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