IFF_VNET_HDR is a tun/tap flag that allows you to send and receive
large (i.e. GSO) packets and packets with partial checksums. Setting
the flag means that every packet is proceeded by the same header which
virtio uses to communicate GSO/csum metadata.
By enabling this flag on the tap fds we create, we greatly increase
the achievable throughput with virtio_net.
However, we need to be careful to only set the flag when a) QEMU has
support for this ABI and b) the value of the flag is queryable using
the TUNGETIFF ioctl.
It's nearly five months since kvm-74 - the first KVM release with this
feature - was released. Up until now, we've not added libvirt support
because there is no clean way to detect support for this in QEMU at
runtime. A brief attempt to add a "info capabilities" monitor command
to QEMU floundered. Perfect is the enemy of good enough. Probing the
KVM version will suffice for now.
Signed-off-by: Mark McLoughlin <markmc@redhat.com>
* src/virterror.c (virStrerror): New function.
(virReportSystemErrorFull): Don't leak "combined".
In fact, don't even attempt allocation.
Do include the result of formatted print in final diagnostic.
* src/proxy_internal.c (xenProxyCommand): Mark a diagnostic.
* src/xen_unified.c (xenUnifiedOpen, xenUnifiedAddDomainInfo):
Fix unmarked diagnostics by removing the diagnostic altogether:
replace each xenUnifiedError(...,VIR_ERR_NO_MEMORY call with a
call to virReportOOMError.
* .cvsignore: Don't ignore *.orig or *.rej. They're not build products.
Don't ignore the entire m4 directory.
* Makefile.maint (sync-vcs-ignore-files): Correct quoting.
Use sed rather than a for loop.
Search only version-controled files (for reproducibility)
* gnulib/lib/netinet/.cvsignore: Append missing newline-at-EOF,
so that the use of sed doesn't mistakenly concatenate lines.
* gnulib/lib/sys/.cvsignore: Likewise.
* m4/.cvsignore: Ignore acinclude.m4 and aclocal.m4, not *.m4.
* .hgignore: Regenerate.
* all .gitignore files: Regenerate.
from the post-install script:
Installing : libvirt
ln: creating symbolic link `/etc/libvirt/qemu/networks/autostart/default.xml': File exists
See https://bugzilla.redhat.com/462011
* src/network_driver.c (networkEnableIpForwarding): This function
would always return 1 (success). Now it returns 0 upon write or
close failure, being careful to preserve any errno from a write failure.
Add comments.
Jim Meyering