Commit Graph

2 Commits

Author SHA1 Message Date
Daniel P. Berrangé
0279a51b83 tests: fix name of 32-bit x86 QEMU binary
The 32-bit x86 binary is called qemu-system-i386, not
qemu-system-i686. This mistake across many test XML files was
not noticed because the mistake was also made in testutilsqemu.c
when mocking the capabilities.

Reviewed-by: Erik Skultety <eskultet@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-12-03 13:57:44 +00:00
Laine Stump
7cd0911e1a qemu: support unmanaged target tap dev for <interface type='ethernet'>
If managed='no', then the tap device must already exist, and setting
of MAC address and online status (IFF_UP) is skipped.

NB: we still set IFF_VNET_HDR and IFF_MULTI_QUEUE as appropriate,
because those bits must be properly set in the TUNSETIFF we use to set
the tap device name of the handle we've opened - if IFF_VNET_HDR has
not been set and we set it the request will be honored even when
running libvirtd unprivileged; if IFF_MULTI_QUEUE is requested to be
different than how it was created, that will result in an error from
the kernel. This means that you don't need to pay attention to
IFF_VNET_HDR when creating the tap devices, but you *do* need to set
IFF_MULTI_QUEUE if you're going to use multiple queues for your tap
device.

NB2: /dev/vhost-net normally has permissions 600, so it can't be
opened by an unprivileged process. This would normally cause a warning
message when using a virtio net device from an unprivileged
libvirtd. I've found that setting the permissions for /dev/vhost-net
permits unprivileged libvirtd to use vhost-net for virtio devices, but
have no idea what sort of security implications that has. I haven't
changed libvrit's code to avoid *attempting* to open /dev/vhost-net -
if you are concerned about the security of opening up permissions of
/dev/vhost-net (probably a good idea at least until we ask someone who
knows about the code) then add <driver name='qemu'/> to the interface
definition and you'll avoid the warning message.

Note that virNetDevTapCreate() is the correct function to call in the
case of an existing device, because the same ioctl() that creates a
new tap device will also open an existing tap device.

Resolves: https://bugzilla.redhat.com/1723367 (partially)

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2019-09-09 14:38:01 -04:00