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[libvirt] Re: [PATCH] Hardware watchdog patch, version 6 (was: Re: [Qemu-devel] [PATCH] Hardware watchdog patch, version 5)
by Hollis Blanchard 08 Apr '09

08 Apr '09

Hi Rich, your watchdog qemu patch is working fine for me (i6300esb, default reset behavior), but I was wondering... how should libvirt find out about the watchdog firing? At that point, I think the next step from libvirt is to send a VIR_DOMAIN_EVENT_STOPPED_CRASHED domain event, correct? -- Hollis Blanchard IBM Linux Technology Center

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[libvirt] Changing the QEMU svn VERSION string
by Anthony Liguori 08 Apr '09

08 Apr '09

Hi, I'd like to update the VERSION string in QEMU's svn tree. Right now, it's 0.10.0 and since we have a 0.10.2 release, that's somewhat confusing. I don't want to make it 0.11.0 either because that's not going to be reliable from a feature detection perspective. What I would like is to make it 0.11.0-devel or something similar to that. Being the nice guy I am, I thought I would check that this didn't make libvirt go bonkers :-) This is the relevant detection code in libvirt: if (sscanf(help, "QEMU PC emulator version %u.%u.%u (kvm-%u)", &major, &minor, &micro, &kvm_version) != 4) kvm_version = 0; if (!kvm_version && sscanf(help, "QEMU PC emulator version u.%u.%u", &major, &minor, &micro) != 3) goto cleanup2; If I change SVN to 0.11.0-devel, that's going to break the KVM string although the QEMU string will continue to work. Avi could potentially carry a patch to keep it 0.10.x and since kvm-%u will be used to identify features, that should keep things working. Anyone have any objections/suggestions? Regards, Anthony Liguori

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[libvirt] Thoughts on svirt configuration files.
by Daniel J Walsh 08 Apr '09

08 Apr '09

Currently we do not want to hard code virtual image names into libvirt, so libvirt and virtual-manager can use libselinux to get the default image label and process label. svirt_t and svirt_image_t. The idea was one policy writer might want his virtual images labeled differently than another. One problem with this is I added to interfaces one for the domain, and one for the image label. Now we realize we have other images. We have process Label - svirt_t:MCS Exclusive RW Image - svirt_image_t:MCS Shared RW Image - svirt_image_t:s0 Read Only Image - virt_content_t:s0 So I am suggesting that we remove the virtual_image_context file and allowing policy writers to define context in the virtual_domain_context files but have multiple records and multiple fields. Something like a space separated list where each field corresponds to above. system_u:system_r:svirt_t:s0 system_u:object_r:svirt_image_t:s0 system_u:object_r:svirt_image_t:s0 system_u:object_r:virt_content_t:s0 Then you could add optional types with similar fields system_u:system_r:svirt_nonet_t:s0 system_u:object_r:svirt_image_t:s0 system_u:object_r:svirt_image_t:s0 system_u:object_r:virt_content_t:s0 Since SELinux just returns a path, the virt team could choose the format of the file if a space separated list is not addequate. (xml?) Name Value Pairs? Policy writers would have to enter the format that is chosen. Thoughts? I am thinking we might eventually want to allow an admin to select dynamic labels but specify alternative types. So svirt_t would be default but if someone wanted svirt_nonet_t, they could choose that also and get separation with a different type.

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[libvirt] [PATCH 1/2] VirtualBox support
by Pritesh Kothari 08 Apr '09

08 Apr '09

Hi All, I have attached a patch which when applied on the HEAD as of today would allow virtualbox support in libvirt. It takes cares of all the stuff mentioned on the list earlier. Still if I have missed anything, please do tell me. The patch works very well with the VirtualBox OSE version and the 2.2 release. [PATCH 1/2] contains diff of files already in libvirt. [PATCH 2/2] contains new files needed for VirtualBox support. Regards, Pritesh

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[libvirt] [PATCH] lxc: fix veth off by 1 error
by Serge E. Hallyn 08 Apr '09

08 Apr '09

When not specifying a target for veth device, veth.c:getFreeVethName() is supposed to scan for unused veth devices in /sys/class/net. However, when it finds one, it bumps the index by one before returning it. So, if you have one container running, veth0 is passed into the container, veth1 is taken and still sitting in /sys/class/net. When you now start a second container, getFreeVethName() finds veth0 is unused, but returns 1. Now container creation dies becuase /sys/class/net/veth1 exists. Signed-off-by: Serge Hallyn <serue(a)us.ibm.com> --- src/veth.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-) diff --git a/src/veth.c b/src/veth.c index 93173e4..90c1dcb 100644 --- a/src/veth.c +++ b/src/veth.c @@ -35,12 +35,12 @@ static int getFreeVethName(char *veth, int maxLen, int startDev) { int rc = -1; - int devNum = startDev; + int devNum = startDev-1; char path[PATH_MAX]; do { - snprintf(path, PATH_MAX, "/sys/class/net/veth%d/", devNum); ++devNum; + snprintf(path, PATH_MAX, "/sys/class/net/veth%d/", devNum); } while (virFileExists(path)); snprintf(veth, maxLen, "veth%d", devNum); @@ -97,6 +97,7 @@ int vethCreate(char* veth1, int veth1MaxLen, while ((1 > strlen(veth2)) || STREQ(veth1, veth2)) { vethDev = getFreeVethName(veth2, veth2MaxLen, vethDev); + ++vethDev; DEBUG("assigned veth2: %s", veth2); } -- 1.6.2

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[libvirt] [PATCH 0/1] Trigger SCSI scans on pool refresh
by David Allan 07 Apr '09

07 Apr '09

This patch is a small piece of code that causes the SCSI midlayer to rescan all targets for new LUs by echoing "- - -" into /sys/class/scsi_host/hostN/scan It does not attempt to cause a LIP to be issued. Dave

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[libvirt] [PATCH] lxc: make the pivot_root more robust.
by Serge E. Hallyn 07 Apr '09

07 Apr '09

libvirt/lxc is broken on F11. The pivot_root() call returns -EINVAL. The below is one way we can fix it. I'm also sending another patch which takes the simpler approach of using chroot. However, chroot is trivially escapable (see for instance http://www.linuxsecurity.com/content/view/117632/49/) I don't know whether the typical libvirt user would care. If so, then the below patch is probably the way to go. >From 26cac415771a2d9712af0e1ce60a0bcb41b44665 Mon Sep 17 00:00:00 2001 From: root <root(a)localhost.localdomain> Date: Sat, 4 Apr 2009 22:49:20 -0400 Subject: [PATCH 1/1] lxc: make the pivot_root more robust. The libvirt lxc driver uses pivot_root instead of chroot, because the latter is trivially escapable. However, the pivot_root(2) system call can fail for several subtle reasons. Depending upon your distro init sequence you may get lucky and have the old recipe work, but on a Fedora 11 standard install, for instance, it will fail. Do a few more steps to make pivot_root hopefully always succeed. We mark / as MS_PRIVATE, create an empty tmpfs, and bind-mount the container root onto /new in that fs. In this way, we ensure two reasons for pivot_root to fail - namely old_root->parent being MS_SHARED and old_root and new_root being on the same fs - won't happen. Signed-off-by: Serge Hallyn <serue(a)us.ibm.com> --- src/lxc_container.c | 108 ++++++++++++++++++++++++++++++++++++++++----------- 1 files changed, 85 insertions(+), 23 deletions(-) diff --git a/src/lxc_container.c b/src/lxc_container.c index 3f17b8d..d3959f6 100644 --- a/src/lxc_container.c +++ b/src/lxc_container.c @@ -264,50 +264,113 @@ static int lxcContainerChildMountSort(const void *a, const void *b) return strcmp(*sb, *sa); } +#ifndef MS_REC +#define MS_REC 16384 +#endif + +#ifndef MNT_DETACH +#define MNT_DETACH 0x00000002 +#endif + +#ifndef MS_PRIVATE +#define MS_PRIVATE 1<<18 +#endif + static int lxcContainerPivotRoot(virDomainFSDefPtr root) { int rc; - char *oldroot; + char *oldroot = NULL, *newroot = NULL; - /* First step is to ensure the new root itself is - a mount point */ - if (mount(root->src, root->src, NULL, MS_BIND, NULL) < 0) { - virReportSystemError(NULL, errno, - _("failed to bind new root %s"), - root->src); - return -1; + /* root->parent must be private, so make / private. */ + if (mount("", "/", NULL, MS_PRIVATE|MS_REC, NULL) < 0) { + virReportSystemError(NULL, errno, "%s", + _("failed to make root private")); + goto err; } if (virAsprintf(&oldroot, "%s/.oldroot", root->src) < 0) { virReportOOMError(NULL); - return -1; + goto err; } if ((rc = virFileMakePath(oldroot)) < 0) { virReportSystemError(NULL, rc, _("failed to create %s"), oldroot); - VIR_FREE(oldroot); - return -1; + goto err; + } + + /* Create a tmpfs root since old and new roots must be + * on separate filesystems */ + if (mount("", oldroot, "tmpfs", 0, NULL) < 0) { + virReportSystemError(NULL, errno, + _("failed to mount empty tmpfs at %s"), + oldroot); + goto err; + } + + /* Create a directory called 'new' in tmpfs */ + if (virAsprintf(&newroot, "%s/new", oldroot) < 0) { + virReportOOMError(NULL); + goto err; + } + + if ((rc = virFileMakePath(newroot)) < 0) { + virReportSystemError(NULL, rc, + _("failed to create %s"), + newroot); + goto err; + } + + /* ... and mount our root onto it */ + if (mount(root->src, newroot, NULL, MS_BIND|MS_REC, NULL) < 0) { + virReportSystemError(NULL, errno, + _("failed to bind new root %s into tmpfs"), + root->src); + goto err; + } + + /* Now we chroot into the tmpfs, then pivot into the + * root->src bind-mounted onto '/new' */ + if (chroot(oldroot) < 0) { + virReportSystemError(NULL, errno, "%s", + _("failed to chroot into tmpfs")); + goto err; + } + + if (chdir("/new") < 0) { + virReportSystemError(NULL, errno, "%s", + _("failed to chdir into /new on tmpfs")); + goto err; } /* The old root directory will live at /.oldroot after * this and will soon be unmounted completely */ - if (pivot_root(root->src, oldroot) < 0) { - virReportSystemError(NULL, errno, - _("failed to pivot root %s to %s"), - oldroot, root->src); - VIR_FREE(oldroot); - return -1; + if (pivot_root(".", ".oldroot") < 0) { + virReportSystemError(NULL, errno, "%s", + _("failed to pivot root")); + goto err; } - VIR_FREE(oldroot); /* CWD is undefined after pivot_root, so go to / */ - if (chdir("/") < 0) { - return -1; + if (chdir("/") < 0) + goto err; + + if (umount2(".oldroot", MNT_DETACH) < 0) { + virReportSystemError(NULL, errno, "%s", + _("failed to lazily unmount old root")); + goto err; } + VIR_FREE(oldroot); + VIR_FREE(newroot); + return 0; + +err: + if (oldroot) VIR_FREE(oldroot); + if (newroot) VIR_FREE(newroot); + return -1; } static int lxcContainerPopulateDevices(void) @@ -349,10 +412,9 @@ static int lxcContainerPopulateDevices(void) _("cannot create /dev/pts")); return -1; } - if (mount("/.oldroot/dev/pts", "/dev/pts", NULL, - MS_MOVE, NULL) < 0) { + if (mount("devpts", "/dev/pts", "devpts", 0, NULL) < 0) { virReportSystemError(NULL, errno, "%s", - _("failed to move /dev/pts into container")); + _("failed to mount /dev/pts in container")); return -1; } -- 1.6.2

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[libvirt] [PATCH] lxc: use chroot instead of pivot_root
by Serge E. Hallyn 06 Apr '09

06 Apr '09

This is an alternative to the pivot_root patch which I just sent. It has the advantage of being much simpler. It also won't have a problem with the container's / being a read-only mount. It has the disadvantage, of course, of being escapable. >From a91bca7f60f27e8fbdb4e3bacf3232a6cbb630d3 Mon Sep 17 00:00:00 2001 From: root <root(a)localhost.localdomain> Date: Fri, 3 Apr 2009 23:35:24 -0400 Subject: [PATCH 1/1] lxc: use chroot instead of pivot_root pivot_root is too fragile. For instance, if the container's / is read-only, we can't create .oldroot. Maybe we're happy telling users that if they can't create .oldroot at container create time, then they must make sure it exists ahead of time. Or, maybe we're ok with chroot being escapable, and should just go this simple route. Signed-off-by: Serge Hallyn <serue(a)us.ibm.com> --- src/lxc_container.c | 75 +++++++++++++-------------------------------------- 1 files changed, 19 insertions(+), 56 deletions(-) diff --git a/src/lxc_container.c b/src/lxc_container.c index 3f17b8d..142ed4d 100644 --- a/src/lxc_container.c +++ b/src/lxc_container.c @@ -264,52 +264,6 @@ static int lxcContainerChildMountSort(const void *a, const void *b) return strcmp(*sb, *sa); } -static int lxcContainerPivotRoot(virDomainFSDefPtr root) -{ - int rc; - char *oldroot; - - /* First step is to ensure the new root itself is - a mount point */ - if (mount(root->src, root->src, NULL, MS_BIND, NULL) < 0) { - virReportSystemError(NULL, errno, - _("failed to bind new root %s"), - root->src); - return -1; - } - - if (virAsprintf(&oldroot, "%s/.oldroot", root->src) < 0) { - virReportOOMError(NULL); - return -1; - } - - if ((rc = virFileMakePath(oldroot)) < 0) { - virReportSystemError(NULL, rc, - _("failed to create %s"), - oldroot); - VIR_FREE(oldroot); - return -1; - } - - /* The old root directory will live at /.oldroot after - * this and will soon be unmounted completely */ - if (pivot_root(root->src, oldroot) < 0) { - virReportSystemError(NULL, errno, - _("failed to pivot root %s to %s"), - oldroot, root->src); - VIR_FREE(oldroot); - return -1; - } - VIR_FREE(oldroot); - - /* CWD is undefined after pivot_root, so go to / */ - if (chdir("/") < 0) { - return -1; - } - - return 0; -} - static int lxcContainerPopulateDevices(void) { int i; @@ -349,10 +303,9 @@ static int lxcContainerPopulateDevices(void) _("cannot create /dev/pts")); return -1; } - if (mount("/.oldroot/dev/pts", "/dev/pts", NULL, - MS_MOVE, NULL) < 0) { + if (mount("devpts", "/dev/pts", "devpts", 0, NULL) < 0) { virReportSystemError(NULL, errno, "%s", - _("failed to move /dev/pts into container")); + _("failed to mount /dev/pts in container")); return -1; } @@ -461,15 +414,25 @@ static int lxcContainerUnmountOldFS(void) } -/* Got a FS mapped to /, we're going the pivot_root - * approach to do a better-chroot-than-chroot - * this is based on this thread http://lkml.org/lkml/2008/3/5/29 - */ -static int lxcContainerSetupPivotRoot(virDomainDefPtr vmDef, +/* Got a FS mapped to /, now chroot. + * pivot_root would work, but requires too much hand-holding + * (especially, old_root->parent must not be shared) */ +static int lxcContainerSetupChroot(virDomainDefPtr vmDef, virDomainFSDefPtr root) { - if (lxcContainerPivotRoot(root) < 0) + if (chdir(root->src) < 0) { + virReportSystemError(NULL, errno, + _("failed to chdir to %s"), + root->src); + return -1; + } + + if (chroot(root->src) < 0) { + virReportSystemError(NULL, errno, + _("failed to chroot to %s"), + root->src); return -1; + } if (virFileMakePath("/proc") < 0 || mount("none", "/proc", "proc", 0, NULL) < 0) { @@ -537,7 +500,7 @@ static int lxcContainerSetupMounts(virDomainDefPtr vmDef) } if (root) - return lxcContainerSetupPivotRoot(vmDef, root); + return lxcContainerSetupChroot(vmDef, root); else return lxcContainerSetupExtraMounts(vmDef); } -- 1.6.2

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[libvirt] VM cpuTime discrepancy
by Zvi Dubitzky 06 Apr '09

06 Apr '09

The cpuTime of a VM reported by kvm72 is ok (real seconds ) while that reported by kvm-84 is not. Are you aware of this . Did you talk to kvm and was it fixed in latest kvm releases since 84 ? I access cpuTime via libvirt . (same version in both cases) . thanks Zvi Dubitzky Virtualization and System Architecture Email:dubi@il.ibm.com IBM Haifa Research Laboratory Phone: +972-4-8296182 Haifa, 31905, ISRAEL

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[libvirt] libvirt.org down
by Daniel Veillard 06 Apr '09

06 Apr '09

As Jim found out there is a problem on the libvirt.org box, I don't know exactly what's is going on, and I will go anc check the box tomorrow at 7am EST. Sorry for the inconvenience, and thanks Jim for raising the issue ! Daniel -- Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/ daniel(a)veillard.com | Rpmfind RPM search engine http://rpmfind.net/ http://veillard.com/ | virtualization library http://libvirt.org/

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