On Thu, Jun 09, 2016 at 02:47:54PM +0200, Paolo Bonzini wrote:
> On 09/06/2016 14:43, Roman Kagan wrote:
> > On Thu, Jun 09, 2016 at 01:23:23PM +0200, Paolo Bonzini wrote:
> >> The version field in struct pvclock_vcpu_time_info basically implements
> >> a seqcount. Wrap it with the usual read_begin and read_retry functions,
> >> and use these APIs instead of peppering the code with smp_rmb()s.
> >> While at it, change it to the more pedantically correct virt_rmb().
> >>
> >> With this change, __pvclock_read_cycles can be simplified noticeably.
> >>
> >> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> >> ---
> >> arch/x86/entry/vdso/vclock_gettime.c | 25 +++++------------------
> >> arch/x86/include/asm/pvclock.h | 39 +++++++++++++++++++++---------------
> >> arch/x86/kernel/pvclock.c | 17 ++++++----------
> >> 3 files changed, 34 insertions(+), 47 deletions(-)
> > [...]
> >> --- a/arch/x86/include/asm/pvclock.h
> >> +++ b/arch/x86/include/asm/pvclock.h
> > [...]
> >> @@ -69,23 +87,12 @@ static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift)
> >> }
> >>
> >> static __always_inline
> >> -unsigned __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src,
> >> - cycle_t *cycles, u8 *flags)
> >> +cycle_t __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src)
> >> {
> >> - unsigned version;
> >> - cycle_t offset;
> >> - u64 delta;
> >> -
> >> - version = src->version;
> >> - /* Make the latest version visible */
> >> - smp_rmb();
> >
> > This is on top of Minfei's patch, right? It isn't in Linus' tree yet so
> > I wonder if it makes sense to merge the two patches into one.
> >
> > Will you post it to stable, too?
>
> Not this one, because Minfei's patch is enough to fix the bug, but I do
Has it landed in any public tree? I'm unable to find any. There
appears to be another version of the patch on the list, so I'm confused.
Roman.
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
