diff options
| author | Nicholas Piggin <npiggin@gmail.com> | 2017-08-25 14:30:33 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-08-29 14:48:59 +1000 |
| commit | 94a04bc25a2c6296bd0c5e82c10e8231c2b11f77 (patch) | |
| tree | e299908064b8b13718b6f5915d9469d103125b0d /arch/powerpc/kernel/idle_book3s.S | |
| parent | 94171b19c3f1f4d9d4c0e3aaa1aa161def1ec7ea (diff) | |
KVM: PPC: Book3S HV: POWER9 does not require secondary thread management
POWER9 CPUs have independent MMU contexts per thread, so KVM does not
need to quiesce secondary threads, so the hwthread_req/hwthread_state
protocol does not have to be used. So patch it away on POWER9, and patch
away the branch from the Linux idle wakeup to kvm_start_guest that is
never used.
Add a warning and error out of kvmppc_grab_hwthread in case it is ever
called on POWER9.
This avoids a hwsync in the idle wakeup path on POWER9.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Paul Mackerras <paulus@ozlabs.org>
[mpe: Use WARN(...) instead of WARN_ON()/pr_err(...)]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel/idle_book3s.S')
| -rw-r--r-- | arch/powerpc/kernel/idle_book3s.S | 35 |
1 files changed, 24 insertions, 11 deletions
diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S index 516ebef905c0..294d024bfb61 100644 --- a/arch/powerpc/kernel/idle_book3s.S +++ b/arch/powerpc/kernel/idle_book3s.S @@ -242,13 +242,20 @@ enter_winkle: /* * r3 - PSSCR value corresponding to the requested stop state. */ -power_enter_stop: #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE - /* Tell KVM we're entering idle */ +power_enter_stop_kvm_rm: + /* + * This is currently unused because POWER9 KVM does not have to + * gather secondary threads into sibling mode, but the code is + * here in case that function is required. + * + * Tell KVM we're entering idle. + */ li r4,KVM_HWTHREAD_IN_IDLE /* DO THIS IN REAL MODE! See comment above. */ stb r4,HSTATE_HWTHREAD_STATE(r13) #endif +power_enter_stop: /* * Check if we are executing the lite variant with ESL=EC=0 */ @@ -411,6 +418,18 @@ pnv_powersave_wakeup_mce: b pnv_powersave_wakeup +#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE +kvm_start_guest_check: + li r0,KVM_HWTHREAD_IN_KERNEL + stb r0,HSTATE_HWTHREAD_STATE(r13) + /* Order setting hwthread_state vs. testing hwthread_req */ + sync + lbz r0,HSTATE_HWTHREAD_REQ(r13) + cmpwi r0,0 + beqlr + b kvm_start_guest +#endif + /* * Called from reset vector for powersave wakeups. * cr3 - set to gt if waking up with partial/complete hypervisor state loss @@ -435,15 +454,9 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_ARCH_300) mr r3,r12 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE - li r0,KVM_HWTHREAD_IN_KERNEL - stb r0,HSTATE_HWTHREAD_STATE(r13) - /* Order setting hwthread_state vs. testing hwthread_req */ - sync - lbz r0,HSTATE_HWTHREAD_REQ(r13) - cmpwi r0,0 - beq 1f - b kvm_start_guest -1: +BEGIN_FTR_SECTION + bl kvm_start_guest_check +END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300) #endif /* Return SRR1 from power7_nap() */ |