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KVM: s390: Lock kvm->srcu at the appropriate places
The kvm->srcu lock has to be held while accessing the memory of guests and during certain other actions. This patch now adds the locks to the __vcpu_run function so that all affected code is protected now (and additionally to the KVM_S390_STORE_STATUS ioctl, which can be called out-of-band and needs a separate lock). Signed-off-by: Thomas Huth <thuth@linux.vnet.ibm.com> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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parent
a76ccff6f5
commit
800c1065c3
3 changed files with 16 additions and 3 deletions
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@ -107,14 +107,13 @@ static int __diag_ipl_functions(struct kvm_vcpu *vcpu)
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static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu)
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{
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int ret, idx;
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int ret;
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/* No virtio-ccw notification? Get out quickly. */
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if (!vcpu->kvm->arch.css_support ||
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(vcpu->run->s.regs.gprs[1] != KVM_S390_VIRTIO_CCW_NOTIFY))
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return -EOPNOTSUPP;
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idx = srcu_read_lock(&vcpu->kvm->srcu);
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/*
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* The layout is as follows:
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* - gpr 2 contains the subchannel id (passed as addr)
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@ -125,7 +124,6 @@ static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu)
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vcpu->run->s.regs.gprs[2],
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8, &vcpu->run->s.regs.gprs[3],
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vcpu->run->s.regs.gprs[4]);
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srcu_read_unlock(&vcpu->kvm->srcu, idx);
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/*
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* Return cookie in gpr 2, but don't overwrite the register if the
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@ -436,6 +436,7 @@ int kvm_s390_handle_wait(struct kvm_vcpu *vcpu)
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hrtimer_start(&vcpu->arch.ckc_timer, ktime_set (0, sltime) , HRTIMER_MODE_REL);
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VCPU_EVENT(vcpu, 5, "enabled wait via clock comparator: %llx ns", sltime);
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no_timer:
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srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
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spin_lock(&vcpu->arch.local_int.float_int->lock);
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spin_lock_bh(&vcpu->arch.local_int.lock);
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add_wait_queue(&vcpu->wq, &wait);
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@ -455,6 +456,8 @@ int kvm_s390_handle_wait(struct kvm_vcpu *vcpu)
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remove_wait_queue(&vcpu->wq, &wait);
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spin_unlock_bh(&vcpu->arch.local_int.lock);
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spin_unlock(&vcpu->arch.local_int.float_int->lock);
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vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
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hrtimer_try_to_cancel(&vcpu->arch.ckc_timer);
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return 0;
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}
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@ -752,11 +752,18 @@ static int __vcpu_run(struct kvm_vcpu *vcpu)
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{
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int rc, exit_reason;
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/*
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* We try to hold kvm->srcu during most of vcpu_run (except when run-
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* ning the guest), so that memslots (and other stuff) are protected
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*/
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vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
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do {
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rc = vcpu_pre_run(vcpu);
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if (rc)
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break;
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srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
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/*
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* As PF_VCPU will be used in fault handler, between
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* guest_enter and guest_exit should be no uaccess.
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@ -767,10 +774,12 @@ static int __vcpu_run(struct kvm_vcpu *vcpu)
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exit_reason = sie64a(vcpu->arch.sie_block,
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vcpu->run->s.regs.gprs);
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kvm_guest_exit();
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vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
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rc = vcpu_post_run(vcpu, exit_reason);
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} while (!signal_pending(current) && !rc);
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srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
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return rc;
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}
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@ -968,6 +977,7 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
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{
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struct kvm_vcpu *vcpu = filp->private_data;
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void __user *argp = (void __user *)arg;
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int idx;
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long r;
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switch (ioctl) {
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@ -981,7 +991,9 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
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break;
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}
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case KVM_S390_STORE_STATUS:
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idx = srcu_read_lock(&vcpu->kvm->srcu);
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r = kvm_s390_vcpu_store_status(vcpu, arg);
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srcu_read_unlock(&vcpu->kvm->srcu, idx);
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break;
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case KVM_S390_SET_INITIAL_PSW: {
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psw_t psw;
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