linux-toradex.git/arch/x86/include/asm/pvclock.h, branch v4.0.5

x86: kvm: Revert "remove sched notifier for cross-cpu migrations"

2015-05-06T20:03:36+00:00

commit 0a4e6be9ca17c54817cf814b4b5aa60478c6df27 upstream.

The following point:

    2. per-CPU pvclock time info is updated if the
       underlying CPU changes.

Is not true anymore since "KVM: x86: update pvclock area conditionally,
on cpu migration".

Add task migration notification back.

Problem noticed by Andy Lutomirski.

Signed-off-by: Marcelo Tosatti 
Signed-off-by: Greg Kroah-Hartman

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: 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: add note about rdtsc barriers

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

As noted by Gleb, not advertising SSE2 support implies
no RDTSC barriers.

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

KVM: Fix instruction size issue in pvclock scaling

2011-08-30T11:42:30+00:00

Commit de2d1a524e94 ("KVM: Fix register corruption in pvclock_scale_delta")
introduced a mul instruction that may have only a memory operand; the
assembler therefore cannot select the correct size:

   pvclock.s:229: Error: no instruction mnemonic suffix given and no register
operands; can't size instruction

In this example the assembler is:

         #APP
         mul -48(%rbp) ; shrd $32, %rdx, %rax
         #NO_APP

A simple solution is to use mulq.

Signed-off-by: Duncan Sands 
Signed-off-by: Avi Kivity

KVM: Fix register corruption in pvclock_scale_delta

2011-06-19T16:23:14+00:00

The 128-bit multiply in pvclock.h was missing an output constraint for
EDX which caused a register corruption to appear.  Thanks to Ulrich for
diagnosing the EDX corruption and Avi for providing this fix.

Signed-off-by: Zachary Amsden 
Signed-off-by: Avi Kivity

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