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* Merge tag 'for-linus-4.15-rc1-tag' of ↵Linus Torvalds2017-11-161-1/+98
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull xen updates from Juergen Gross: "Xen features and fixes for v4.15-rc1 Apart from several small fixes it contains the following features: - a series by Joao Martins to add vdso support of the pv clock interface - a series by Juergen Gross to add support for Xen pv guests to be able to run on 5 level paging hosts - a series by Stefano Stabellini adding the Xen pvcalls frontend driver using a paravirtualized socket interface" * tag 'for-linus-4.15-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (34 commits) xen/pvcalls: fix potential endless loop in pvcalls-front.c xen/pvcalls: Add MODULE_LICENSE() MAINTAINERS: xen, kvm: track pvclock-abi.h changes x86/xen/time: setup vcpu 0 time info page x86/xen/time: set pvclock flags on xen_time_init() x86/pvclock: add setter for pvclock_pvti_cpu0_va ptp_kvm: probe for kvm guest availability xen/privcmd: remove unused variable pageidx xen: select grant interface version xen: update arch/x86/include/asm/xen/cpuid.h xen: add grant interface version dependent constants to gnttab_ops xen: limit grant v2 interface to the v1 functionality xen: re-introduce support for grant v2 interface xen: support priv-mapping in an HVM tools domain xen/pvcalls: remove redundant check for irq >= 0 xen/pvcalls: fix unsigned less than zero error check xen/time: Return -ENODEV from xen_get_wallclock() xen/pvcalls-front: mark expected switch fall-through xen: xenbus_probe_frontend: mark expected switch fall-throughs xen/time: do not decrease steal time after live migration on xen ...
| * x86/xen/time: setup vcpu 0 time info pageJoao Martins2017-11-081-1/+89
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In order to support pvclock vdso on xen we need to setup the time info page for vcpu 0 and register the page with Xen using the VCPUOP_register_vcpu_time_memory_area hypercall. This hypercall will also forcefully update the pvti which will set some of the necessary flags for vdso. Afterwards we check if it supports the PVCLOCK_TSC_STABLE_BIT flag which is mandatory for having vdso/vsyscall support. And if so, it will set the cpu 0 pvti that will be later on used when mapping the vdso image. The xen headers are also updated to include the new hypercall for registering the secondary vcpu_time_info struct. Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Reviewed-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
| * x86/xen/time: set pvclock flags on xen_time_init()Joao Martins2017-11-081-0/+9
| | | | | | | | | | | | | | | | | | | | Specifically check for PVCLOCK_TSC_STABLE_BIT and if this bit is set, then set it too on pvclock flags. This allows Xen clocksource to use it and thus speeding up xen_clocksource_read() callers (i.e. sched_clock()) Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
| * xen/time: Return -ENODEV from xen_get_wallclock()Boris Ostrovsky2017-11-031-1/+1
| | | | | | | | | | | | | | | | | | For any other error sync_cmos_clock() will reschedule itself every second or so, for no good reason. Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
* | License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman2017-11-021-0/+1
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* xen/x86: Don't BUG on CPU0 offliningVitaly Kuznetsov2017-07-231-1/+0
| | | | | | | | | | | CONFIG_BOOTPARAM_HOTPLUG_CPU0 allows to offline CPU0 but Xen HVM guests BUG() in xen_teardown_timer(). Remove the BUG_ON(), this is probably a leftover from ancient times when CPU0 hotplug was impossible, it works just fine for HVM. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Acked-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
* xen/x86: Do not call xen_init_time_ops() until shared_info is initializedBoris Ostrovsky2017-05-051-1/+1
| | | | | | | | | | | | | | | Routines that are set by xen_init_time_ops() use shared_info's pvclock_vcpu_time_info area. This area is not properly available until shared_info is mapped in xen_setup_shared_info(). This became especially problematic due to commit dd759d93f4dd ("x86/timers: Add simple udelay calibration") where we end up reading tsc_to_system_mul from xen_dummy_shared_info (i.e. getting zero value) and then trying to divide by it in pvclock_tsc_khz(). Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
* xen: Revert commits da72ff5bfcb0 and 72a9b186292dBoris Ostrovsky2017-05-021-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Recent discussion (http://marc.info/?l=xen-devel&m=149192184523741) established that commit 72a9b186292d ("xen: Remove event channel notification through Xen PCI platform device") (and thus commit da72ff5bfcb0 ("partially revert "xen: Remove event channel notification through Xen PCI platform device"")) are unnecessary and, in fact, prevent HVM guests from booting on Xen releases prior to 4.0 Therefore we revert both of those commits. The summary of that discussion is below: Here is the brief summary of the current situation: Before the offending commit (72a9b186292): 1) INTx does not work because of the reset_watches path. 2) The reset_watches path is only taken if you have Xen > 4.0 3) The Linux Kernel by default will use vector inject if the hypervisor support. So even INTx does not work no body running the kernel with Xen > 4.0 would notice. Unless he explicitly disabled this feature either in the kernel or in Xen (and this can only be disabled by modifying the code, not user-supported way to do it). After the offending commit (+ partial revert): 1) INTx is no longer support for HVM (only for PV guests). 2) Any HVM guest The kernel will not boot on Xen < 4.0 which does not have vector injection support. Since the only other mode supported is INTx which. So based on this summary, I think before commit (72a9b186292) we were in much better position from a user point of view. Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
* x86/xen/time: Set ->min_delta_ticks and ->max_delta_ticksNicolai Stange2017-04-141-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In preparation for making the clockevents core NTP correction aware, all clockevent device drivers must set ->min_delta_ticks and ->max_delta_ticks rather than ->min_delta_ns and ->max_delta_ns: a clockevent device's rate is going to change dynamically and thus, the ratio of ns to ticks ceases to stay invariant. Make the x86 arch's xen clockevent driver initialize these fields properly. This patch alone doesn't introduce any change in functionality as the clockevents core still looks exclusively at the (untouched) ->min_delta_ns and ->max_delta_ns. As soon as this has changed, a followup patch will purge the initialization of ->min_delta_ns and ->max_delta_ns from this driver. Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Juergen Gross <jgross@suse.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: x86@kernel.org Cc: xen-devel@lists.xenproject.org Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Nicolai Stange <nicstange@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
* clocksource: Use a plain u64 instead of cycle_tThomas Gleixner2016-12-251-3/+3
| | | | | | | | | | | | | | | | | | | | | There is no point in having an extra type for extra confusion. u64 is unambiguous. Conversion was done with the following coccinelle script: @rem@ @@ -typedef u64 cycle_t; @fix@ typedef cycle_t; @@ -cycle_t +u64 Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: John Stultz <john.stultz@linaro.org>
* xen: Remove event channel notification through Xen PCI platform deviceKarimAllah Ahmed2016-09-301-5/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Ever since commit 254d1a3f02eb ("xen/pv-on-hvm kexec: shutdown watches from old kernel") using the INTx interrupt from Xen PCI platform device for event channel notification would just lockup the guest during bootup. postcore_initcall now calls xs_reset_watches which will eventually try to read a value from XenStore and will get stuck on read_reply at XenBus forever since the platform driver is not probed yet and its INTx interrupt handler is not registered yet. That means that the guest can not be notified at this moment of any pending event channels and none of the per-event handlers will ever be invoked (including the XenStore one) and the reply will never be picked up by the kernel. The exact stack where things get stuck during xenbus_init: -xenbus_init -xs_init -xs_reset_watches -xenbus_scanf -xenbus_read -xs_single -xs_single -xs_talkv Vector callbacks have always been the favourite event notification mechanism since their introduction in commit 38e20b07efd5 ("x86/xen: event channels delivery on HVM.") and the vector callback feature has always been advertised for quite some time by Xen that's why INTx was broken for several years now without impacting anyone. Luckily this also means that event channel notification through INTx is basically dead-code which can be safely removed without impacting anybody since it has been effectively disabled for more than 4 years with nobody complaining about it (at least as far as I'm aware of). This commit removes event channel notification through Xen PCI platform device. Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Juergen Gross <jgross@suse.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: x86@kernel.org Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Julien Grall <julien.grall@citrix.com> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Ross Lagerwall <ross.lagerwall@citrix.com> Cc: xen-devel@lists.xenproject.org Cc: linux-kernel@vger.kernel.org Cc: linux-pci@vger.kernel.org Cc: Anthony Liguori <aliguori@amazon.com> Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
* xen: add static initialization of steal_clock op to xen_time_opsJuergen Gross2016-07-261-0/+1
| | | | | | | | | | pv_time_ops might be overwritten with xen_time_ops after the steal_clock operation has been initialized already. To prevent calling a now uninitialized function pointer add the steal_clock static initialization to xen_time_ops. Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
* x86/xen: use xen_vcpu_id mapping for HYPERVISOR_vcpu_opVitaly Kuznetsov2016-07-251-6/+12
| | | | | | | | | | | | | | | | | | HYPERVISOR_vcpu_op() passes Linux's idea of vCPU id as a parameter while Xen's idea is expected. In some cases these ideas diverge so we need to do remapping. Convert all callers of HYPERVISOR_vcpu_op() to use xen_vcpu_nr(). Leave xen_fill_possible_map() and xen_filter_cpu_maps() intact as they're only being called by PV guests before perpu areas are initialized. While the issue could be solved by switching to early_percpu for xen_vcpu_id I think it's not worth it: PV guests will probably never get to the point where their idea of vCPU id diverges from Xen's. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
* xen: add steal_clock support on x86Juergen Gross2016-07-061-42/+2
| | | | | | | | | | | | | | | | The pv_time_ops structure contains a function pointer for the "steal_clock" functionality used only by KVM and Xen on ARM. Xen on x86 uses its own mechanism to account for the "stolen" time a thread wasn't able to run due to hypervisor scheduling. Add support in Xen arch independent time handling for this feature by moving it out of the arm arch into drivers/xen and remove the x86 Xen hack. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
* xen/x86: don't lose event interruptsStefano Stabellini2016-05-241-3/+3
| | | | | | | | | | | | | | | | | On slow platforms with unreliable TSC, such as QEMU emulated machines, it is possible for the kernel to request the next event in the past. In that case, in the current implementation of xen_vcpuop_clockevent, we simply return -ETIME. To be precise the Xen returns -ETIME and we pass it on. However the result of this is a missed event, which simply causes the kernel to hang. Instead it is better to always ask the hypervisor for a timer event, even if the timeout is in the past. That way there are no lost interrupts and the kernel survives. To do that, remove the VCPU_SSHOTTMR_future flag. Signed-off-by: Stefano Stabellini <sstabellini@kernel.org> Acked-by: Juergen Gross <jgross@suse.com>
* xen/x86: convert remaining timespec to timespec64 in xen_pvclock_gtod_notifyStefano Stabellini2015-12-211-2/+2
| | | | | Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
* xen/x86: support XENPF_settime64Stefano Stabellini2015-12-211-7/+28
| | | | | | | | | | | | | | Try XENPF_settime64 first, if it is not available fall back to XENPF_settime32. No need to call __current_kernel_time() when all the info needed are already passed via the struct timekeeper * argument. Return NOTIFY_BAD in case of errors. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
* xen: introduce XENPF_settime64Stefano Stabellini2015-12-211-4/+4
| | | | | | | | | Rename the current XENPF_settime hypercall and related struct to XENPF_settime32. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
* xen: rename dom0_op to platform_opStefano Stabellini2015-12-211-1/+1
| | | | | | | | | The dom0_op hypercall has been renamed to platform_op since Xen 3.2, which is ancient, and modern upstream Linux kernels cannot run as dom0 and it anymore anyway. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
* xen: move xen_setup_runstate_info and get_runstate_snapshot to ↵Stefano Stabellini2015-12-211-75/+1
| | | | | | | | drivers/xen/time.c Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Acked-by: Ian Campbell <ian.campbell@citrix.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* x86/xen/time: Migrate to new set-state interfaceViresh Kumar2015-07-301-49/+31
| | | | | | | | | | | | | | | | | | | | Migrate xen driver to the new 'set-state' interface provided by clockevents core, the earlier 'set-mode' interface is marked obsolete now. This also enables us to implement callbacks for new states of clockevent devices, for example: ONESHOT_STOPPED. Callbacks aren't implemented for modes where we weren't doing anything. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Cc: linaro-kernel@lists.linaro.org Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: xen-devel@lists.xenproject.org (moderated list:XEN HYPERVISOR INTERFACE) Link: http://lkml.kernel.org/r/881eea6e1a3d483cd33e044cd34827cce26a57fd.1437042675.git.viresh.kumar@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* x86/xen: prefer TSC over xen clocksource for dom0Palik, Imre2015-01-201-0/+4
| | | | | | | | | | | | | | | | In Dom0's the use of the TSC clocksource (whenever it is stable enough to be used) instead of the Xen clocksource should not cause any issues, as Dom0 VMs never live-migrated. The TSC clocksource is somewhat more efficient than the Xen paravirtualised clocksource, thus it should have higher rating. This patch decreases the rating of the Xen clocksource in Dom0s to 275. Which is half-way between the rating of the TSC clocksource (300) and the hpet clocksource (250). Cc: Anthony Liguori <aliguori@amazon.com> Signed-off-by: Imre Palik <imrep@amazon.de> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
* x86/xen: avoid freeing static 'name' when kasprintf() failsVitaly Kuznetsov2015-01-081-11/+5
| | | | | | | | | | | | | | In case kasprintf() fails in xen_setup_timer() we assign name to the static string "<timer kasprintf failed>". We, however, don't check that fact before issuing kfree() in xen_teardown_timer(), kernel is supposed to crash with 'kernel BUG at mm/slub.c:3341!' Solve the issue by making name a fixed length string inside struct xen_clock_event_device. 16 bytes should be enough. Suggested-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
* x86/xen: Remove unnecessary BUG_ON(preemptible()) in xen_setup_timer()Boris Ostrovsky2014-12-231-2/+0
| | | | | | | | | There is no reason for having it and, with commit 250a1ac685f1 ("x86, smpboot: Remove pointless preempt_disable() in native_smp_prepare_cpus()"), it prevents HVM guests from booting. Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
* x86/xen: Fix incorrect per_cpu accessor in xen_clocksource_read()Boris Ostrovsky2014-10-231-1/+1
| | | | | | | | | | | | Commit 89cbc76768c2 ("x86: Replace __get_cpu_var uses") replaced __get_cpu_var() with this_cpu_ptr() in xen_clocksource_read() in such a way that instead of accessing a structure pointed to by a per-cpu pointer we are trying to get to a per-cpu structure. __this_cpu_read() of the pointer is the more appropriate accessor. Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
* x86: Replace __get_cpu_var usesChristoph Lameter2014-08-261-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | __get_cpu_var() is used for multiple purposes in the kernel source. One of them is address calculation via the form &__get_cpu_var(x). This calculates the address for the instance of the percpu variable of the current processor based on an offset. Other use cases are for storing and retrieving data from the current processors percpu area. __get_cpu_var() can be used as an lvalue when writing data or on the right side of an assignment. __get_cpu_var() is defined as : #define __get_cpu_var(var) (*this_cpu_ptr(&(var))) __get_cpu_var() always only does an address determination. However, store and retrieve operations could use a segment prefix (or global register on other platforms) to avoid the address calculation. this_cpu_write() and this_cpu_read() can directly take an offset into a percpu area and use optimized assembly code to read and write per cpu variables. This patch converts __get_cpu_var into either an explicit address calculation using this_cpu_ptr() or into a use of this_cpu operations that use the offset. Thereby address calculations are avoided and less registers are used when code is generated. Transformations done to __get_cpu_var() 1. Determine the address of the percpu instance of the current processor. DEFINE_PER_CPU(int, y); int *x = &__get_cpu_var(y); Converts to int *x = this_cpu_ptr(&y); 2. Same as #1 but this time an array structure is involved. DEFINE_PER_CPU(int, y[20]); int *x = __get_cpu_var(y); Converts to int *x = this_cpu_ptr(y); 3. Retrieve the content of the current processors instance of a per cpu variable. DEFINE_PER_CPU(int, y); int x = __get_cpu_var(y) Converts to int x = __this_cpu_read(y); 4. Retrieve the content of a percpu struct DEFINE_PER_CPU(struct mystruct, y); struct mystruct x = __get_cpu_var(y); Converts to memcpy(&x, this_cpu_ptr(&y), sizeof(x)); 5. Assignment to a per cpu variable DEFINE_PER_CPU(int, y) __get_cpu_var(y) = x; Converts to __this_cpu_write(y, x); 6. Increment/Decrement etc of a per cpu variable DEFINE_PER_CPU(int, y); __get_cpu_var(y)++ Converts to __this_cpu_inc(y) Cc: Thomas Gleixner <tglx@linutronix.de> Cc: x86@kernel.org Acked-by: H. Peter Anvin <hpa@linux.intel.com> Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* x86/xen: resume timer irqs earlyDavid Vrabel2014-08-111-1/+1
| | | | | | | | | | | | | | | | | | | | | If the timer irqs are resumed during device resume it is possible in certain circumstances for the resume to hang early on, before device interrupts are resumed. For an Ubuntu 14.04 PVHVM guest this would occur in ~0.5% of resume attempts. It is not entirely clear what is occuring the point of the hang but I think a task necessary for the resume calls schedule_timeout(), waiting for a timer interrupt (which never arrives). This failure may require specific tasks to be running on the other VCPUs to trigger (processes are not frozen during a suspend/resume if PREEMPT is disabled). Add IRQF_EARLY_RESUME to the timer interrupts so they are resumed in syscore_resume(). Signed-off-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: stable@vger.kernel.org
* xen/x86: set VIRQ_TIMER priority to maximumDavid Vrabel2014-01-061-0/+1
| | | | | | | | | | | | | Commit bee980d9e (xen/events: Handle VIRQ_TIMER before any other hardirq in event loop) effectively made the VIRQ_TIMER the highest priority event when using the 2-level ABI. Set the VIRQ_TIMER priority to the highest so this behaviour is retained when using the FIFO-based ABI. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
* x86/xen: remove deprecated IRQF_DISABLEDMichael Opdenacker2013-11-061-2/+1
| | | | | | | | This patch proposes to remove the IRQF_DISABLED flag from x86/xen code. It's a NOOP since 2.6.35 and it will be removed one day. Signed-off-by: Michael Opdenacker <michael.opdenacker@free-electrons.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* Merge branch 'timers-core-for-linus' of ↵Linus Torvalds2013-07-061-15/+43
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer core updates from Thomas Gleixner: "The timer changes contain: - posix timer code consolidation and fixes for odd corner cases - sched_clock implementation moved from ARM to core code to avoid duplication by other architectures - alarm timer updates - clocksource and clockevents unregistration facilities - clocksource/events support for new hardware - precise nanoseconds RTC readout (Xen feature) - generic support for Xen suspend/resume oddities - the usual lot of fixes and cleanups all over the place The parts which touch other areas (ARM/XEN) have been coordinated with the relevant maintainers. Though this results in an handful of trivial to solve merge conflicts, which we preferred over nasty cross tree merge dependencies. The patches which have been committed in the last few days are bug fixes plus the posix timer lot. The latter was in akpms queue and next for quite some time; they just got forgotten and Frederic collected them last minute." * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (59 commits) hrtimer: Remove unused variable hrtimers: Move SMP function call to thread context clocksource: Reselect clocksource when watchdog validated high-res capability posix-cpu-timers: don't account cpu timer after stopped thread runtime accounting posix_timers: fix racy timer delta caching on task exit posix-timers: correctly get dying task time sample in posix_cpu_timer_schedule() selftests: add basic posix timers selftests posix_cpu_timers: consolidate expired timers check posix_cpu_timers: consolidate timer list cleanups posix_cpu_timer: consolidate expiry time type tick: Sanitize broadcast control logic tick: Prevent uncontrolled switch to oneshot mode tick: Make oneshot broadcast robust vs. CPU offlining x86: xen: Sync the CMOS RTC as well as the Xen wallclock x86: xen: Sync the wallclock when the system time is set timekeeping: Indicate that clock was set in the pvclock gtod notifier timekeeping: Pass flags instead of multiple bools to timekeeping_update() xen: Remove clock_was_set() call in the resume path hrtimers: Support resuming with two or more CPUs online (but stopped) timer: Fix jiffies wrap behavior of round_jiffies_common() ...
| * x86: xen: Sync the CMOS RTC as well as the Xen wallclockDavid Vrabel2013-06-281-19/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Adjustments to Xen's persistent clock via update_persistent_clock() don't actually persist, as the Xen wallclock is a software only clock and modifications to it do not modify the underlying CMOS RTC. The x86_platform.set_wallclock hook is there to keep the hardware RTC synchronized. On a guest this is pointless. On Dom0 we can use the native implementaion which actually updates the hardware RTC, but we still need to keep the software emulation of RTC for the guests up to date. The subscription to the pvclock_notifier allows us to emulate this easily. The notifier is called at every tick and when the clock was set. Right now we only use that notifier when the clock was set, but due to the fact that it is called periodically from the timekeeping update code, we can utilize it to emulate the NTP driven drift compensation of update_persistant_clock() for the Xen wall (software) clock. Add a 11 minutes periodic update to the pvclock_gtod notifier callback to achieve that. The static variable 'next' which maintains that 11 minutes update cycle is protected by the core code serialization so there is no need to add a Xen specific serialization mechanism. [ tglx: Massaged changelog and added a few comments ] Signed-off-by: David Vrabel <david.vrabel@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: John Stultz <john.stultz@linaro.org> Cc: <xen-devel@lists.xen.org> Link: http://lkml.kernel.org/r/1372329348-20841-6-git-send-email-david.vrabel@citrix.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * x86: xen: Sync the wallclock when the system time is setDavid Vrabel2013-06-281-0/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently the Xen wallclock is only updated every 11 minutes if NTP is synchronized to its clock source (using the sync_cmos_clock() work). If a guest is started before NTP is synchronized it may see an incorrect wallclock time. Use the pvclock_gtod notifier chain to receive a notification when the system time has changed and update the wallclock to match. This chain is called on every timer tick and we want to avoid an extra (expensive) hypercall on every tick. Because dom0 has historically never provided a very accurate wallclock and guests do not expect one, we can do this simply: the wallclock is only updated if the clock was set. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: John Stultz <john.stultz@linaro.org> Cc: <xen-devel@lists.xen.org> Link: http://lkml.kernel.org/r/1372329348-20841-5-git-send-email-david.vrabel@citrix.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * x86: Increase precision of x86_platform.get/set_wallclock()David Vrabel2013-05-281-13/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | All the virtualized platforms (KVM, lguest and Xen) have persistent wallclocks that have more than one second of precision. read_persistent_wallclock() and update_persistent_wallclock() allow for nanosecond precision but their implementation on x86 with x86_platform.get/set_wallclock() only allows for one second precision. This means guests may see a wallclock time that is off by up to 1 second. Make set_wallclock() and get_wallclock() take a struct timespec parameter (which allows for nanosecond precision) so KVM and Xen guests may start with a more accurate wallclock time and a Xen dom0 can maintain a more accurate wallclock for guests. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
* | xen/time: remove blocked time accounting from xen "clockchip"Laszlo Ersek2013-06-281-15/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ... because the "clock_event_device framework" already accounts for idle time through the "event_handler" function pointer in xen_timer_interrupt(). The patch is intended as the completion of [1]. It should fix the double idle times seen in PV guests' /proc/stat [2]. It should be orthogonal to stolen time accounting (the removed code seems to be isolated). The approach may be completely misguided. [1] https://lkml.org/lkml/2011/10/6/10 [2] http://lists.xensource.com/archives/html/xen-devel/2010-08/msg01068.html John took the time to retest this patch on top of v3.10 and reported: "idle time is correctly incremented for pv and hvm for the normal case, nohz=off and nohz=idle." so lets put this patch in. CC: stable@vger.kernel.org Signed-off-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: John Haxby <john.haxby@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* | xen/time: Free onlined per-cpu data structure if we want to online it again.Konrad Rzeszutek Wilk2013-06-101-13/+16
| | | | | | | | | | | | | | | | | | | | | | If the per-cpu time data structure has been onlined already and we are trying to online it again, then free the previous copy before blindly over-writting it. A developer naturally should not call this function multiple times but just in case. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* | xen/time: Check that the per_cpu data structure has data before freeing.Konrad Rzeszutek Wilk2013-06-101-4/+7
| | | | | | | | | | | | | | | | We don't check whether the per_cpu data structure has actually been freed in the past. This checks it and if it has been freed in the past then just continues on without double-freeing. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* | xen/time: Don't leak interrupt name when offlining.Konrad Rzeszutek Wilk2013-06-101-1/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When the user does: echo 0 > /sys/devices/system/cpu/cpu1/online echo 1 > /sys/devices/system/cpu/cpu1/online kmemleak reports: kmemleak: 7 new suspected memory leaks (see /sys/kernel/debug/kmemleak) One of the leaks is from xen/time: unreferenced object 0xffff88003fa51280 (size 32): comm "swapper/0", pid 1, jiffies 4294667339 (age 1027.789s) hex dump (first 32 bytes): 74 69 6d 65 72 31 00 00 00 00 00 00 00 00 00 00 timer1.......... 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffff81660721>] kmemleak_alloc+0x21/0x50 [<ffffffff81190aac>] __kmalloc_track_caller+0xec/0x2a0 [<ffffffff812fe1bb>] kvasprintf+0x5b/0x90 [<ffffffff812fe228>] kasprintf+0x38/0x40 [<ffffffff81041ec1>] xen_setup_timer+0x51/0xf0 [<ffffffff8166339f>] xen_cpu_up+0x5f/0x3e8 [<ffffffff8166bbf5>] _cpu_up+0xd1/0x14b [<ffffffff8166bd48>] cpu_up+0xd9/0xec [<ffffffff81ae6e4a>] smp_init+0x4b/0xa3 [<ffffffff81ac4981>] kernel_init_freeable+0xdb/0x1e6 [<ffffffff8165ce39>] kernel_init+0x9/0xf0 [<ffffffff8167edfc>] ret_from_fork+0x7c/0xb0 [<ffffffffffffffff>] 0xffffffffffffffff This patch fixes it by stashing away the 'name' in the per-cpu data structure and freeing it when offlining the CPU. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* | xen/time: Encapsulate the struct clock_event_device in another structure.Konrad Rzeszutek Wilk2013-06-101-5/+10
|/ | | | | | | | | We don't do any code movement. We just encapsulate the struct clock_event_device in a new structure which contains said structure and a pointer to a char *name. The 'name' will be used in 'xen/time: Don't leak interrupt name when offlining'. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* xen/time: Add default value of -1 for IRQ and check for that.Konrad Rzeszutek Wilk2013-04-161-2/+5
| | | | | | | | | If the timer interrupt has been de-init or is just now being initialized, the default value of -1 should be preset as interrupt line. Check for that and if something is odd WARN us. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* xen/time: Fix kasprintf splat when allocating timer%d IRQ line.Konrad Rzeszutek Wilk2013-04-161-1/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When we online the CPU, we get this splat: smpboot: Booting Node 0 Processor 1 APIC 0x2 installing Xen timer for CPU 1 BUG: sleeping function called from invalid context at /home/konrad/ssd/konrad/linux/mm/slab.c:3179 in_atomic(): 1, irqs_disabled(): 0, pid: 0, name: swapper/1 Pid: 0, comm: swapper/1 Not tainted 3.9.0-rc6upstream-00001-g3884fad #1 Call Trace: [<ffffffff810c1fea>] __might_sleep+0xda/0x100 [<ffffffff81194617>] __kmalloc_track_caller+0x1e7/0x2c0 [<ffffffff81303758>] ? kasprintf+0x38/0x40 [<ffffffff813036eb>] kvasprintf+0x5b/0x90 [<ffffffff81303758>] kasprintf+0x38/0x40 [<ffffffff81044510>] xen_setup_timer+0x30/0xb0 [<ffffffff810445af>] xen_hvm_setup_cpu_clockevents+0x1f/0x30 [<ffffffff81666d0a>] start_secondary+0x19c/0x1a8 The solution to that is use kasprintf in the CPU hotplug path that 'online's the CPU. That is, do it in in xen_hvm_cpu_notify, and remove the call to in xen_hvm_setup_cpu_clockevents. Unfortunatly the later is not a good idea as the bootup path does not use xen_hvm_cpu_notify so we would end up never allocating timer%d interrupt lines when booting. As such add the check for atomic() to continue. CC: stable@vger.kernel.org Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* Merge branch 'upstream/xen-settime' of ↵Linus Torvalds2011-11-061-1/+15
|\ | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen * 'upstream/xen-settime' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen: xen/dom0: set wallclock time in Xen xen: add dom0_op hypercall xen/acpi: Domain0 acpi parser related platform hypercall
| * xen/dom0: set wallclock time in XenJeremy Fitzhardinge2011-09-261-1/+15
| | | | | | | | Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
* | xen: use non-tracing preempt in xen_clocksource_read()Jeremy Fitzhardinge2011-08-241-2/+3
|/ | | | | | | | | | | | | | | | The tracing code used sched_clock() to get tracing timestamps, which ends up calling xen_clocksource_read(). xen_clocksource_read() must disable preemption, but if preemption tracing is enabled, this results in infinite recursion. I've only noticed this when boot-time tracing tests are enabled, but it seems like a generic bug. It looks like it would also affect kvm_clocksource_read(). Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Avi Kivity <avi@redhat.com> Cc: Marcelo Tosatti <mtosatti@redhat.com>
* Merge branch 'timers-clocksource-for-linus' of ↵Linus Torvalds2011-05-191-5/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-clocksource-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: clocksource: convert mips to generic i8253 clocksource clocksource: convert x86 to generic i8253 clocksource clocksource: convert footbridge to generic i8253 clocksource clocksource: add common i8253 PIT clocksource blackfin: convert to clocksource_register_hz mips: convert to clocksource_register_hz/khz sparc: convert to clocksource_register_hz/khz alpha: convert to clocksource_register_hz microblaze: convert to clocksource_register_hz/khz ia64: convert to clocksource_register_hz/khz x86: Convert remaining x86 clocksources to clocksource_register_hz/khz Make clocksource name const
| * Merge branch 'consolidate-clksrc-i8253' of ↵Thomas Gleixner2011-05-141-1/+3
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | master.kernel.org:~rmk/linux-2.6-arm into timers/clocksource Conflicts: arch/ia64/kernel/cyclone.c arch/mips/kernel/i8253.c arch/x86/kernel/i8253.c Reason: Resolve conflicts so further cleanups do not conflict further Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | x86: Convert remaining x86 clocksources to clocksource_register_hz/khzJohn Stultz2011-02-211-5/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This converts the remaining x86 clocksources to use clocksource_register_hz/khz. CC: jacob.jun.pan@intel.com CC: Glauber Costa <glommer@redhat.com> CC: Dimitri Sivanich <sivanich@sgi.com> CC: Rusty Russell <rusty@rustcorp.com.au> CC: Jeremy Fitzhardinge <jeremy@xensource.com> CC: Chris McDermott <lcm@us.ibm.com> CC: Thomas Gleixner <tglx@linutronix.de> Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> [xen] Signed-off-by: John Stultz <johnstul@us.ibm.com>
* | | arch/x86/xen/time: Cleanup code/data sections definitionsDaniel Kiper2011-05-191-4/+4
| |/ |/| | | | | | | | | | | | | Cleanup code/data sections definitions accordingly to include/linux/init.h. Signed-off-by: Daniel Kiper <dkiper@net-space.pl> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* | xen/timer: Missing IRQF_NO_SUSPEND in timer code broke suspend.Ian Campbell2011-03-031-1/+3
|/ | | | | | | | | | | The patches missed an indirect use of IRQF_NO_SUSPEND pulled in via IRQF_TIMER. The following patch fixes the issue. With this fixlet PV guest migration works just fine. I also booted the entire series as a dom0 kernel and it appeared fine. Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* Merge branch 'this_cpu_ops' into for-2.6.38Tejun Heo2010-12-171-0/+2
|\
| * x86/pvclock: Zero last_value on resumeJeremy Fitzhardinge2010-11-281-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | If the guest domain has been suspend/resumed or migrated, then the system clock backing the pvclock clocksource may revert to a smaller value (ie, can be non-monotonic across the migration/save-restore). Make sure we zero last_value in that case so that the domain continues to see clock updates. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>