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/kvm/book3s_hv.c | |
| 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/kvm/book3s_hv.c')
| -rw-r--r-- | arch/powerpc/kvm/book3s_hv.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 0b436df746fc..8bad44b46dc8 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -2111,6 +2111,15 @@ static int kvmppc_grab_hwthread(int cpu) struct paca_struct *tpaca; long timeout = 10000; + /* + * ISA v3.0 idle routines do not set hwthread_state or test + * hwthread_req, so they can not grab idle threads. + */ + if (cpu_has_feature(CPU_FTR_ARCH_300)) { + WARN(1, "KVM: can not control sibling threads\n"); + return -EBUSY; + } + tpaca = &paca[cpu]; /* Ensure the thread won't go into the kernel if it wakes */ @@ -2145,10 +2154,12 @@ static void kvmppc_release_hwthread(int cpu) struct paca_struct *tpaca; tpaca = &paca[cpu]; - tpaca->kvm_hstate.hwthread_req = 0; tpaca->kvm_hstate.kvm_vcpu = NULL; tpaca->kvm_hstate.kvm_vcore = NULL; tpaca->kvm_hstate.kvm_split_mode = NULL; + if (!cpu_has_feature(CPU_FTR_ARCH_300)) + tpaca->kvm_hstate.hwthread_req = 0; + } static void radix_flush_cpu(struct kvm *kvm, int cpu, struct kvm_vcpu *vcpu) |