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Commit 800c1065 authored by Thomas Huth's avatar Thomas Huth Committed by Paolo Bonzini
Browse files

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: default avatarThomas Huth <thuth@linux.vnet.ibm.com>
Acked-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent a76ccff6

arch/s390/kvm/diag.c

+1 −3
Original line number Diff line number Diff line
@@ -107,14 +107,13 @@ static int __diag_ipl_functions(struct kvm_vcpu *vcpu) 


static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu)

{

	int ret, idx;

	int ret;



	/* No virtio-ccw notification? Get out quickly. */

	if (!vcpu->kvm->arch.css_support ||

	    (vcpu->run->s.regs.gprs[1] != KVM_S390_VIRTIO_CCW_NOTIFY))

		return -EOPNOTSUPP;



	idx = srcu_read_lock(&vcpu->kvm->srcu);

	/*

	 * The layout is as follows:

	 * - gpr 2 contains the subchannel id (passed as addr)
@@ -125,7 +124,6 @@ static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu) 
				      vcpu->run->s.regs.gprs[2],

				      8, &vcpu->run->s.regs.gprs[3],

				      vcpu->run->s.regs.gprs[4]);

	srcu_read_unlock(&vcpu->kvm->srcu, idx);



	/*

	 * Return cookie in gpr 2, but don't overwrite the register if the

arch/s390/kvm/interrupt.c

+3 −0
Original line number Diff line number Diff line
@@ -436,6 +436,7 @@ int kvm_s390_handle_wait(struct kvm_vcpu *vcpu) 
	hrtimer_start(&vcpu->arch.ckc_timer, ktime_set (0, sltime) , HRTIMER_MODE_REL);

	VCPU_EVENT(vcpu, 5, "enabled wait via clock comparator: %llx ns", sltime);

no_timer:

	srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);

	spin_lock(&vcpu->arch.local_int.float_int->lock);

	spin_lock_bh(&vcpu->arch.local_int.lock);

	add_wait_queue(&vcpu->wq, &wait);
@@ -455,6 +456,8 @@ int kvm_s390_handle_wait(struct kvm_vcpu *vcpu) 
	remove_wait_queue(&vcpu->wq, &wait);

	spin_unlock_bh(&vcpu->arch.local_int.lock);

	spin_unlock(&vcpu->arch.local_int.float_int->lock);

	vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);



	hrtimer_try_to_cancel(&vcpu->arch.ckc_timer);

	return 0;

}

arch/s390/kvm/kvm-s390.c

+12 −0
Original line number Diff line number Diff line
@@ -752,11 +752,18 @@ static int __vcpu_run(struct kvm_vcpu *vcpu) 
{

	int rc, exit_reason;



	/*

	 * We try to hold kvm->srcu during most of vcpu_run (except when run-

	 * ning the guest), so that memslots (and other stuff) are protected

	 */

	vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);



	do {

		rc = vcpu_pre_run(vcpu);

		if (rc)

			break;



		srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);

		/*

		 * As PF_VCPU will be used in fault handler, between

		 * guest_enter and guest_exit should be no uaccess.
@@ -767,10 +774,12 @@ static int __vcpu_run(struct kvm_vcpu *vcpu) 
		exit_reason = sie64a(vcpu->arch.sie_block,

				     vcpu->run->s.regs.gprs);

		kvm_guest_exit();

		vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);



		rc = vcpu_post_run(vcpu, exit_reason);

	} while (!signal_pending(current) && !rc);



	srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);

	return rc;

}
@@ -968,6 +977,7 @@ long kvm_arch_vcpu_ioctl(struct file *filp, 
{

	struct kvm_vcpu *vcpu = filp->private_data;

	void __user *argp = (void __user *)arg;

	int idx;

	long r;



	switch (ioctl) {
@@ -981,7 +991,9 @@ long kvm_arch_vcpu_ioctl(struct file *filp, 
		break;

	}

	case KVM_S390_STORE_STATUS:

		idx = srcu_read_lock(&vcpu->kvm->srcu);

		r = kvm_s390_vcpu_store_status(vcpu, arg);

		srcu_read_unlock(&vcpu->kvm->srcu, idx);

		break;

	case KVM_S390_SET_INITIAL_PSW: {

		psw_t psw;