From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH] kvm: qemu: Handle tap fds with IFF_VNET_HDR Date: Wed, 20 Aug 2008 20:51:57 +0300 Message-ID: <48AC59BD.9080407@qumranet.com> References: <1218485535-877-1-git-send-email-markmc@redhat.com> <48A1957C.4070007@qumranet.com> <1218638393.29159.38.camel@muff> <48A30ABE.3040903@qumranet.com> <1219251898.5068.33.camel@muff> <48AC5923.3040901@codemonkey.ws> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Mark McLoughlin , kvm@vger.kernel.org To: Anthony Liguori Return-path: Received: from il.qumranet.com ([212.179.150.194]:40172 "EHLO il.qumranet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752454AbYHTRv7 (ORCPT ); Wed, 20 Aug 2008 13:51:59 -0400 In-Reply-To: <48AC5923.3040901@codemonkey.ws> Sender: kvm-owner@vger.kernel.org List-ID: Anthony Liguori wrote: > Mark McLoughlin wrote: >> Allow users to pass an IFF_VNET_HDR tap fd via "-net tap,fd=X" >> by querying the fd with the recently added TUNGETIFF ioctl() to >> see if IFF_VNET_HDR has been enabled. >> >> Note: users wishing to pass an IFF_VNET_HDR tap fd to qemu >> should check both that a) this version of qemu can handle >> such an fd and b) that the TUNGETIFF ioctl() is available in >> the running kernel. >> >> We add a comment to the "qemu -help" output to indicate to >> users that this version of qemu supports IFF_VNET_HDR. >> > > The -help output is not a supported interface. An info command in the > monitor would be a better way to detect this. > You need to know this before you create a virtual machine. I suggested a 'qemu -capabilities' thing to describe what this qemu can do. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic.