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* xen/xenbus: Remove duplicate inclusion of asm/xen/hypervisor.hSachin Kamat2012-11-28
| | | | | | | asm/xen/hypervisor.h was included twice. Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* xen: xenbus: quirk uses x86 specific cpuidIan Campbell2012-10-19
| | | | | | | | | | This breaks on ARM. This quirk is not necessary on ARM because no hypervisors of that vintage exist for that architecture (port is too new). Signed-off-by: Ian Campbell <ian.campbell@citrix.com> [v1: Moved the ifdef inside the function per Jan Beulich suggestion] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* xen/xenbus: Fix compile warning.Konrad Rzeszutek Wilk2012-10-19
| | | | | | | We were missing the 'void' on the parameter arguments. Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* xen/pv-on-hvm kexec: add quirk for Xen 3.4 and shutdown watches.Konrad Rzeszutek Wilk2012-10-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The commit 254d1a3f02ebc10ccc6e4903394d8d3f484f715e, titled "xen/pv-on-hvm kexec: shutdown watches from old kernel" assumes that the XenBus backend can deal with reading of values from: "control/platform-feature-xs_reset_watches": ... a patch for xenstored is required so that it accepts the XS_RESET_WATCHES request from a client (see changeset 23839:42a45baf037d in xen-unstable.hg). Without the patch for xenstored the registration of watches will fail and some features of a PVonHVM guest are not available. The guest is still able to boot, but repeated kexec boots will fail." Sadly this is not true when using a Xen 3.4 hypervisor and booting a PVHVM guest. We end up hanging at: err = xenbus_scanf(XBT_NIL, "control", "platform-feature-xs_reset_watches", "%d", &supported); This can easily be seen with guests hanging at xenbus_init: NX (Execute Disable) protection: active SMBIOS 2.4 present. DMI: Xen HVM domU, BIOS 3.4.0 05/13/2011 Hypervisor detected: Xen HVM Xen version 3.4. Xen Platform PCI: I/O protocol version 1 ... snip .. calling xenbus_init+0x0/0x27e @ 1 Reverting the commit or using the attached patch fixes the issue. This fix checks whether the hypervisor is older than 4.0 and if so does not try to perform the read. Fixes-Oracle-Bug: 14708233 CC: stable@vger.kernel.org Acked-by: Olaf Hering <olaf@aepfle.de> [v2: Added a comment in the source code] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* xen/arm: compile and run xenbusStefano Stabellini2012-09-17
| | | | | | | | | | | | | | | | | | bind_evtchn_to_irqhandler can legitimately return 0 (irq 0): it is not an error. If Linux is running as an HVM domain and is running as Dom0, use xenstored_local_init to initialize the xenstore page and event channel. Changes in v4: - do not xs_reset_watches on dom0. Changes in v2: - refactor xenbus_init. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> [v5: Fixed case switch indentations] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* xen/pv-on-hvm kexec: shutdown watches from old kernelOlaf Hering2012-07-19
| | | | | | | | | | | | | | | | | | | | | | Add xs_reset_watches function to shutdown watches from old kernel after kexec boot. The old kernel does not unregister all watches in the shutdown path. They are still active, the double registration can not be detected by the new kernel. When the watches fire, unexpected events will arrive and the xenwatch thread will crash (jumps to NULL). An orderly reboot of a hvm guest will destroy the entire guest with all its resources (including the watches) before it is rebuilt from scratch, so the missing unregister is not an issue in that case. With this change the xenstored is instructed to wipe all active watches for the guest. However, a patch for xenstored is required so that it accepts the XS_RESET_WATCHES request from a client (see changeset 23839:42a45baf037d in xen-unstable.hg). Without the patch for xenstored the registration of watches will fail and some features of a PVonHVM guest are not available. The guest is still able to boot, but repeated kexec boots will fail. Signed-off-by: Olaf Hering <olaf@aepfle.de> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* Merge branch 'stable/for-linus-3.3' of ↵Linus Torvalds2012-01-10
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen * 'stable/for-linus-3.3' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen: (37 commits) xen/pciback: Expand the warning message to include domain id. xen/pciback: Fix "device has been assigned to X domain!" warning xen/pciback: Move the PCI_DEV_FLAGS_ASSIGNED ops to the "[un|]bind" xen/xenbus: don't reimplement kvasprintf via a fixed size buffer xenbus: maximum buffer size is XENSTORE_PAYLOAD_MAX xen/xenbus: Reject replies with payload > XENSTORE_PAYLOAD_MAX. Xen: consolidate and simplify struct xenbus_driver instantiation xen-gntalloc: introduce missing kfree xen/xenbus: Fix compile error - missing header for xen_initial_domain() xen/netback: Enable netback on HVM guests xen/grant-table: Support mappings required by blkback xenbus: Use grant-table wrapper functions xenbus: Support HVM backends xen/xenbus-frontend: Fix compile error with randconfig xen/xenbus-frontend: Make error message more clear xen/privcmd: Remove unused support for arch specific privcmp mmap xen: Add xenbus_backend device xen: Add xenbus device driver xen: Add privcmd device driver xen/gntalloc: fix reference counts on multi-page mappings ...
| * xen/xenbus: don't reimplement kvasprintf via a fixed size bufferIan Campbell2012-01-04
| | | | | | | | | | | | | | Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Cc: Haogang Chen <haogangchen@gmail.com> Acked-by: Jan Beulich <JBeulich@suse.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| * xen/xenbus: Reject replies with payload > XENSTORE_PAYLOAD_MAX.Ian Campbell2012-01-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Haogang Chen found out that: There is a potential integer overflow in process_msg() that could result in cross-domain attack. body = kmalloc(msg->hdr.len + 1, GFP_NOIO | __GFP_HIGH); When a malicious guest passes 0xffffffff in msg->hdr.len, the subsequent call to xb_read() would write to a zero-length buffer. The other end of this connection is always the xenstore backend daemon so there is no guest (malicious or otherwise) which can do this. The xenstore daemon is a trusted component in the system. However this seem like a reasonable robustness improvement so we should have it. And Ian when read the API docs found that: The payload length (len field of the header) is limited to 4096 (XENSTORE_PAYLOAD_MAX) in both directions. If a client exceeds the limit, its xenstored connection will be immediately killed by xenstored, which is usually catastrophic from the client's point of view. Clients (particularly domains, which cannot just reconnect) should avoid this. so this patch checks against that instead. This also avoids a potential integer overflow pointed out by Haogang Chen. Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Cc: Haogang Chen <haogangchen@gmail.com> CC: stable@kernel.org Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* | Revert "xen/pv-on-hvm kexec: add xs_reset_watches to shutdown watches from ↵Konrad Rzeszutek Wilk2011-12-19
|/ | | | | | | | | | | | | | | | old kernel" This reverts commit ddacf5ef684a655abe2bb50c4b2a5b72ae0d5e05. As when booting the kernel under Amazon EC2 as an HVM guest it ends up hanging during startup. Reverting this we loose the fix for kexec booting to the crash kernels. Fixes Canonical BZ #901305 (http://bugs.launchpad.net/bugs/901305) Tested-by: Alessandro Salvatori <sandr8@gmail.com> Reported-by: Stefan Bader <stefan.bader@canonical.com> Acked-by: Ian Campbell <Ian.Campbell@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* xen/pv-on-hvm:kexec: Fix implicit declaration of function 'xen_hvm_domain'Konrad Rzeszutek Wilk2011-09-26
| | | | | | | | | | | | Randy found a compile error when using make randconfig to trigger drivers/xen/xenbus/xenbus_xs.c:909:2: error: implicit declaration of function 'xen_hvm_domain' it is unclear which of the CONFIG options triggered this. This patch fixes the error. Reported-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* xen/pv-on-hvm kexec: add xs_reset_watches to shutdown watches from old kernelOlaf Hering2011-09-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Add new xs_reset_watches function to shutdown watches from old kernel after kexec boot. The old kernel does not unregister all watches in the shutdown path. They are still active, the double registration can not be detected by the new kernel. When the watches fire, unexpected events will arrive and the xenwatch thread will crash (jumps to NULL). An orderly reboot of a hvm guest will destroy the entire guest with all its resources (including the watches) before it is rebuilt from scratch, so the missing unregister is not an issue in that case. With this change the xenstored is instructed to wipe all active watches for the guest. However, a patch for xenstored is required so that it accepts the XS_RESET_WATCHES request from a client (see changeset 23839:42a45baf037d in xen-unstable.hg). Without the patch for xenstored the registration of watches will fail and some features of a PVonHVM guest are not available. The guest is still able to boot, but repeated kexec boots will fail. [v5: use xs_single instead of passing a dummy string to xs_talkv] [v4: ignore -EEXIST in xs_reset_watches] [v3: use XS_RESET_WATCHES instead of XS_INTRODUCE] [v2: move all code which deals with XS_INTRODUCE into xs_introduce() (based on feedback from Ian Campbell); remove casts from kvec assignment] Signed-off-by: Olaf Hering <olaf@aepfle.de> [v1: Redid the git description a bit] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* xen/pv-on-hvm kexec: prevent crash in xenwatch_thread() when stale watch ↵Olaf Hering2011-09-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | events arrive During repeated kexec boots xenwatch_thread() can crash because xenbus_watch->callback is cleared by xenbus_watch_path() if a node/token combo for a new watch happens to match an already registered watch from an old kernel. In this case xs_watch returns -EEXISTS, then register_xenbus_watch() does not remove the to-be-registered watch from the list of active watches but returns the -EEXISTS to the caller anyway. Because the watch is still active in xenstored it will cause an event which will arrive in the new kernel. process_msg() will find the encapsulated struct xenbus_watch in its list of registered watches and puts the "empty" watch handle in the queue for xenwatch_thread(). xenwatch_thread() then calls ->callback which was cleared earlier by xenbus_watch_path(). To prevent that crash in a guest running on an old xen toolstack remove the special -EEXIST handling. v2: - remove the EEXIST handing in register_xenbus_watch() instead of checking for ->callback in process_msg() Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Olaf Hering <olaf@aepfle.de>
* Merge branch 'xen/xenbus' into upstream/xenJeremy Fitzhardinge2010-08-04
|\ | | | | | | | | | | * xen/xenbus: implement O_NONBLOCK for /proc/xen/xenbus xenbus: do not hold transaction_mutex when returning to userspace
| * xenbus: do not hold transaction_mutex when returning to userspaceIan Campbell2009-11-03
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ================================================ [ BUG: lock held when returning to user space! ] ------------------------------------------------ xenstore-list/3522 is leaving the kernel with locks still held! 1 lock held by xenstore-list/3522: #0: (&xs_state.transaction_mutex){......}, at: [<c026dc6f>] xenbus_dev_request_and_reply+0x8f/0xa0 The canonical fix for this type of issue appears to be to maintain a count manually rather than using an rwsem so do that here. Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
* | xen: avoid allocation causing potential swap activity on the resume pathIan Campbell2010-06-03
|/ | | | | | | | | | | | | | | | | | | Since the device we are resuming could be the device containing the swap device we should ensure that the allocation cannot cause IO. On resume, this path is triggered when the running system tries to continue using its devices. If it cannot then the resume will fail; to try to avoid this we let it dip into the emergency pools. The majority of these changes were made when linux-2.6.18-xen.hg changeset e8b49cfbdac0 was ported upstream in a144ff09bc52ef3f3684ed23eadc9c7c0e57b3aa but somehow this hunk was dropped. Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Acked-by: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Stable Kernel <stable@kernel.org> # .32.x
* xen: use device model for suspending xenbus devicesIan Campbell2009-03-30
| | | | | Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
* xen: add xenfs to allow usermode <-> Xen interactionAlex Zeffertt2009-01-08
| | | | | | | | | | | | | | | The xenfs filesystem exports various interfaces to usermode. Initially this exports a file to allow usermode to interact with xenbus/xenstore. Traditionally this appeared in /proc/xen. Rather than extending procfs, this patch adds a backward-compat mountpoint on /proc/xen, and provides a xenfs filesystem which can be mounted there. Signed-off-by: Alex Zeffertt <alex.zeffertt@eu.citrix.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* xen: Avoid allocations causing swap activity on the resume pathIan Campbell2008-07-03
| | | | | | | | | | | | | | | | | | | | Avoid allocations causing swap activity on the resume path by preventing the allocations from doing IO and allowing them to access the emergency pools. These paths are used when a frontend device is trying to connect to its backend driver over Xenbus. These reconnections are triggered on demand by IO, so by definition there is already IO underway, and further IO would naturally deadlock. On resume, this path is triggered when the running system tries to continue using its devices. If it cannot then the resume will fail; to try to avoid this we let it dip into the emergency pools. [ linux-2.6.18-xen changesets e8b49cfbdac, fdb998e79aba ] Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* xenbus_xs.c: fix a use-after-freeAdrian Bunk2007-07-26
| | | | | | | | | This patch fixes an obvious use-after-free spotted by the Coverity checker. Signed-off-by: Adrian Bunk <bunk@stusta.de> Acked-by: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* xen: add the Xenbus sysfs and virtual device hotplug driverJeremy Fitzhardinge2007-07-18
This communicates with the machine control software via a registry residing in a controlling virtual machine. This allows dynamic creation, destruction and modification of virtual device configurations (network devices, block devices and CPUS, to name some examples). [ Greg, would you mind giving this a review? Thanks -J ] Signed-off-by: Ian Pratt <ian.pratt@xensource.com> Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk> Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Chris Wright <chrisw@sous-sol.org> Cc: Greg KH <greg@kroah.com>