Commit 7e10b9a6 authored by Cédric Le Goater's avatar Cédric Le Goater Committed by Paul Mackerras
Browse files

KVM: PPC: Book3S HV: XIVE: Introduce a new mutex for the XIVE device 



The XICS-on-XIVE KVM device needs to allocate XIVE event queues when a
priority is used by the OS. This is referred as EQ provisioning and it
is done under the hood when :

  1. a CPU is hot-plugged in the VM
  2. the "set-xive" is called at VM startup
  3. sources are restored at VM restore

The kvm->lock mutex is used to protect the different XIVE structures
being modified but in some contexts, kvm->lock is taken under the
vcpu->mutex which is not permitted by the KVM locking rules.

Introduce a new mutex 'lock' for the KVM devices for them to
synchronize accesses to the XIVE device structures.

Reviewed-by: default avatarGreg Kurz <groug@kaod.org>
Signed-off-by: default avatarCédric Le Goater <clg@kaod.org>
Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
parent e717d0ae

arch/powerpc/kvm/book3s_xive.c

+13 −10
Original line number Diff line number Diff line
@@ -271,14 +271,14 @@ static int xive_provision_queue(struct kvm_vcpu *vcpu, u8 prio) 
	return rc;

}



/* Called with kvm_lock held */

/* Called with xive->lock held */

static int xive_check_provisioning(struct kvm *kvm, u8 prio)

{

	struct kvmppc_xive *xive = kvm->arch.xive;

	struct kvm_vcpu *vcpu;

	int i, rc;



	lockdep_assert_held(&kvm->lock);

	lockdep_assert_held(&xive->lock);



	/* Already provisioned ? */

	if (xive->qmap & (1 << prio))
@@ -621,9 +621,12 @@ int kvmppc_xive_set_xive(struct kvm *kvm, u32 irq, u32 server, 
		 irq, server, priority);



	/* First, check provisioning of queues */

	if (priority != MASKED)

	if (priority != MASKED) {

		mutex_lock(&xive->lock);

		rc = xive_check_provisioning(xive->kvm,

			      xive_prio_from_guest(priority));

		mutex_unlock(&xive->lock);

	}

	if (rc) {

		pr_devel("  provisioning failure %d !\n", rc);

		return rc;
@@ -1199,7 +1202,7 @@ int kvmppc_xive_connect_vcpu(struct kvm_device *dev, 
		return -ENOMEM;



	/* We need to synchronize with queue provisioning */

	mutex_lock(&vcpu->kvm->lock);

	mutex_lock(&xive->lock);

	vcpu->arch.xive_vcpu = xc;

	xc->xive = xive;

	xc->vcpu = vcpu;
@@ -1283,7 +1286,7 @@ int kvmppc_xive_connect_vcpu(struct kvm_device *dev, 
		xive_vm_esb_load(&xc->vp_ipi_data, XIVE_ESB_SET_PQ_00);



bail:

	mutex_unlock(&vcpu->kvm->lock);

	mutex_unlock(&xive->lock);

	if (r) {

		kvmppc_xive_cleanup_vcpu(vcpu);

		return r;
@@ -1527,13 +1530,12 @@ static int xive_get_source(struct kvmppc_xive *xive, long irq, u64 addr) 
struct kvmppc_xive_src_block *kvmppc_xive_create_src_block(

	struct kvmppc_xive *xive, int irq)

{

	struct kvm *kvm = xive->kvm;

	struct kvmppc_xive_src_block *sb;

	int i, bid;



	bid = irq >> KVMPPC_XICS_ICS_SHIFT;



	mutex_lock(&kvm->lock);

	mutex_lock(&xive->lock);



	/* block already exists - somebody else got here first */

	if (xive->src_blocks[bid])
@@ -1560,7 +1562,7 @@ struct kvmppc_xive_src_block *kvmppc_xive_create_src_block( 
		xive->max_sbid = bid;



out:

	mutex_unlock(&kvm->lock);

	mutex_unlock(&xive->lock);

	return xive->src_blocks[bid];

}
@@ -1670,9 +1672,9 @@ static int xive_set_source(struct kvmppc_xive *xive, long irq, u64 addr) 
	/* If we have a priority target the interrupt */

	if (act_prio != MASKED) {

		/* First, check provisioning of queues */

		mutex_lock(&xive->kvm->lock);

		mutex_lock(&xive->lock);

		rc = xive_check_provisioning(xive->kvm, act_prio);

		mutex_unlock(&xive->kvm->lock);

		mutex_unlock(&xive->lock);



		/* Target interrupt */

		if (rc == 0)
@@ -1963,6 +1965,7 @@ static int kvmppc_xive_create(struct kvm_device *dev, u32 type) 
	dev->private = xive;

	xive->dev = dev;

	xive->kvm = kvm;

	mutex_init(&xive->lock);



	/* Already there ? */

	if (kvm->arch.xive)

arch/powerpc/kvm/book3s_xive.h

+1 −0
Original line number Diff line number Diff line
@@ -141,6 +141,7 @@ struct kvmppc_xive { 
	struct kvmppc_xive_ops *ops;

	struct address_space   *mapping;

	struct mutex mapping_lock;

	struct mutex lock;

};



#define KVMPPC_XIVE_Q_COUNT	8

arch/powerpc/kvm/book3s_xive_native.c

+8 −7
Original line number Diff line number Diff line
@@ -114,7 +114,7 @@ int kvmppc_xive_native_connect_vcpu(struct kvm_device *dev, 
		return -EINVAL;

	}



	mutex_lock(&vcpu->kvm->lock);

	mutex_lock(&xive->lock);



	if (kvmppc_xive_find_server(vcpu->kvm, server_num)) {

		pr_devel("Duplicate !\n");
@@ -159,7 +159,7 @@ int kvmppc_xive_native_connect_vcpu(struct kvm_device *dev, 


	/* TODO: reset all queues to a clean state ? */

bail:

	mutex_unlock(&vcpu->kvm->lock);

	mutex_unlock(&xive->lock);

	if (rc)

		kvmppc_xive_native_cleanup_vcpu(vcpu);
@@ -772,7 +772,7 @@ static int kvmppc_xive_reset(struct kvmppc_xive *xive) 


	pr_devel("%s\n", __func__);



	mutex_lock(&kvm->lock);

	mutex_lock(&xive->lock);



	kvm_for_each_vcpu(i, vcpu, kvm) {

		struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
@@ -810,7 +810,7 @@ static int kvmppc_xive_reset(struct kvmppc_xive *xive) 
		}

	}



	mutex_unlock(&kvm->lock);

	mutex_unlock(&xive->lock);



	return 0;

}
@@ -878,7 +878,7 @@ static int kvmppc_xive_native_eq_sync(struct kvmppc_xive *xive) 


	pr_devel("%s\n", __func__);



	mutex_lock(&kvm->lock);

	mutex_lock(&xive->lock);

	for (i = 0; i <= xive->max_sbid; i++) {

		struct kvmppc_xive_src_block *sb = xive->src_blocks[i];
@@ -892,7 +892,7 @@ static int kvmppc_xive_native_eq_sync(struct kvmppc_xive *xive) 
	kvm_for_each_vcpu(i, vcpu, kvm) {

		kvmppc_xive_native_vcpu_eq_sync(vcpu);

	}

	mutex_unlock(&kvm->lock);

	mutex_unlock(&xive->lock);



	return 0;

}
@@ -965,7 +965,7 @@ static int kvmppc_xive_native_has_attr(struct kvm_device *dev, 
}



/*

 * Called when device fd is closed

 * Called when device fd is closed.  kvm->lock is held.

 */

static void kvmppc_xive_native_release(struct kvm_device *dev)

{
@@ -1064,6 +1064,7 @@ static int kvmppc_xive_native_create(struct kvm_device *dev, u32 type) 
	xive->kvm = kvm;

	kvm->arch.xive = xive;

	mutex_init(&xive->mapping_lock);

	mutex_init(&xive->lock);



	/*

	 * Allocate a bunch of VPs. KVM_MAX_VCPUS is a large value for

CRA Git | Maintained and supported by SUSTech CRA and CCSE