[v2,07/30] KVM: PPC: Book3S PR: add C function wrapper for _kvmppc_save/restore_tm()

Message ID 1519753057-11059-8-git-send-email-wei.guo.simon@gmail.com
State Changes Requested
Headers show
Series
  • KVM: PPC: Book3S PR: Transaction memory support on PR KVM
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Commit Message

Simon Guo Feb. 27, 2018, 5:37 p.m.
From: Simon Guo <wei.guo.simon@gmail.com>

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@gmail.com>
---
 arch/powerpc/include/asm/asm-prototypes.h |  6 ++
 arch/powerpc/kvm/book3s_hv_rmhandlers.S   |  8 +--
 arch/powerpc/kvm/tm.S                     | 95 ++++++++++++++++++++++++++++++-
 3 files changed, 103 insertions(+), 6 deletions(-)

Comments

Paul Mackerras May 15, 2018, 6:05 a.m. | #1
On Wed, Feb 28, 2018 at 01:37:14AM +0800, wei.guo.simon@gmail.com wrote:
> From: Simon Guo <wei.guo.simon@gmail.com>
> 
> 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@gmail.com>

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.

> +	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?

>  
>  	/* 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.

> +	mflr	r5
> +	std	r5, PPC_LR_STKOFF(r1)
> +	stdu    r1, -SWITCH_FRAME_SIZE(r1)
> +	SAVE_NVGPRS(r1)
> +
> +	/* save MSR to avoid TM/math bits change */
> +	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_restore_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_restore_tm_pr);
>  #endif
> -- 
> 1.8.3.1

Paul.
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Simon Guo May 15, 2018, 12:41 p.m. | #2
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@gmail.com wrote:
> > From: Simon Guo <wei.guo.simon@gmail.com>
> > 
> > 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@gmail.com>
> 
> 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
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Patch

diff --git a/arch/powerpc/include/asm/asm-prototypes.h b/arch/powerpc/include/asm/asm-prototypes.h
index 002abfc..b0ccd91 100644
--- a/arch/powerpc/include/asm/asm-prototypes.h
+++ b/arch/powerpc/include/asm/asm-prototypes.h
@@ -126,7 +126,13 @@  unsigned long __init prom_init(unsigned long r3, unsigned long r4,
 void _mcount(void);
 unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip);
 
+/* Transaction memory related */
 void tm_enable(void);
 void tm_disable(void);
 void tm_abort(uint8_t cause);
+
+struct kvm_vcpu;
+void _kvmppc_restore_tm_pr(struct kvm_vcpu *vcpu, u64 guest_msr);
+void _kvmppc_save_tm_pr(struct kvm_vcpu *vcpu, u64 guest_msr);
+
 #endif /* _ASM_POWERPC_ASM_PROTOTYPES_H */
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index df13cea..4b59424 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -790,7 +790,7 @@  BEGIN_FTR_SECTION
 	 */
 	mr      r3, r4
 	ld      r4, VCPU_MSR(r3)
-	bl	kvmppc_restore_tm
+	bl	__kvmppc_restore_tm
 	ld	r4, HSTATE_KVM_VCPU(r13)
 END_FTR_SECTION_IFSET(CPU_FTR_TM)
 #endif
@@ -1735,7 +1735,7 @@  BEGIN_FTR_SECTION
 	 */
 	mr      r3, r9
 	ld      r4, VCPU_MSR(r3)
-	bl	kvmppc_save_tm
+	bl	__kvmppc_save_tm
 	ld	r9, HSTATE_KVM_VCPU(r13)
 END_FTR_SECTION_IFSET(CPU_FTR_TM)
 #endif
@@ -2596,7 +2596,7 @@  BEGIN_FTR_SECTION
 	 */
 	ld      r3, HSTATE_KVM_VCPU(r13)
 	ld      r4, VCPU_MSR(r3)
-	bl	kvmppc_save_tm
+	bl	__kvmppc_save_tm
 END_FTR_SECTION_IFSET(CPU_FTR_TM)
 #endif
 
@@ -2710,7 +2710,7 @@  BEGIN_FTR_SECTION
 	 */
 	mr      r3, r4
 	ld      r4, VCPU_MSR(r3)
-	bl	kvmppc_restore_tm
+	bl	__kvmppc_restore_tm
 	ld	r4, HSTATE_KVM_VCPU(r13)
 END_FTR_SECTION_IFSET(CPU_FTR_TM)
 #endif
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)
+	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)
 
 	/* 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)
+	mflr	r5
+	std	r5, PPC_LR_STKOFF(r1)
+	stdu    r1, -SWITCH_FRAME_SIZE(r1)
+	SAVE_NVGPRS(r1)
+
+	/* save MSR to avoid TM/math bits change */
+	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_restore_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_restore_tm_pr);
 #endif