| Message ID | 20170825043036.18236-4-npiggin@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 72b0d51d973beab5a06c97279b61a0a58ccf33c8 |
| Headers | show |
On Fri, Aug 25, 2017 at 02:30:35PM +1000, Nicholas Piggin wrote: > The hardware can execute stop in any context, and KVM does not > require real mode because siblings do not share MMU state. This > saves a switch to real-mode when going idle. > > Acked-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> > Signed-off-by: Nicholas Piggin <npiggin@gmail.com> > --- > arch/powerpc/kernel/idle_book3s.S | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S > index 14e97f442167..32d65ee323a0 100644 > --- a/arch/powerpc/kernel/idle_book3s.S > +++ b/arch/powerpc/kernel/idle_book3s.S > @@ -195,7 +195,16 @@ pnv_powersave_common: > std r5,_CCR(r1) > std r1,PACAR1(r13) > > +BEGIN_FTR_SECTION > + /* > + * POWER9 does not require real mode to stop, and presently does not > + * set hwthread_state for KVM (threads don't share MMU context), so > + * we can remain in virtual mode for this. > + */ > + bctr > +END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300) > /* > + * POWER8 ... and POWER7 too. Since that's just a comment, Reviewed-by: Paul Mackerras <paulus@ozlabs.org>
On Fri, 2017-08-25 at 04:30:35 UTC, Nicholas Piggin wrote: > The hardware can execute stop in any context, and KVM does not > require real mode because siblings do not share MMU state. This > saves a switch to real-mode when going idle. > > Acked-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> > Signed-off-by: Nicholas Piggin <npiggin@gmail.com> > Reviewed-by: Paul Mackerras <paulus@ozlabs.org> Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/72b0d51d973beab5a06c97279b61a0 cheers
diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S index 14e97f442167..32d65ee323a0 100644 --- a/arch/powerpc/kernel/idle_book3s.S +++ b/arch/powerpc/kernel/idle_book3s.S @@ -195,7 +195,16 @@ pnv_powersave_common: std r5,_CCR(r1) std r1,PACAR1(r13) +BEGIN_FTR_SECTION + /* + * POWER9 does not require real mode to stop, and presently does not + * set hwthread_state for KVM (threads don't share MMU context), so + * we can remain in virtual mode for this. + */ + bctr +END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300) /* + * POWER8 * Go to real mode to do the nap, as required by the architecture. * Also, we need to be in real mode before setting hwthread_state, * because as soon as we do that, another thread can switch