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 contextes, kvm->lock is taken under the
vcpu->mutex which is a forbidden sequence by KVM.
Introduce a new mutex 'lock' for the KVM devices for them to
synchronize accesses to the XIVE device structures.
Signed-off-by: Cédric Le Goater <clg@xxxxxxxx>
---
arch/powerpc/kvm/book3s_xive.h | 1 +
arch/powerpc/kvm/book3s_xive.c | 23 +++++++++++++----------
arch/powerpc/kvm/book3s_xive_native.c | 15 ++++++++-------
3 files changed, 22 insertions(+), 17 deletions(-)
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.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_native.c b/arch/powerpc/kvm/book3s_xive_native.c
index cdce9f94738e..684619517d67 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
--
2.20.1
