[virtio] Replace virtio-net with native iPXE driver
This patch adds a native iPXE virtio-net driver and removes the legacy
Etherboot virtio-net driver. The main reasons for doing this are:
1. Multiple virtio-net NICs are now supported by iPXE. The legacy
driver kept global state and caused issues in virtual machines with
more than one virtio-net device.
2. Faster downloads. The native iPXE driver downloads 100 MB over
HTTP in 12s, the legacy Etherboot driver in 37s. This simple
benchmark uses KVM with tap networking and the Python
SimpleHTTPServer both running on the same host.
Changes to core virtio code reduce vring descriptors to 256 (QEMU uses
128 for virtio-blk and 256 for virtio-net) and change the opaque token
from u16 to void*. Lowering the descriptor count reduces memory
consumption. The void* opaque token change makes driver code simpler.
Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Access to the gpxe.org and etherboot.org domains and associated
resources has been revoked by the registrant of the domain. Work
around this problem by renaming project from gPXE to iPXE, and
updating URLs to match.
Also update README, LOG and COPYRIGHTS to remove obsolete information.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The virtnet_transmit() logic for waiting the packet to be transmitted is
reversed: we can't wait the packet to be transmitted if we didn't kick()
the ring yet. The vring_more_used() while loop logic is reversed also,
that explains why the code works today.
The current code risks trying to free a buffer from the used ring
when none was available, that will happen most times because KVM
doesn't handle the packet immediately on kick(). Luckily it was working
because it was unlikely to have a buffer still queued for transmit when
virtnet_transmit() was called.
Also, adds a BUG_ON() to vring_get_buf(), to catch cases where we try
to free a buffer from the used ring when there was none available.
Patch for Etherboot. gPXE has the same problem on the code, but I hadn't
a chance to test gPXE using virtio-net yet.
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>
This patch adds support for the virtio-net adapter provided by KVM.
Written by Laurent Vivier <Laurent.Vivier@bull.net> for Etherboot.
Wrapped as legacy driver for gPXE by Stefan Hajnoczi
<stefanha@gmail.com>.
Stefan Weil