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KVM: PPC: Book3S: Rework TM save/restore code and make it C-callable 

This adds a parameter to __kvmppc_save_tm and __kvmppc_restore_tm
which allows the caller to indicate whether it wants the nonvolatile
register state to be preserved across the call, as required by the C
calling conventions.  This parameter being non-zero also causes the
MSR bits that enable TM, FP, VMX and VSX to be preserved.  The
condition register and DSCR are now always preserved.

With this, kvmppc_save_tm_hv and kvmppc_restore_tm_hv can be called
from C code provided the 3rd parameter is non-zero.  So that these
functions can be called from modules, they now include code to set
the TOC pointer (r2) on entry, as they can call other built-in C
functions which will assume the TOC to have been set.

Also, the fake suspend code in kvmppc_save_tm_hv is modified here to
assume that treclaim in fake-suspend state does not modify any registers,
which is the case on POWER9.  This enables the code to be simplified
quite a bit.

_kvmppc_save_tm_pr and _kvmppc_restore_tm_pr become much simpler with
this change, since they now only need to save and restore TAR and pass
1 for the 3rd argument to __kvmppc_{save,restore}_tm.

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Paul Mackerras 2018-10-08 16:30:53 +11:00 committed by Michael Ellerman
parent df709a296e
commit 7854f7545b
3 changed files with 170 additions and 141 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
arch/powerpc/include/asm/asm-prototypes.h
View File

@ -150,6 +150,16 @@ extern s32 patch__memset_nocache, patch__memcpy_nocache;
extern long flush_count_cache;
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
void kvmppc_save_tm_hv(struct kvm_vcpu *vcpu, u64 msr, bool preserve_nv);
void kvmppc_restore_tm_hv(struct kvm_vcpu *vcpu, u64 msr, bool preserve_nv);
#else
static inline void kvmppc_save_tm_hv(struct kvm_vcpu *vcpu, u64 msr,
bool preserve_nv) { }
static inline void kvmppc_restore_tm_hv(struct kvm_vcpu *vcpu, u64 msr,
bool preserve_nv) { }
#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
void kvmhv_save_host_pmu(void);
void kvmhv_load_host_pmu(void);
void kvmhv_save_guest_pmu(struct kvm_vcpu *vcpu, bool pmu_in_use);

49
arch/powerpc/kvm/book3s_hv_rmhandlers.S
View File

@ -759,11 +759,13 @@ BEGIN_FTR_SECTION
b 91f
END_FTR_SECTION(CPU_FTR_TM | CPU_FTR_P9_TM_HV_ASSIST, 0)
/*
* NOTE THAT THIS TRASHES ALL NON-VOLATILE REGISTERS INCLUDING CR
* NOTE THAT THIS TRASHES ALL NON-VOLATILE REGISTERS (but not CR)
*/
mr r3, r4
ld r4, VCPU_MSR(r3)
li r5, 0 /* don't preserve non-vol regs */
bl kvmppc_restore_tm_hv
nop
ld r4, HSTATE_KVM_VCPU(r13)
91:
#endif
@ -1603,11 +1605,13 @@ BEGIN_FTR_SECTION
b 91f
END_FTR_SECTION(CPU_FTR_TM | CPU_FTR_P9_TM_HV_ASSIST, 0)
/*
* NOTE THAT THIS TRASHES ALL NON-VOLATILE REGISTERS INCLUDING CR
* NOTE THAT THIS TRASHES ALL NON-VOLATILE REGISTERS (but not CR)
*/
mr r3, r9
ld r4, VCPU_MSR(r3)
li r5, 0 /* don't preserve non-vol regs */
bl kvmppc_save_tm_hv
nop
ld r9, HSTATE_KVM_VCPU(r13)
91:
#endif
@ -2486,11 +2490,13 @@ BEGIN_FTR_SECTION
b 91f
END_FTR_SECTION(CPU_FTR_TM | CPU_FTR_P9_TM_HV_ASSIST, 0)
/*
* NOTE THAT THIS TRASHES ALL NON-VOLATILE REGISTERS INCLUDING CR
* NOTE THAT THIS TRASHES ALL NON-VOLATILE REGISTERS (but not CR)
*/
ld r3, HSTATE_KVM_VCPU(r13)
ld r4, VCPU_MSR(r3)
li r5, 0 /* don't preserve non-vol regs */
bl kvmppc_save_tm_hv
nop
91:
#endif
@ -2606,11 +2612,13 @@ BEGIN_FTR_SECTION
b 91f
END_FTR_SECTION(CPU_FTR_TM | CPU_FTR_P9_TM_HV_ASSIST, 0)
/*
* NOTE THAT THIS TRASHES ALL NON-VOLATILE REGISTERS INCLUDING CR
* NOTE THAT THIS TRASHES ALL NON-VOLATILE REGISTERS (but not CR)
*/
mr r3, r4
ld r4, VCPU_MSR(r3)
li r5, 0 /* don't preserve non-vol regs */
bl kvmppc_restore_tm_hv
nop
ld r4, HSTATE_KVM_VCPU(r13)
91:
#endif
@ -2943,10 +2951,12 @@ END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
* Save transactional state and TM-related registers.
* Called with r3 pointing to the vcpu struct and r4 containing
* the guest MSR value.
* This can modify all checkpointed registers, but
* r5 is non-zero iff non-volatile register state needs to be maintained.
* If r5 == 0, this can modify all checkpointed registers, but
* restores r1 and r2 before exit.
*/
kvmppc_save_tm_hv:
_GLOBAL_TOC(kvmppc_save_tm_hv)
EXPORT_SYMBOL_GPL(kvmppc_save_tm_hv)
/* See if we need to handle fake suspend mode */
BEGIN_FTR_SECTION
b __kvmppc_save_tm
@ -2974,12 +2984,6 @@ BEGIN_FTR_SECTION
END_FTR_SECTION_IFSET(CPU_FTR_P9_TM_XER_SO_BUG)
nop
std r1, HSTATE_HOST_R1(r13)
/* Clear the MSR RI since r1, r13 may be foobar. */
li r5, 0
mtmsrd r5, 1
/* We have to treclaim here because that's the only way to do S->N */
li r3, TM_CAUSE_KVM_RESCHED
TRECLAIM(R3)
@ -2988,22 +2992,13 @@ END_FTR_SECTION_IFSET(CPU_FTR_P9_TM_XER_SO_BUG)
* We were in fake suspend, so we are not going to save the
* register state as the guest checkpointed state (since
* we already have it), therefore we can now use any volatile GPR.
* In fact treclaim in fake suspend state doesn't modify
* any registers.
*/
/* Reload PACA pointer, stack pointer and TOC. */
GET_PACA(r13)
ld r1, HSTATE_HOST_R1(r13)
ld r2, PACATOC(r13)
/* Set MSR RI now we have r1 and r13 back. */
li r5, MSR_RI
mtmsrd r5, 1
HMT_MEDIUM
ld r6, HSTATE_DSCR(r13)
mtspr SPRN_DSCR, r6
BEGIN_FTR_SECTION_NESTED(96)
BEGIN_FTR_SECTION
bl pnv_power9_force_smt4_release
END_FTR_SECTION_NESTED(CPU_FTR_P9_TM_XER_SO_BUG, CPU_FTR_P9_TM_XER_SO_BUG, 96)
END_FTR_SECTION_IFSET(CPU_FTR_P9_TM_XER_SO_BUG)
nop
4:
@ -3029,10 +3024,12 @@ END_FTR_SECTION_NESTED(CPU_FTR_P9_TM_XER_SO_BUG, CPU_FTR_P9_TM_XER_SO_BUG, 96)
* Restore transactional state and TM-related registers.
* Called with r3 pointing to the vcpu struct
* and r4 containing the guest MSR value.
* r5 is non-zero iff non-volatile register state needs to be maintained.
* This potentially modifies all checkpointed registers.
* It restores r1 and r2 from the PACA.
*/
kvmppc_restore_tm_hv:
_GLOBAL_TOC(kvmppc_restore_tm_hv)
EXPORT_SYMBOL_GPL(kvmppc_restore_tm_hv)
/*
* If we are doing TM emulation for the guest on a POWER9 DD2,
* then we don't actually do a trechkpt -- we either set up

252
arch/powerpc/kvm/tm.S
View File

@ -28,17 +28,25 @@
* Save transactional state and TM-related registers.
* Called with:
* - r3 pointing to the vcpu struct
* - r4 points to the MSR with current TS bits:
* - r4 containing the MSR with current TS bits:
* (For HV KVM, it is VCPU_MSR ; For PR KVM, it is host MSR).
* This can modify all checkpointed registers, but
* restores r1, r2 before exit.
* - r5 containing a flag indicating that non-volatile registers
* must be preserved.
* If r5 == 0, this can modify all checkpointed registers, but
* restores r1, r2 before exit. If r5 != 0, this restores the
* MSR TM/FP/VEC/VSX bits to their state on entry.
*/
_GLOBAL(__kvmppc_save_tm)
mflr r0
std r0, PPC_LR_STKOFF(r1)
stdu r1, -SWITCH_FRAME_SIZE(r1)
mr r9, r3
cmpdi cr7, r5, 0
/* Turn on TM. */
mfmsr r8
mr r10, r8
li r0, 1
rldimi r8, r0, MSR_TM_LG, 63-MSR_TM_LG
ori r8, r8, MSR_FP
@ -51,6 +59,27 @@ _GLOBAL(__kvmppc_save_tm)
std r1, HSTATE_SCRATCH2(r13)
std r3, HSTATE_SCRATCH1(r13)
/* Save CR on the stack - even if r5 == 0 we need to get cr7 back. */
mfcr r6
SAVE_GPR(6, r1)
/* Save DSCR so we can restore it to avoid running with user value */
mfspr r7, SPRN_DSCR
SAVE_GPR(7, r1)
/*
* We are going to do treclaim., which will modify all checkpointed
* registers. Save the non-volatile registers on the stack if
* preservation of non-volatile state has been requested.
*/
beq cr7, 3f
SAVE_NVGPRS(r1)
/* MSR[TS] will be 0 (non-transactional) once we do treclaim. */
li r0, 0
rldimi r10, r0, MSR_TS_S_LG, 63 - MSR_TS_T_LG
SAVE_GPR(10, r1) /* final MSR value */
3:
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
BEGIN_FTR_SECTION
/* Emulation of the treclaim instruction needs TEXASR before treclaim */
@ -74,22 +103,25 @@ END_FTR_SECTION_IFSET(CPU_FTR_P9_TM_HV_ASSIST)
std r9, PACATMSCRATCH(r13)
ld r9, HSTATE_SCRATCH1(r13)
/* Get a few more GPRs free. */
std r29, VCPU_GPRS_TM(29)(r9)
std r30, VCPU_GPRS_TM(30)(r9)
std r31, VCPU_GPRS_TM(31)(r9)
/* Save away PPR and DSCR soon so don't run with user values. */
mfspr r31, SPRN_PPR
/* Save away PPR soon so we don't run with user value. */
std r0, VCPU_GPRS_TM(0)(r9)
mfspr r0, SPRN_PPR
HMT_MEDIUM
mfspr r30, SPRN_DSCR
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
ld r29, HSTATE_DSCR(r13)
mtspr SPRN_DSCR, r29
#endif
/* Save all but r9, r13 & r29-r31 */
reg = 0
/* Reload stack pointer. */
std r1, VCPU_GPRS_TM(1)(r9)
ld r1, HSTATE_SCRATCH2(r13)
/* Set MSR RI now we have r1 and r13 back. */
std r2, VCPU_GPRS_TM(2)(r9)
li r2, MSR_RI
mtmsrd r2, 1
/* Reload TOC pointer. */
ld r2, PACATOC(r13)
/* Save all but r0-r2, r9 & r13 */
reg = 3
.rept 29
.if (reg != 9) && (reg != 13)
std reg, VCPU_GPRS_TM(reg)(r9)
@ -103,33 +135,29 @@ END_FTR_SECTION_IFSET(CPU_FTR_P9_TM_HV_ASSIST)
ld r4, PACATMSCRATCH(r13)
std r4, VCPU_GPRS_TM(9)(r9)
/* Reload stack pointer and TOC. */
ld r1, HSTATE_SCRATCH2(r13)
ld r2, PACATOC(r13)
/* Set MSR RI now we have r1 and r13 back. */
li r5, MSR_RI
mtmsrd r5, 1
/* Save away checkpinted SPRs. */
std r31, VCPU_PPR_TM(r9)
std r30, VCPU_DSCR_TM(r9)
mflr r5
/* Restore host DSCR and CR values, after saving guest values */
mfcr r6
mfspr r7, SPRN_DSCR
stw r6, VCPU_CR_TM(r9)
std r7, VCPU_DSCR_TM(r9)
REST_GPR(6, r1)
REST_GPR(7, r1)
mtcr r6
mtspr SPRN_DSCR, r7
/* Save away checkpointed SPRs. */
std r0, VCPU_PPR_TM(r9)
mflr r5
mfctr r7
mfspr r8, SPRN_AMR
mfspr r10, SPRN_TAR
mfxer r11
std r5, VCPU_LR_TM(r9)
stw r6, VCPU_CR_TM(r9)
std r7, VCPU_CTR_TM(r9)
std r8, VCPU_AMR_TM(r9)
std r10, VCPU_TAR_TM(r9)
std r11, VCPU_XER_TM(r9)
/* Restore r12 as trap number. */
lwz r12, VCPU_TRAP(r9)
/* Save FP/VSX. */
addi r3, r9, VCPU_FPRS_TM
bl store_fp_state
@ -137,6 +165,11 @@ END_FTR_SECTION_IFSET(CPU_FTR_P9_TM_HV_ASSIST)
bl store_vr_state
mfspr r6, SPRN_VRSAVE
stw r6, VCPU_VRSAVE_TM(r9)
/* Restore non-volatile registers if requested to */
beq cr7, 1f
REST_NVGPRS(r1)
REST_GPR(10, r1)
1:
/*
* We need to save these SPRs after the treclaim so that the software
@ -146,12 +179,16 @@ END_FTR_SECTION_IFSET(CPU_FTR_P9_TM_HV_ASSIST)
*/
mfspr r7, SPRN_TEXASR
std r7, VCPU_TEXASR(r9)
11:
mfspr r5, SPRN_TFHAR
mfspr r6, SPRN_TFIAR
std r5, VCPU_TFHAR(r9)
std r6, VCPU_TFIAR(r9)
/* Restore MSR state if requested */
beq cr7, 2f
mtmsrd r10, 0
2:
addi r1, r1, SWITCH_FRAME_SIZE
ld r0, PPC_LR_STKOFF(r1)
mtlr r0
blr
@ -161,49 +198,22 @@ END_FTR_SECTION_IFSET(CPU_FTR_P9_TM_HV_ASSIST)
* 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/TAR so that it can be recovered later */
mfspr r6, SPRN_DSCR
SAVE_GPR(6, r1)
mfcr r7
stw r7, _CCR(r1)
mflr r0
std r0, PPC_LR_STKOFF(r1)
stdu r1, -PPC_MIN_STKFRM(r1)
mfspr r8, SPRN_TAR
SAVE_GPR(8, r1)
std r8, PPC_MIN_STKFRM-8(r1)
li r5, 1 /* preserve non-volatile registers */
bl __kvmppc_save_tm
REST_GPR(8, r1)
ld r8, PPC_MIN_STKFRM-8(r1)
mtspr SPRN_TAR, r8
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
addi r1, r1, PPC_MIN_STKFRM
ld r0, PPC_LR_STKOFF(r1)
mtlr r0
blr
EXPORT_SYMBOL_GPL(_kvmppc_save_tm_pr);
@ -215,15 +225,21 @@ EXPORT_SYMBOL_GPL(_kvmppc_save_tm_pr);
* - r4 is the guest MSR with desired TS bits:
* For HV KVM, it is VCPU_MSR
* For PR KVM, it is provided by caller
* This potentially modifies all checkpointed registers.
* It restores r1, r2 from the PACA.
* - r5 containing a flag indicating that non-volatile registers
* must be preserved.
* If r5 == 0, this potentially modifies all checkpointed registers, but
* restores r1, r2 from the PACA before exit.
* If r5 != 0, this restores the MSR TM/FP/VEC/VSX bits to their state on entry.
*/
_GLOBAL(__kvmppc_restore_tm)
mflr r0
std r0, PPC_LR_STKOFF(r1)
cmpdi cr7, r5, 0
/* Turn on TM/FP/VSX/VMX so we can restore them. */
mfmsr r5
mr r10, r5
li r6, MSR_TM >> 32
sldi r6, r6, 32
or r5, r5, r6
@ -244,8 +260,7 @@ _GLOBAL(__kvmppc_restore_tm)
mr r5, r4
rldicl. r5, r5, 64 - MSR_TS_S_LG, 62
beqlr /* TM not active in guest */
std r1, HSTATE_SCRATCH2(r13)
beq 9f /* TM not active in guest */
/* 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
@ -255,6 +270,26 @@ _GLOBAL(__kvmppc_restore_tm)
oris r7, r7, (TEXASR_FS)@h
mtspr SPRN_TEXASR, r7
/*
* Make a stack frame and save non-volatile registers if requested.
*/
stdu r1, -SWITCH_FRAME_SIZE(r1)
std r1, HSTATE_SCRATCH2(r13)
mfcr r6
mfspr r7, SPRN_DSCR
SAVE_GPR(2, r1)
SAVE_GPR(6, r1)
SAVE_GPR(7, r1)
beq cr7, 4f
SAVE_NVGPRS(r1)
/* MSR[TS] will be 1 (suspended) once we do trechkpt */
li r0, 1
rldimi r10, r0, MSR_TS_S_LG, 63 - MSR_TS_T_LG
SAVE_GPR(10, r1) /* final MSR value */
4:
/*
* We need to load up the checkpointed state for the guest.
* We need to do this early as it will blow away any GPRs, VSRs and
@ -291,8 +326,6 @@ _GLOBAL(__kvmppc_restore_tm)
ld r29, VCPU_DSCR_TM(r3)
ld r30, VCPU_PPR_TM(r3)
std r2, PACATMSCRATCH(r13) /* Save TOC */
/* Clear the MSR RI since r1, r13 are all going to be foobar. */
li r5, 0
mtmsrd r5, 1
@ -318,18 +351,31 @@ _GLOBAL(__kvmppc_restore_tm)
/* Now let's get back the state we need. */
HMT_MEDIUM
GET_PACA(r13)
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
ld r29, HSTATE_DSCR(r13)
mtspr SPRN_DSCR, r29
#endif
ld r1, HSTATE_SCRATCH2(r13)
ld r2, PACATMSCRATCH(r13)
REST_GPR(7, r1)
mtspr SPRN_DSCR, r7
/* Set the MSR RI since we have our registers back. */
li r5, MSR_RI
mtmsrd r5, 1
/* Restore TOC pointer and CR */
REST_GPR(2, r1)
REST_GPR(6, r1)
mtcr r6
/* Restore non-volatile registers if requested to. */
beq cr7, 5f
REST_GPR(10, r1)
REST_NVGPRS(r1)
5: addi r1, r1, SWITCH_FRAME_SIZE
ld r0, PPC_LR_STKOFF(r1)
mtlr r0
9: /* Restore MSR bits if requested */
beqlr cr7
mtmsrd r10, 0
blr
/*
@ -337,47 +383,23 @@ _GLOBAL(__kvmppc_restore_tm)
* 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/TAR so that it can be recovered later */
mfspr r6, SPRN_DSCR
SAVE_GPR(6, r1)
mfcr r7
stw r7, _CCR(r1)
mflr r0
std r0, PPC_LR_STKOFF(r1)
stdu r1, -PPC_MIN_STKFRM(r1)
/* save TAR so that it can be recovered later */
mfspr r8, SPRN_TAR
SAVE_GPR(8, r1)
std r8, PPC_MIN_STKFRM-8(r1)
li r5, 1
bl __kvmppc_restore_tm
REST_GPR(8, r1)
ld r8, PPC_MIN_STKFRM-8(r1)
mtspr SPRN_TAR, r8
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
addi r1, r1, PPC_MIN_STKFRM
ld r0, PPC_LR_STKOFF(r1)
mtlr r0
blr
EXPORT_SYMBOL_GPL(_kvmppc_restore_tm_pr);