From 151104a7b3a82f9c56d636595ae58084049d2559 Mon Sep 17 00:00:00 2001 From: Jens Freimann Date: Wed, 8 Feb 2012 08:28:29 +0100 Subject: [PATCH] KVM: s390: make sigp restart return busy when stop pending On reboot the guest sends in smp_send_stop() a sigp stop to all CPUs except for current CPU. Then the guest switches to the IPL cpu by sending a restart to the IPL CPU, followed by a sigp stop to the current cpu. Since restart is handled by userspace it's possible that the restart is delivered before the old stop. This means that the IPL CPU isn't restarted and we have no running CPUs. So let's make sure that there is no stop action pending when we do the restart. Signed-off-by: Jens Freimann Signed-off-by: Christian Borntraeger Signed-off-by: Marcelo Tosatti Signed-off-by: Avi Kivity --- arch/s390/kvm/sigp.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) diff --git a/arch/s390/kvm/sigp.c b/arch/s390/kvm/sigp.c index 30eb0f7..c703b1c 100644 --- a/arch/s390/kvm/sigp.c +++ b/arch/s390/kvm/sigp.c @@ -309,6 +309,34 @@ static int __sigp_sense_running(struct kvm_vcpu *vcpu, u16 cpu_addr, return rc; } +static int __sigp_restart(struct kvm_vcpu *vcpu, u16 cpu_addr) +{ + int rc = 0; + struct kvm_s390_float_interrupt *fi = &vcpu->kvm->arch.float_int; + struct kvm_s390_local_interrupt *li; + + if (cpu_addr >= KVM_MAX_VCPUS) + return 3; /* not operational */ + + spin_lock(&fi->lock); + li = fi->local_int[cpu_addr]; + if (li == NULL) { + rc = 3; /* not operational */ + goto out; + } + + spin_lock_bh(&li->lock); + if (li->action_bits & ACTION_STOP_ON_STOP) + rc = 2; /* busy */ + else + VCPU_EVENT(vcpu, 4, "sigp restart %x to handle userspace", + cpu_addr); + spin_unlock_bh(&li->lock); +out: + spin_unlock(&fi->lock); + return rc; +} + int kvm_s390_handle_sigp(struct kvm_vcpu *vcpu) { int r1 = (vcpu->arch.sie_block->ipa & 0x00f0) >> 4; @@ -372,6 +400,9 @@ int kvm_s390_handle_sigp(struct kvm_vcpu *vcpu) break; case SIGP_RESTART: vcpu->stat.instruction_sigp_restart++; + rc = __sigp_restart(vcpu, cpu_addr); + if (rc == 2) /* busy */ + break; /* user space must know about restart */ default: return -EOPNOTSUPP; -- 2.7.4