KVM: PPC: Book3S PR: Add C function wrapper for _kvmppc_save/restore_tm()

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>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

3 files changed, 101 insertions, 5 deletions

diff --git a/arch/powerpc/include/asm/asm-prototypes.h b/arch/powerpc/include/asm/asm-prototypes.h
index dfdcb2374c28..5da683bebc7f 100644
--- a/arch/powerpc/include/asm/asm-prototypes.h
+++ b/arch/powerpc/include/asm/asm-prototypes.h
@@ -141,7 +141,13 @@ unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip);
 void pnv_power9_force_smt4_catch(void);
 void pnv_power9_force_smt4_release(void);
 
+/* 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 75e3bbf8c957..af631d8303f6 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -3138,12 +3138,12 @@ END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
 kvmppc_save_tm_hv:
         /* See if we need to handle fake suspend mode */
 BEGIN_FTR_SECTION
-        b       kvmppc_save_tm
+        b       __kvmppc_save_tm
 END_FTR_SECTION_IFCLR(CPU_FTR_P9_TM_HV_ASSIST)
 
         lbz     r0, HSTATE_FAKE_SUSPEND(r13) /* Were we fake suspended? */
         cmpwi   r0, 0
-        beq     kvmppc_save_tm
+        beq     __kvmppc_save_tm
 
         /* The following code handles the fake_suspend = 1 case */
         mflr    r0
@@ -3228,7 +3228,7 @@ kvmppc_restore_tm_hv:
          * fake-suspend mode, or emulate a TM rollback.
          */
 BEGIN_FTR_SECTION
-        b       kvmppc_restore_tm
+        b       __kvmppc_restore_tm
 END_FTR_SECTION_IFCLR(CPU_FTR_P9_TM_HV_ASSIST)
         mflr    r0
         std     r0, PPC_LR_STKOFF(r1)
diff --git a/arch/powerpc/kvm/tm.S b/arch/powerpc/kvm/tm.S
index 2760d7acd371..4a68dd4050a4 100644
--- a/arch/powerpc/kvm/tm.S
+++ b/arch/powerpc/kvm/tm.S
@@ -33,7 +33,7 @@
  * 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)
 
@@ -157,6 +157,52 @@ END_FTR_SECTION_IFSET(CPU_FTR_P9_TM_HV_ASSIST)
         blr
 
 /*
+ * _kvmppc_save_tm_pr() 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.
@@ -166,7 +212,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_P9_TM_HV_ASSIST)
  * 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)
 
@@ -279,4 +325,48 @@ _GLOBAL(kvmppc_restore_tm)
         ld      r0, PPC_LR_STKOFF(r1)
         mtlr    r0
         blr
+
+/*
+ * _kvmppc_restore_tm_pr() 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 /* CONFIG_PPC_TRANSACTIONAL_MEM */