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[libvirt] [PATCH] fix minor typo
by John Levon 15 Aug '08

15 Aug '08

Fix a typo in the message for the 'dump' command in virsh. Signed-off-by: John Levon <john.levon(a)sun.com> Index: src/virsh.c =================================================================== RCS file: /data/cvs/libvirt/src/virsh.c,v retrieving revision 1.157 diff -u -r1.157 virsh.c --- src/virsh.c 22 Jul 2008 16:12:01 -0000 1.157 +++ src/virsh.c 13 Aug 2008 15:50:09 -0000 @@ -1320,7 +1320,7 @@ return FALSE; if (virDomainCoreDump(dom, to, 0) == 0) { - vshPrint(ctl, _("Domain %s dumpd to %s\n"), name, to); + vshPrint(ctl, _("Domain %s dumped to %s\n"), name, to); } else { vshError(ctl, FALSE, _("Failed to core dump domain %s to %s"), name, to);

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[libvirt] Reusing dumpxml output
by Stefan de Konink 15 Aug '08

15 Aug '08

I would like to reuse configurations that have been edited using the libvirt api. For example by attaching interfaces. Now the output that dumpxml generates, is very 'specific' to an active configuration. I am not able to use a stored configuration from an active domain to redefine it after it has been undefined. Is there a trick to do so? Or should one really strip all 'live' attributes first? Stefan

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[libvirt] breaking out of virsh console?
by Schroeder, Paul 14 Aug '08

14 Aug '08

Hello all... In my VM's inittab, I set agetty to run on ttyS0 so I could do "virsh console myvm" and log in from the host machine's command line. It works perfectly. Trouble is, I don't know how to break out of it to get back to the command line on my host. I've only been able to do so by killing the virsh process. There's gotta be a better way.. Right? Thanks...Paul...

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[libvirt] VMWare support, any news?
by Yushu Yao 14 Aug '08

14 Aug '08

Hi All, I noticed there are some discussion about VMWare support of libvirt several back in April-May. Just wondering is there a prototype yet? The function I¹m interested in is to stop/start a VM by VMWare player/workstation/free server. Thanks, -Yushu

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[libvirt] [PATCH] get memory in openvz driver
by Evgeniy Sokolov 14 Aug '08

14 Aug '08

OpenVZ has several parameters for memory management. All of them can be configured independetly. Patch allow to get configuration of memory from container config and then calculate total usage of memory. It is open question how to manage memory?

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[libvirt] [PATCH] kvm/virtio: Set IFF_VNET_HDR when setting up tap fds
by Mark McLoughlin 13 Aug '08

13 Aug '08

Hey, Here's a patch that allows libvirt created guests to use KVM's recent GSO support in order to increase the throughput achieved with virtio_net network interfaces. We shouldn't apply this yet - we need the kernel and kvm TUNGETIFF patches to be applied first - so this is just intended as an RFC. See also: http://marc.info/?l=linux-netdev&m=121863813904363 and: http://marc.info/?l=kvm&m=121863857305255 Cheers, Mark. Subject: [PATCH] kvm/virtio: Set IFF_VNET_HDR when setting up tap fds 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) KVM has support for this ABI and b) the value of the flag is queryable using the TUNGETIFF ioctl. Signed-off-by: Mark McLoughlin <markmc(a)redhat.com> Index: libvirt/src/bridge.c =================================================================== --- libvirt.orig/src/bridge.c 2008-08-13 15:40:34.000000000 +0100 +++ libvirt/src/bridge.c 2008-08-13 15:40:53.000000000 +0100 @@ -275,10 +275,52 @@ #endif /** + * brProbeVnetHdr: + * @tapfd: a tun/tap file descriptor + * + * Check whether it is safe to enable the IFF_VNET_HDR flag on the + * tap interface. + * + * Setting IFF_VNET_HDR enables KVM's virtio_net driver to allow + * guests to pass larger (GSO) packets, with partial checksums, to + * the host. This greatly increases the achievable throughput. + * + * It is only useful to enable this when we're setting up a virtio + * interface. And it is only *safe* to enable it when we know for + * sure that a) qemu has support for IFF_VNET_HDR and b) the running + * kernel implements the TUNGETIFF ioctl(), which qemu needs to query + * the supplied tapfd. + * + * Returns 0 in case of success or an errno code in case of failure. + */ +static int +brProbeVnetHdr(int tapfd) +{ +#if defined(IFF_VNET_HDR) && defined(TUNGETFEATURES) && defined(TUNGETIFF) + unsigned int features; + struct ifreq dummy; + + if (ioctl(tapfd, TUNGETFEATURES, &features) != 0) + return 0; + + if (!(features & IFF_VNET_HDR)) + return 0; + + if (ioctl(tapfd, TUNGETIFF, &dummy) != -1 || errno != EBADFD) + return 0; + + return 1; +#else + return 0; +#endif +} + +/** * brAddTap: * @ctl: bridge control pointer * @bridge: the bridge name * @ifname: the interface name (or name template) + * @vnet_hdr: whether to try enabling iFF_VNET_HDR * @tapfd: file descriptor return value for the new tap device * * This function creates a new tap device on a bridge. @ifname can be either @@ -292,6 +334,7 @@ brAddTap(brControl *ctl, const char *bridge, char **ifname, + int vnet_hdr, int *tapfd) { int id, subst, fd; @@ -307,6 +350,9 @@ if ((fd = open("/dev/net/tun", O_RDWR)) < 0) return errno; + if (vnet_hdr) + vnet_hdr = brProbeVnetHdr(fd); + do { struct ifreq try; int len; @@ -315,6 +361,11 @@ try.ifr_flags = IFF_TAP|IFF_NO_PI; +#ifdef IFF_VNET_HDR + if (vnet_hdr) + try.ifr_flags |= IFF_VNET_HDR; +#endif + if (subst) { len = snprintf(try.ifr_name, BR_IFNAME_MAXLEN, *ifname, id); if (len >= BR_IFNAME_MAXLEN) { Index: libvirt/src/bridge.h =================================================================== --- libvirt.orig/src/bridge.h 2008-08-13 15:40:34.000000000 +0100 +++ libvirt/src/bridge.h 2008-08-13 15:40:53.000000000 +0100 @@ -61,6 +61,7 @@ int brAddTap (brControl *ctl, const char *bridge, char **ifname, + int vnet_hdr, int *tapfd); int brSetInterfaceUp (brControl *ctl, Index: libvirt/src/qemu_conf.c =================================================================== --- libvirt.orig/src/qemu_conf.c 2008-08-13 15:40:34.000000000 +0100 +++ libvirt/src/qemu_conf.c 2008-08-13 15:41:15.000000000 +0100 @@ -474,6 +474,8 @@ *flags |= QEMUD_CMD_FLAG_DRIVE; if (strstr(help, "boot=on")) *flags |= QEMUD_CMD_FLAG_DRIVE_BOOT; + if (strstr(help, "IFF_VNET_HDR")) + *flags |= QEMUD_CMD_FLAG_VNET_HDR; if (ver >= 9000) *flags |= QEMUD_CMD_FLAG_VNC_COLON; } @@ -545,7 +547,8 @@ int **tapfds, int *ntapfds, virDomainNetDefPtr net, - int vlan) + int vlan, + int vnet_hdr) { virNetworkObjPtr network = NULL; char *brname; @@ -593,7 +596,7 @@ } if ((err = brAddTap(driver->brctl, brname, - &net->ifname, &tapfd))) { + &net->ifname, vnet_hdr, &tapfd))) { if (errno == ENOTSUP) { /* In this particular case, give a better diagnostic. */ qemudReportError(conn, NULL, NULL, VIR_ERR_INTERNAL_ERROR, @@ -1011,9 +1014,16 @@ case VIR_DOMAIN_NET_TYPE_NETWORK: case VIR_DOMAIN_NET_TYPE_BRIDGE: { - char *tap = qemudNetworkIfaceConnect(conn, driver, - tapfds, ntapfds, - net, vlan); + char *tap; + int vnet_hdr = 0; + + if (qemuCmdFlags & QEMUD_CMD_FLAG_VNET_HDR && + net->model && !strcmp(net->model, "virtio")) + vnet_hdr = 1; + + tap = qemudNetworkIfaceConnect(conn, driver, + tapfds, ntapfds, + net, vlan, vnet_hdr); if (tap == NULL) goto error; ADD_ARG(tap); Index: libvirt/src/qemu_conf.h =================================================================== --- libvirt.orig/src/qemu_conf.h 2008-08-13 15:40:34.000000000 +0100 +++ libvirt/src/qemu_conf.h 2008-08-13 15:41:15.000000000 +0100 @@ -47,6 +47,7 @@ QEMUD_CMD_FLAG_DRIVE = (1 << 3), QEMUD_CMD_FLAG_DRIVE_BOOT = (1 << 4), QEMUD_CMD_FLAG_NAME = (1 << 5), + QEMUD_CMD_FLAG_VNET_HDR = (1 << 6), }; /* Main driver state */

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[libvirt] PATCH: 0/7: Re-factor LXC driver
by Daniel P. Berrange 13 Aug '08

13 Aug '08

This is a long overdue followup to my previous set of patches to make the LXC driver use the new domain XML apis. Getting this merged is a blocker for the new libvirt release, now we've turned on LXC by default. Likewise we need to get OpenVZ fully ported to new XML before release too. The previous posting was here: http://www.redhat.com/archives/libvir-list/2008-July/msg00182.html Regards, Daniel -- |: Red Hat, Engineering, London -o- http://people.redhat.com/berrange/ :| |: http://libvirt.org -o- http://virt-manager.org -o- http://ovirt.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: GnuPG: 7D3B9505 -o- F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|

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[libvirt] virt-install?
by Jun Koi 13 Aug '08

13 Aug '08

Hi, I got the libvirt source code (cvs), and compiled. However, I cannot find the virt-install anywhere. Is it included inside libvirt? Thank you, Jun

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[libvirt] [PATCH] Change disk type 'dos' to 'msdos'
by Cole Robinson 13 Aug '08

13 Aug '08

parted doesn't seem to want the label 'dos', instead wanting 'msdos'. Patch is basically s/dos/msdos/ Thanks, Cole

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[libvirt] Re: virDomainMemoryPeek for Xen?
by Richard W.M. Jones 13 Aug '08

13 Aug '08

On Wed, Aug 13, 2008 at 01:19:42PM +0900, Jun Koi wrote: > According to the comment in your driver code for virDomainMemoryPeek, > libvirt is not currently supporting Xen. Why is that? As far as I see, > Xen is use the same GPL2 version as libvirt. > > I am thinking about implementing the driver for Xen, so have this question. It'd be really good to have a driver for this for libvirt. QEMU does virtual->physical translation for us, through the guest's CR3 & page tables. [This discussion will concentrate on x86 for the moment :-)] If you look at the qemu source, file target-i386/ helper2.c, function cpu_get_phys_page_debug, you will see the code they use to navigate through the 3 or 4 levels of page tables for i386 & x86-64 respectively. The QEMU memsave command made it almost trivial to write virDomainMemoryPeek (...VIR_MEMORY_VIRTUAL...); On Xen things are a bit different. You can map in physical pages from another guest using the libxc call xc_map_foreign_range. Note that you cannot just call xc_map_foreign_range because the libxc & libvirt licenses are _not_ compatible. So instead you'd need to do the underlying sequence of mmap / ioctl / munmap. (See tools/libxc/ xc_linux.c in the Xen source). But you still need to do virtual to physical page translation, either using the qemu source as an example, or using xc_translate_foreign_address as a guide (or just using the Intel Programmers Reference Manual and doing it from first principles). Another alternative is to implement virDomainMemoryPeek (...VIR_MEMORY_PHYSICAL...). It is not possible to implement this for QEMU at all, at least not without changing QEMU. Implementing this for Xen would be much easier because you don't need to do address translation, but it does push the problem of address translation up to the callers. Places to look in the QEMU source for inspiration: monitor.c:do_memory_save target-i386/helper2.c:cpu_get_phys_page_debug Other places to look in the Xen source for inspiration: tools/libxc/xc_linux.c tools/libxc/xc_pagetab.c tools/xentrace/xenctx.c (thanks Mark McLoughlin) Rich. -- Richard Jones, Emerging Technologies, Red Hat http://et.redhat.com/~rjones virt-top is 'top' for virtual machines. Tiny program with many powerful monitoring features, net stats, disk stats, logging, etc. http://et.redhat.com/~rjones/virt-top

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