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>
* master: (15791 commits)
Linux 3.9-rc1
btrfs/raid56: Add missing #include <linux/vmalloc.h>
fix compat_sys_rt_sigprocmask()
SUNRPC: One line comment fix
ext4: enable quotas before orphan cleanup
ext4: don't allow quota mount options when quota feature enabled
ext4: fix a warning from sparse check for ext4_dir_llseek
ext4: convert number of blocks to clusters properly
ext4: fix possible memory leak in ext4_remount()
jbd2: fix ERR_PTR dereference in jbd2__journal_start
metag: Provide dma_get_sgtable()
metag: prom.h: remove declaration of metag_dt_memblock_reserve()
metag: copy devicetree to non-init memory
metag: cleanup metag_ksyms.c includes
metag: move mm/init.c exports out of metag_ksyms.c
metag: move usercopy.c exports out of metag_ksyms.c
metag: move setup.c exports out of metag_ksyms.c
metag: move kick.c exports out of metag_ksyms.c
metag: move traps.c exports out of metag_ksyms.c
metag: move irq enable out of irqflags.h on SMP
...
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Conflicts:
arch/x86/kernel/kvmclock.c
This fixes boot lockups with "no-kvmclock", when the host is not
exposing this particular feature (QEMU: -cpu ...,-kvmclock) or when
the kvmclock initialization failed for whatever reason.
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
To match whats mapped via vsyscalls to userspace.
Reported-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
In short, it is illegal to call __pa() on an address holding
a percpu variable. This replaces those __pa() calls with
slow_virt_to_phys(). All of the cases in this patch are
in boot time (or CPU hotplug time at worst) code, so the
slow pagetable walking in slow_virt_to_phys() is not expected
to have a performance impact.
The times when this actually matters are pretty obscure
(certain 32-bit NUMA systems), but it _does_ happen. It is
important to keep KVM guests working on these systems because
the real hardware is getting harder and harder to find.
This bug manifested first by me seeing a plain hang at boot
after this message:
CPU 0 irqstacks, hard=f3018000 soft=f301a000
or, sometimes, it would actually make it out to the console:
[ 0.000000] BUG: unable to handle kernel paging request at ffffffff
I eventually traced it down to the KVM async pagefault code.
This can be worked around by disabling that code either at
compile-time, or on the kernel command-line.
The kvm async pagefault code was injecting page faults in
to the guest which the guest misinterpreted because its
"reason" was not being properly sent from the host.
The guest passes a physical address of an per-cpu async page
fault structure via an MSR to the host. Since __pa() is
broken on percpu data, the physical address it sent was
bascially bogus and the host went scribbling on random data.
The guest never saw the real reason for the page fault (it
was injected by the host), assumed that the kernel had taken
a _real_ page fault, and panic()'d. The behavior varied,
though, depending on what got corrupted by the bad write.
Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20130122212435.4905663F@kernel.stglabs.ibm.com
Acked-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Hook into generic pvclock vsyscall code, with the aim to
allow userspace to have visibility into pvclock data.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
We want to expose the pvclock shared memory areas, which
the hypervisor periodically updates, to userspace.
For a linear mapping from userspace, it is necessary that
entire page sized regions are used for array of pvclock
structures.
There is no such guarantee with per cpu areas, therefore move
to memblock_alloc based allocation.
Acked-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
CPU offline path calls the hrtimer interrupt handler with interrupts
disabled, without touching preempt_count, triggering this warning.
Remove the warning since it is supposed to be used from hrtimer
interrupt context only.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
check_and_clear_guest_paused does not need to be exported as it isn't used
by any modules, remove the export.
Signed-off-by: Eric B Munson <emunson@mgebm.net>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
When a host stops or suspends a VM it will set a flag to show this. The
watchdog will use these functions to determine if a softlockup is real, or the
result of a suspended VM.
Signed-off-by: Eric B Munson <emunson@mgebm.net>
asm-generic changes Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Upon resume from hibernation, CPU 0's hvclock area contains the old
values for system_time and tsc_timestamp. It is necessary for the
hypervisor to update these values with uptodate ones before the CPU uses
them.
Abstract TSC's save/restore sched_clock_state functions and use
restore_state to write to KVM_SYSTEM_TIME MSR, forcing an update.
Also move restore_sched_clock_state before __restore_processor_state,
since the later calls CONFIG_LOCK_STAT's lockstat_clock (also for TSC).
Thanks to Igor Mammedov for tracking it down.
Fixes suspend-to-disk with kvmclock.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
When kvm guest uses kvmclock, it may hang on vcpu hot-plug.
This is caused by an overflow in pvclock_get_nsec_offset,
u64 delta = tsc - shadow->tsc_timestamp;
which in turn is caused by an undefined values from percpu
hv_clock that hasn't been initialized yet.
Uninitialized clock on being booted cpu is accessed from
start_secondary
-> smp_callin
-> smp_store_cpu_info
-> identify_secondary_cpu
-> mtrr_ap_init
-> mtrr_restore
-> stop_machine_from_inactive_cpu
-> queue_stop_cpus_work
...
-> sched_clock
-> kvm_clock_read
which is well before x86_cpuinit.setup_percpu_clockev call in
start_secondary, where percpu clock is initialized.
This patch introduces a hook that allows to setup/initialize
per_cpu clock early and avoid overflow due to reading
- undefined values
- old values if cpu was offlined and then onlined again
Another possible early user of this clock source is ftrace that
accesses it to get timestamps for ring buffer entries. So if
mtrr_ap_init is moved from identify_secondary_cpu to past
x86_cpuinit.setup_percpu_clockev in start_secondary, ftrace
may cause the same overflow/hang on cpu hot-plug anyway.
More complete description of the problem:
https://lkml.org/lkml/2012/2/2/101
Credits to Marcelo Tosatti <mtosatti@redhat.com> for hook idea.
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Prevent tracing of preempt_disable() in get_cpu_var() in
kvm_clock_read(). When CONFIG_DEBUG_PREEMPT is enabled,
preempt_disable/enable() are traced and this causes the function_graph
tracer to go into an infinite recursion. By open coding the
preempt_disable() around the get_cpu_var(), we can use the notrace
version which prevents preempt_disable/enable() from being traced and
prevents the recursion.
Based on a similar patch for Xen from Jeremy Fitzhardinge.
Tested-by: Gleb Natapov <gleb@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Avi Kivity <avi@redhat.com>
This patch implements the kvm bits of the steal time infrastructure.
The most important part of it, is the steal time clock. It is an
continuous clock that shows the accumulated amount of steal time
since vcpu creation. It is supposed to survive cpu offlining/onlining.
[marcelo: fix build with CONFIG_KVM_GUEST=n]
Signed-off-by: Glauber Costa <glommer@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Tested-by: Eric B Munson <emunson@mgebm.net>
CC: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Avi Kivity <avi@redhat.com>
CC: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
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>
Async PF also needs to hook into smp_prepare_boot_cpu so move the hook
into generic code.
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Fix a hang during SMP kernel boot on KVM that showed up
after commit 489fb490db
(2.6.35) and 59aab522154a2f17b25335b63c1cf68a51fb6ae0
(2.6.34.1). The problem only occurs when
CONFIG_PRINTK_TIME is set.
KVM-Stable-Tag.
Signed-off-by: Arjan Koers <0h61vkll2ly8@xutrox.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
If the HV told us we can fully trust the TSC, skip any
correction
Signed-off-by: Glauber Costa <glommer@redhat.com>
Acked-by: Zachary Amsden <zamsden@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
We now added a new set of clock-related msrs in replacement of the old
ones. In theory, we could just try to use them and get a return value
indicating they do not exist, due to our use of kvm_write_msr_save.
However, kvm clock registration happens very early, and if we ever
try to write to a non-existant MSR, we raise a lethal #GP, since our
idt handlers are not in place yet.
So this patch tests for a cpuid feature exported by the host to
decide which set of msrs are supported.
Signed-off-by: Glauber Costa <glommer@redhat.com>
Acked-by: Zachary Amsden <zamsden@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
* 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (38 commits)
x86: Move get/set_wallclock to x86_platform_ops
x86: platform: Fix section annotations
x86: apic namespace cleanup
x86: Distangle ioapic and i8259
x86: Add Moorestown early detection
x86: Add hardware_subarch ID for Moorestown
x86: Add early platform detection
x86: Move tsc_init to late_time_init
x86: Move tsc_calibration to x86_init_ops
x86: Replace the now identical time_32/64.c by time.c
x86: time_32/64.c unify profile_pc
x86: Move calibrate_cpu to tsc.c
x86: Make timer setup and global variables the same in time_32/64.c
x86: Remove mca bus ifdef from timer interrupt
x86: Simplify timer_ack magic in time_32.c
x86: Prepare unification of time_32/64.c
x86: Remove do_timer hook
x86: Add timer_init to x86_init_ops
x86: Move percpu clockevents setup to x86_init_ops
x86: Move xen_post_allocator_init into xen_pagetable_setup_done
...
Fix up conflicts in arch/x86/include/asm/io_apic.h
get/set_wallclock() have already a set of platform dependent
implementations (default, EFI, paravirt). MRST will add another
variant.
Moving them to platform ops simplifies the existing code and minimizes
the effort to integrate new variants.
Signed-off-by: Feng Tang <feng.tang@intel.com>
LKML-Reference: <new-submission>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The use of __pa() to calculate the address of a C-visible symbol
is wrong, and can lead to unpredictable results. See arch/x86/include/asm/page.h
for details.
It should be replaced with __pa_symbol(), that does the correct math here,
by taking relocations into account. This ensures the correct wallclock data
structure physical address is passed to the hypervisor.
Cc: stable@kernel.org
Signed-off-by: Glauber Costa <glommer@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
TSC calibration is modified by the vmware hypervisor and paravirt by
separate means. Moorestown wants to add its own calibration routine as
well. So make calibrate_tsc a proper x86_init_ops function and
override it by paravirt or by the early setup of the vmware
hypervisor.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
paravirt overrides the setup of the default apic timers as per cpu
timers. Moorestown needs to override that as well.
Move it to x86_init_ops setup and create a separate x86_cpuinit struct
which holds the function for the secondary evtl. hotplugabble CPUs.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Pass clocksource pointer to the read() callback for clocksources. This
allows us to share the callback between multiple instances.
[hugh@veritas.com: fix powerpc build of clocksource pass clocksource mods]
[akpm@linux-foundation.org: cleanup]
Signed-off-by: Magnus Damm <damm@igel.co.jp>
Acked-by: John Stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Impact: cleanup
Make x86_quirks support more transparent. The highlevel
methods are now named:
extern void x86_quirk_pre_intr_init(void);
extern void x86_quirk_intr_init(void);
extern void x86_quirk_trap_init(void);
extern void x86_quirk_pre_time_init(void);
extern void x86_quirk_time_init(void);
This makes it clear that if some platform extension has to
do something here that it is considered ... weird, and is
discouraged.
Also remove arch_hooks.h and move it into setup.h (and other
header files where appropriate).
Signed-off-by: Ingo Molnar <mingo@elte.hu>
kvm_get_tsc_khz() currently returns the previously-calculated preset_lpj
value, but it is in loops-per-jiffy, not kHz. The current code works
correctly only when HZ=1000.
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Currently, we only set the KVM paravirt signature in case
of CONFIG_KVM_GUEST. However, it is possible to have it turned
off, while CONFIG_KVM_CLOCK is turned on. This is also a paravirt
case, and should be shown accordingly.
Signed-off-by: Glauber Costa <glommer@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
WARNING: arch/x86/kernel/built-in.o(.text+0x1722c): Section mismatch
in reference from the function kvm_setup_secondary_clock() to the
function .devinit.text:setup_secondary_APIC_clock()
The function kvm_setup_secondary_clock() references
the function __devinit setup_secondary_APIC_clock().
This is often because kvm_setup_secondary_clock lacks a __devinit
annotation or the annotation of setup_secondary_APIC_clock is wrong.
Signed-off-by: Md.Rakib H. Mullick <rakib.mullick@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Avi Kivity <avi@redhat.com>
We're currently facing timing problems in guests that do
calibration under heavy load, and then the load vanishes.
This means we'll have a much lower lpj than we actually should,
and delays end up taking less time than they should, which is a
nasty bug.
Solution is to pass on the lpj value from host to guest, and have it
preset.
Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
This patch makes the needlessly global kvm_smp_prepare_boot_cpu() static.
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Avi Kivity <avi@qumranet.com>
This patch updates the kvm host code to use the pvclock structs
and functions, thereby making it compatible with Xen.
The patch also fixes an initialization bug: on SMP systems the
per-cpu has two different locations early at boot and after CPU
bringup. kvmclock must take that in account when registering the
physical address within the host.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
Since the pv_apic_ops are only present if CONFIG_X86_LOCAL_APIC is compiled
in, kvmclock failed to build without this option. This patch fixes this.
Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
This patch writes 0 (actually, what really matters is that the
LSB is cleared) to the system time msr before shutting down
the machine for kexec.
Without it, we can have a random memory location being written
when the guest comes back
It overrides the functions shutdown, used in the path of kernel_kexec() (sys.c)
and crash_shutdown, used in the path of crash_kexec() (kexec.c)
Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
This is the guest part of kvm clock implementation
It does not do tsc-only timing, as tsc can have deltas
between cpus, and it did not seem worthy to me to keep
adjusting them.
We do use it, however, for fine-grained adjustment.
Other than that, time comes from the host.
[randy dunlap: add missing include]
[randy dunlap: disallow on Voyager or Visual WS]
Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
