong
device is not available, e.g. older versions and downstream versions that
only enable the bare minimum of devices to keep the attack surface small.
I'd also like to see the testdev we already have, qemu:chardev/testdev.c,
get more functions, but I'm not sure virtio-serial will allow you to
exercise all the virtio functionality that you'd like to.
Thanks,
drew
Yes, that is why I did not used it first.
But OK, I understand what you both want and will build something in that
direction, virtio-net, virtio-serial and come back later to something
independent of existing devices if we find it does have a purpose.
Thanks for the comments.
Regards,
Pierre
--
Pierre Morel
IBM Lab Boeblingen
