linux.git/arch/x86/kernel/pvclock.c, branch v3.15

hung_task: add method to reset detector

2013-11-06T07:49:02+00:00

In certain occasions it is possible for a hung task detector
positive to be false: continuation from a paused VM, for example.

Add a method to reset detection, similar as is done
with other kernel watchdogs.

Acked-by: Don Zickus 
Acked-by: Paolo Bonzini 
Signed-off-by: Marcelo Tosatti 
Signed-off-by: Gleb Natapov

pvclock: detect watchdog reset at pvclock read

2013-11-06T07:48:43+00:00

Implement reset of kernel watchdogs at pvclock read time. This avoids
adding special code to every watchdog.

This is possible for watchdogs which measure time based on sched_clock() or
ktime_get() variants.

Suggested by Don Zickus.

Acked-by: Don Zickus 
Acked-by: Paolo Bonzini 
Signed-off-by: Marcelo Tosatti 
Signed-off-by: Gleb Natapov

remove sched notifier for cross-cpu migrations

2013-07-18T10:29:30+00:00

Linux as a guest on KVM hypervisor, the only user of the pvclock
vsyscall interface, does not require notification on task migration
because:

1. cpu ID number maps 1:1 to per-CPU pvclock time info.
2. per-CPU pvclock time info is updated if the
   underlying CPU changes.
3. that version is increased whenever underlying CPU
   changes.

Which is sufficient to guarantee nanoseconds counter
is calculated properly.

Signed-off-by: Marcelo Tosatti 
Acked-by: Peter Zijlstra 
Signed-off-by: Gleb Natapov

x86/kvm: Fix pvclock vsyscall fixmap

2013-02-28T06:50:11+00:00

The physical memory fixmapped for the pvclock clock_gettime vsyscall
was allocated, and thus is not a kernel symbol. __pa() is the proper
method to use in this case.

Fixes the crash below when booting a next-20130204+ smp guest on a
3.8-rc5+ KVM host.

[    0.666410] udevd[97]: starting version 175
[    0.674043] udevd[97]: udevd:[97]: segfault at ffffffffff5fd020
     ip 00007fff069e277f sp 00007fff068c9ef8 error d

Acked-by: Marcelo Tosatti 
Signed-off-by: Peter Hurley 
Signed-off-by: Gleb Natapov

x86: pvclock: generic pvclock vsyscall initialization

2012-11-28T01:29:09+00:00

Originally from Jeremy Fitzhardinge.

Introduce generic, non hypervisor specific, pvclock initialization
routines.

Signed-off-by: Marcelo Tosatti

x86: pvclock: introduce helper to read flags

2012-11-28T01:29:08+00:00

Acked-by: Glauber Costa 
Signed-off-by: Marcelo Tosatti

x86: pvclock: create helper for pvclock data retrieval

2012-11-28T01:29:07+00:00

Originally from Jeremy Fitzhardinge.

So code can be reused.

Acked-by: Glauber Costa 
Signed-off-by: Marcelo Tosatti

x86: pvclock: remove pvclock_shadow_time

2012-11-28T01:29:06+00:00

Originally from Jeremy Fitzhardinge.

We can copy the information directly from "struct pvclock_vcpu_time_info",
remove pvclock_shadow_time.

Reviewed-by: Glauber Costa 
Signed-off-by: Marcelo Tosatti

x86: pvclock: make sure rdtsc doesnt speculate out of region

2012-11-28T01:29:06+00:00

Originally from Jeremy Fitzhardinge.

pvclock_get_time_values, which contains the memory barriers
will be removed by next patch.

Signed-off-by: Marcelo Tosatti

x86/pvclock: Zero last_value on resume

2010-11-28T08:33:20+00:00

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 
Signed-off-by: Ingo Molnar