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| author | Paul Mackerras | 2016-11-18 04:34:07 +0100 |
|---|---|---|
| committer | Paul Mackerras | 2016-11-23 23:24:23 +0100 |
| commit | bf53c88e42ac5dfdef649888d01b3bc96375647b (patch) | |
| tree | cdd6ddb2340db19c2c61d60ed7d01d6e9c60503f /arch/powerpc | |
| parent | KVM: PPC: Book3S HV: Use OPAL XICS emulation on POWER9 (diff) | |
| download | kernel-qcow2-linux-bf53c88e42ac5dfdef649888d01b3bc96375647b.tar.gz kernel-qcow2-linux-bf53c88e42ac5dfdef649888d01b3bc96375647b.tar.xz kernel-qcow2-linux-bf53c88e42ac5dfdef649888d01b3bc96375647b.zip | |
KVM: PPC: Book3S HV: Use stop instruction rather than nap on POWER9
POWER9 replaces the various power-saving mode instructions on POWER8
(doze, nap, sleep and rvwinkle) with a single "stop" instruction, plus
a register, PSSCR, which controls the depth of the power-saving mode.
This replaces the use of the nap instruction when threads are idle
during guest execution with the stop instruction, and adds code to
set PSSCR to a value which will allow an SMT mode switch while the
thread is idle (given that the core as a whole won't be idle in these
cases).
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/kvm/book3s_hv_rmhandlers.S | 33 |
1 files changed, 22 insertions, 11 deletions
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S index 598d8281fc05..9338a818e05c 100644 --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -501,17 +501,9 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) cmpwi r0, 0 beq 57f li r3, (LPCR_PECEDH | LPCR_PECE0) >> 4 - mfspr r4, SPRN_LPCR - rlwimi r4, r3, 4, (LPCR_PECEDP | LPCR_PECEDH | LPCR_PECE0 | LPCR_PECE1) - mtspr SPRN_LPCR, r4 - isync - std r0, HSTATE_SCRATCH0(r13) - ptesync - ld r0, HSTATE_SCRATCH0(r13) -1: cmpd r0, r0 - bne 1b - nap - b . + mfspr r5, SPRN_LPCR + rlwimi r5, r3, 4, (LPCR_PECEDP | LPCR_PECEDH | LPCR_PECE0 | LPCR_PECE1) + b kvm_nap_sequence 57: li r0, 0 stbx r0, r3, r4 @@ -2256,6 +2248,21 @@ BEGIN_FTR_SECTION ori r5, r5, LPCR_PECEDH rlwimi r5, r3, 0, LPCR_PECEDP END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) + +kvm_nap_sequence: /* desired LPCR value in r5 */ +BEGIN_FTR_SECTION + /* + * PSSCR bits: exit criterion = 1 (wakeup based on LPCR at sreset) + * enable state loss = 1 (allow SMT mode switch) + * requested level = 0 (just stop dispatching) + */ + lis r3, (PSSCR_EC | PSSCR_ESL)@h + mtspr SPRN_PSSCR, r3 + /* Set LPCR_PECE_HVEE bit to enable wakeup by HV interrupts */ + li r4, LPCR_PECE_HVEE@higher + sldi r4, r4, 32 + or r5, r5, r4 +END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300) mtspr SPRN_LPCR,r5 isync li r0, 0 @@ -2264,7 +2271,11 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) ld r0, HSTATE_SCRATCH0(r13) 1: cmpd r0, r0 bne 1b +BEGIN_FTR_SECTION nap +FTR_SECTION_ELSE + PPC_STOP +ALT_FTR_SECTION_END_IFCLR(CPU_FTR_ARCH_300) b . 33: mr r4, r3 |