On Tue, May 15, 2018 at 04:05:48PM +1000, Paul Mackerras wrote: > On Wed, Feb 28, 2018 at 01:37:14AM +0800, wei.guo.simon@xxxxxxxxx wrote: > > From: Simon Guo <wei.guo.simon@xxxxxxxxx> > > > > Currently _kvmppc_save/restore_tm() APIs can only be invoked from > > assembly function. This patch adds C function wrappers for them so > > that they can be safely called from C function. > > > > Signed-off-by: Simon Guo <wei.guo.simon@xxxxxxxxx> > > Some relatively minor comments below: > > > diff --git a/arch/powerpc/kvm/tm.S b/arch/powerpc/kvm/tm.S > > index 2d6fe5b..269dd11 100644 > > --- a/arch/powerpc/kvm/tm.S > > +++ b/arch/powerpc/kvm/tm.S > > @@ -35,7 +35,7 @@ > > * This can modify all checkpointed registers, but > > * restores r1, r2 before exit. > > */ > > -_GLOBAL(kvmppc_save_tm) > > +_GLOBAL(__kvmppc_save_tm) > > mflr r0 > > std r0, PPC_LR_STKOFF(r1) > > > > @@ -149,6 +149,52 @@ _GLOBAL(kvmppc_save_tm) > > blr > > > > /* > > + * _kvmppc_save_tm() is a wrapper around __kvmppc_save_tm(), so that it can > > + * be invoked from C function by PR KVM only. > > + */ > > +_GLOBAL(_kvmppc_save_tm_pr) > > The comment doesn't match the actual function name. I will correct that. Thanks for point it out. > > > + mflr r5 > > + std r5, PPC_LR_STKOFF(r1) > > + stdu r1, -SWITCH_FRAME_SIZE(r1) > > + SAVE_NVGPRS(r1) > > + > > + /* save MSR since TM/math bits might be impacted > > + * by __kvmppc_save_tm(). > > + */ > > + mfmsr r5 > > + SAVE_GPR(5, r1) > > + > > + /* also save DSCR/CR so that it can be recovered later */ > > + mfspr r6, SPRN_DSCR > > + SAVE_GPR(6, r1) > > + > > + mfcr r7 > > + stw r7, _CCR(r1) > > + > > + bl __kvmppc_save_tm > > + > > + ld r7, _CCR(r1) > > + mtcr r7 > > + > > + REST_GPR(6, r1) > > + mtspr SPRN_DSCR, r6 > > + > > + /* need preserve current MSR's MSR_TS bits */ > > + REST_GPR(5, r1) > > + mfmsr r6 > > + rldicl r6, r6, 64 - MSR_TS_S_LG, 62 > > + rldimi r5, r6, MSR_TS_S_LG, 63 - MSR_TS_T_LG > > + mtmsrd r5 > > + > > + REST_NVGPRS(r1) > > + addi r1, r1, SWITCH_FRAME_SIZE > > + ld r5, PPC_LR_STKOFF(r1) > > + mtlr r5 > > + blr > > + > > +EXPORT_SYMBOL_GPL(_kvmppc_save_tm_pr); > > + > > +/* > > * Restore transactional state and TM-related registers. > > * Called with: > > * - r3 pointing to the vcpu struct. > > @@ -158,7 +204,7 @@ _GLOBAL(kvmppc_save_tm) > > * This potentially modifies all checkpointed registers. > > * It restores r1, r2 from the PACA. > > */ > > -_GLOBAL(kvmppc_restore_tm) > > +_GLOBAL(__kvmppc_restore_tm) > > mflr r0 > > std r0, PPC_LR_STKOFF(r1) > > > > @@ -186,6 +232,7 @@ _GLOBAL(kvmppc_restore_tm) > > rldicl. r5, r5, 64 - MSR_TS_S_LG, 62 > > beqlr /* TM not active in guest */ > > std r1, HSTATE_SCRATCH2(r13) > > + std r3, HSTATE_SCRATCH1(r13) > > Why do we need to save r3 here and restore it below? I think it is a legacy change when I did TM save/restore on each trap from guest to host. It can be removed now. > > > > > /* Make sure the failure summary is set, otherwise we'll program check > > * when we trechkpt. It's possible that this might have been not set > > @@ -262,6 +309,7 @@ _GLOBAL(kvmppc_restore_tm) > > ld r29, HSTATE_DSCR(r13) > > mtspr SPRN_DSCR, r29 > > #endif > > + ld r3, HSTATE_SCRATCH1(r13) > > ld r1, HSTATE_SCRATCH2(r13) > > ld r2, PACATMSCRATCH(r13) > > > > @@ -273,4 +321,47 @@ _GLOBAL(kvmppc_restore_tm) > > mtlr r0 > > blr > > > > +/* > > + * _kvmppc_restore_tm() is a wrapper around __kvmppc_restore_tm(), so that it > > + * can be invoked from C function by PR KVM only. > > + */ > > +_GLOBAL(_kvmppc_restore_tm_pr) > > Again, comment doesn't match the actual function name. I will correct that. Thanks, - Simon
