From 7e10b9a6da619bcee243980d9c45112761a86e11 Mon Sep 17 00:00:00 2001 From: =?utf8?q?C=C3=A9dric=20Le=20Goater?= Date: Fri, 24 May 2019 15:20:30 +0200 Subject: [PATCH] KVM: PPC: Book3S HV: XIVE: Introduce a new mutex for the XIVE device MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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: Greg Kurz Signed-off-by: Cédric Le Goater Signed-off-by: Paul Mackerras --- arch/powerpc/kvm/book3s_xive.c | 23 +++++++++++++---------- arch/powerpc/kvm/book3s_xive.h | 1 + arch/powerpc/kvm/book3s_xive_native.c | 15 ++++++++------- 3 files changed, 22 insertions(+), 17 deletions(-) diff --git a/arch/powerpc/kvm/book3s_xive.c b/arch/powerpc/kvm/book3s_xive.c index f623451ec0a3..12c8a36dd980 100644 --- a/arch/powerpc/kvm/book3s_xive.c +++ b/arch/powerpc/kvm/book3s_xive.c @@ -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) diff --git a/arch/powerpc/kvm/book3s_xive.h b/arch/powerpc/kvm/book3s_xive.h index 426146332984..862c2c9650ae 100644 --- a/arch/powerpc/kvm/book3s_xive.h +++ b/arch/powerpc/kvm/book3s_xive.h @@ -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 diff --git a/arch/powerpc/kvm/book3s_xive_native.c b/arch/powerpc/kvm/book3s_xive_native.c index 3caf64b96f7e..fec3b85411ef 100644 --- a/arch/powerpc/kvm/book3s_xive_native.c +++ b/arch/powerpc/kvm/book3s_xive_native.c @@ -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 -- 2.30.2