diff options
| author | Fan Zhang <zhangfan@linux.vnet.ibm.com> | 2016-08-15 04:53:22 +0200 |
|---|---|---|
| committer | Christian Borntraeger <borntraeger@de.ibm.com> | 2016-09-08 13:40:39 +0200 |
| commit | 80cd8763388b52fa9129cbb4b57a3615a55afd40 (patch) | |
| tree | b3182213435cbe8c3a321c6ed6d8817dc5a4b251 /arch/s390/kvm/kvm-s390.c | |
| parent | c14b88d76624e02b9895914b85b9d8b2c984563c (diff) | |
| download | lwn-80cd8763388b52fa9129cbb4b57a3615a55afd40.tar.gz lwn-80cd8763388b52fa9129cbb4b57a3615a55afd40.zip | |
KVM: s390: lazy enable RI
Only enable runtime instrumentation if the guest issues an RI related
instruction or if userspace changes the riccb to a valid state.
This makes entry/exit a tiny bit faster.
Initial patch by Christian Borntraeger
Signed-off-by: Fan Zhang <zhangfan@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Diffstat (limited to 'arch/s390/kvm/kvm-s390.c')
| -rw-r--r-- | arch/s390/kvm/kvm-s390.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index dead20ae9c00..892abf4653a8 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -1938,8 +1938,6 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu) vcpu->arch.sie_block->eca |= 1; if (sclp.has_sigpif) vcpu->arch.sie_block->eca |= 0x10000000U; - if (test_kvm_facility(vcpu->kvm, 64)) - vcpu->arch.sie_block->ecb3 |= 0x01; if (test_kvm_facility(vcpu->kvm, 129)) { vcpu->arch.sie_block->eca |= 0x00020000; vcpu->arch.sie_block->ecd |= 0x20000000; @@ -2694,6 +2692,19 @@ static void sync_regs(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) if (vcpu->arch.pfault_token == KVM_S390_PFAULT_TOKEN_INVALID) kvm_clear_async_pf_completion_queue(vcpu); } + /* + * If userspace sets the riccb (e.g. after migration) to a valid state, + * we should enable RI here instead of doing the lazy enablement. + */ + if ((kvm_run->kvm_dirty_regs & KVM_SYNC_RICCB) && + test_kvm_facility(vcpu->kvm, 64)) { + struct runtime_instr_cb *riccb = + (struct runtime_instr_cb *) &kvm_run->s.regs.riccb; + + if (riccb->valid) + vcpu->arch.sie_block->ecb3 |= 0x01; + } + kvm_run->kvm_dirty_regs = 0; } |