From 9957c86d659a4d5a2bed25ccbd3bfc9c3f25e658 Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Mon, 30 Jun 2014 20:51:11 +1000 Subject: [PATCH] KVM: Move all accesses to kvm::irq_routing into irqchip.c Now that struct _irqfd does not keep a reference to storage pointed to by the irq_routing field of struct kvm, we can move the statement that updates it out from under the irqfds.lock and put it in kvm_set_irq_routing() instead. That means we then have to take a srcu_read_lock on kvm->irq_srcu around the irqfd_update call in kvm_irqfd_assign(), since holding the kvm->irqfds.lock no longer ensures that that the routing can't change. Combined with changing kvm_irq_map_gsi() and kvm_irq_map_chip_pin() to take a struct kvm * argument instead of the pointer to the routing table, this allows us to to move all references to kvm->irq_routing into irqchip.c. That in turn allows us to move the definition of the kvm_irq_routing_table struct into irqchip.c as well. Signed-off-by: Paul Mackerras Tested-by: Eric Auger Tested-by: Cornelia Huck Signed-off-by: Paolo Bonzini --- include/linux/kvm_host.h | 35 +++++++---------------------------- virt/kvm/eventfd.c | 22 +++++++++------------- virt/kvm/irq_comm.c | 6 ++---- virt/kvm/irqchip.c | 39 +++++++++++++++++++++++++-------------- 4 files changed, 43 insertions(+), 59 deletions(-) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 4956149e962a..ddd33e1aeee1 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -325,24 +325,7 @@ struct kvm_kernel_irq_routing_entry { struct hlist_node link; }; -#ifdef CONFIG_HAVE_KVM_IRQ_ROUTING - -struct kvm_irq_routing_table { - int chip[KVM_NR_IRQCHIPS][KVM_IRQCHIP_NUM_PINS]; - struct kvm_kernel_irq_routing_entry *rt_entries; - u32 nr_rt_entries; - /* - * Array indexed by gsi. Each entry contains list of irq chips - * the gsi is connected to. - */ - struct hlist_head map[0]; -}; - -#else - -struct kvm_irq_routing_table {}; - -#endif +struct kvm_irq_routing_table; #ifndef KVM_PRIVATE_MEM_SLOTS #define KVM_PRIVATE_MEM_SLOTS 0 @@ -401,8 +384,7 @@ struct kvm { struct mutex irq_lock; #ifdef CONFIG_HAVE_KVM_IRQCHIP /* - * Update side is protected by irq_lock and, - * if configured, irqfds.lock. + * Update side is protected by irq_lock. */ struct kvm_irq_routing_table __rcu *irq_routing; struct hlist_head mask_notifier_list; @@ -752,10 +734,9 @@ void kvm_unregister_irq_mask_notifier(struct kvm *kvm, int irq, void kvm_fire_mask_notifiers(struct kvm *kvm, unsigned irqchip, unsigned pin, bool mask); -int kvm_irq_map_gsi(struct kvm_kernel_irq_routing_entry *entries, - struct kvm_irq_routing_table *irq_rt, int gsi); -int kvm_irq_map_chip_pin(struct kvm_irq_routing_table *irq_rt, - unsigned irqchip, unsigned pin); +int kvm_irq_map_gsi(struct kvm *kvm, + struct kvm_kernel_irq_routing_entry *entries, int gsi); +int kvm_irq_map_chip_pin(struct kvm *kvm, unsigned irqchip, unsigned pin); int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level, bool line_status); @@ -967,7 +948,7 @@ int kvm_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args); #ifdef CONFIG_HAVE_KVM_IRQCHIP int kvm_irqfd(struct kvm *kvm, struct kvm_irqfd *args); void kvm_irqfd_release(struct kvm *kvm); -void kvm_irq_routing_update(struct kvm *, struct kvm_irq_routing_table *); +void kvm_irq_routing_update(struct kvm *); #else static inline int kvm_irqfd(struct kvm *kvm, struct kvm_irqfd *args) { @@ -989,10 +970,8 @@ static inline int kvm_irqfd(struct kvm *kvm, struct kvm_irqfd *args) static inline void kvm_irqfd_release(struct kvm *kvm) {} #ifdef CONFIG_HAVE_KVM_IRQCHIP -static inline void kvm_irq_routing_update(struct kvm *kvm, - struct kvm_irq_routing_table *irq_rt) +static inline void kvm_irq_routing_update(struct kvm *kvm) { - rcu_assign_pointer(kvm->irq_routing, irq_rt); } #endif diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c index 15fa9488b2d0..f0075ffb0c35 100644 --- a/virt/kvm/eventfd.c +++ b/virt/kvm/eventfd.c @@ -278,14 +278,13 @@ irqfd_ptable_queue_proc(struct file *file, wait_queue_head_t *wqh, } /* Must be called under irqfds.lock */ -static void irqfd_update(struct kvm *kvm, struct _irqfd *irqfd, - struct kvm_irq_routing_table *irq_rt) +static void irqfd_update(struct kvm *kvm, struct _irqfd *irqfd) { struct kvm_kernel_irq_routing_entry *e; struct kvm_kernel_irq_routing_entry entries[KVM_NR_IRQCHIPS]; int i, n_entries; - n_entries = kvm_irq_map_gsi(entries, irq_rt, irqfd->gsi); + n_entries = kvm_irq_map_gsi(kvm, entries, irqfd->gsi); write_seqcount_begin(&irqfd->irq_entry_sc); @@ -304,12 +303,12 @@ static void irqfd_update(struct kvm *kvm, struct _irqfd *irqfd, static int kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args) { - struct kvm_irq_routing_table *irq_rt; struct _irqfd *irqfd, *tmp; struct fd f; struct eventfd_ctx *eventfd = NULL, *resamplefd = NULL; int ret; unsigned int events; + int idx; irqfd = kzalloc(sizeof(*irqfd), GFP_KERNEL); if (!irqfd) @@ -403,9 +402,9 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args) goto fail; } - irq_rt = rcu_dereference_protected(kvm->irq_routing, - lockdep_is_held(&kvm->irqfds.lock)); - irqfd_update(kvm, irqfd, irq_rt); + idx = srcu_read_lock(&kvm->irq_srcu); + irqfd_update(kvm, irqfd); + srcu_read_unlock(&kvm->irq_srcu, idx); list_add_tail(&irqfd->list, &kvm->irqfds.items); @@ -539,20 +538,17 @@ kvm_irqfd_release(struct kvm *kvm) } /* - * Change irq_routing and irqfd. + * Take note of a change in irq routing. * Caller must invoke synchronize_srcu(&kvm->irq_srcu) afterwards. */ -void kvm_irq_routing_update(struct kvm *kvm, - struct kvm_irq_routing_table *irq_rt) +void kvm_irq_routing_update(struct kvm *kvm) { struct _irqfd *irqfd; spin_lock_irq(&kvm->irqfds.lock); - rcu_assign_pointer(kvm->irq_routing, irq_rt); - list_for_each_entry(irqfd, &kvm->irqfds.items, list) - irqfd_update(kvm, irqfd, irq_rt); + irqfd_update(kvm, irqfd); spin_unlock_irq(&kvm->irqfds.lock); } diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c index 175844593243..963b8995a9e8 100644 --- a/virt/kvm/irq_comm.c +++ b/virt/kvm/irq_comm.c @@ -163,7 +163,6 @@ int kvm_set_irq_inatomic(struct kvm *kvm, int irq_source_id, u32 irq, int level) struct kvm_kernel_irq_routing_entry entries[KVM_NR_IRQCHIPS]; struct kvm_kernel_irq_routing_entry *e; int ret = -EINVAL; - struct kvm_irq_routing_table *irq_rt; int idx; trace_kvm_set_irq(irq, level, irq_source_id); @@ -177,8 +176,7 @@ int kvm_set_irq_inatomic(struct kvm *kvm, int irq_source_id, u32 irq, int level) * which is limited to 1:1 GSI mapping. */ idx = srcu_read_lock(&kvm->irq_srcu); - irq_rt = srcu_dereference(kvm->irq_routing, &kvm->irq_srcu); - if (kvm_irq_map_gsi(entries, irq_rt, irq) > 0) { + if (kvm_irq_map_gsi(kvm, entries, irq) > 0) { e = &entries[0]; if (likely(e->type == KVM_IRQ_ROUTING_MSI)) ret = kvm_set_msi_inatomic(e, kvm); @@ -264,7 +262,7 @@ void kvm_fire_mask_notifiers(struct kvm *kvm, unsigned irqchip, unsigned pin, int idx, gsi; idx = srcu_read_lock(&kvm->irq_srcu); - gsi = srcu_dereference(kvm->irq_routing, &kvm->irq_srcu)->chip[irqchip][pin]; + gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin); if (gsi != -1) hlist_for_each_entry_rcu(kimn, &kvm->mask_notifier_list, link) if (kimn->irq == gsi) diff --git a/virt/kvm/irqchip.c b/virt/kvm/irqchip.c index f4648dd94888..04faac50cef5 100644 --- a/virt/kvm/irqchip.c +++ b/virt/kvm/irqchip.c @@ -31,12 +31,26 @@ #include #include "irq.h" -int kvm_irq_map_gsi(struct kvm_kernel_irq_routing_entry *entries, - struct kvm_irq_routing_table *irq_rt, int gsi) +struct kvm_irq_routing_table { + int chip[KVM_NR_IRQCHIPS][KVM_IRQCHIP_NUM_PINS]; + struct kvm_kernel_irq_routing_entry *rt_entries; + u32 nr_rt_entries; + /* + * Array indexed by gsi. Each entry contains list of irq chips + * the gsi is connected to. + */ + struct hlist_head map[0]; +}; + +int kvm_irq_map_gsi(struct kvm *kvm, + struct kvm_kernel_irq_routing_entry *entries, int gsi) { + struct kvm_irq_routing_table *irq_rt; struct kvm_kernel_irq_routing_entry *e; int n = 0; + irq_rt = srcu_dereference_check(kvm->irq_routing, &kvm->irq_srcu, + lockdep_is_held(&kvm->irq_lock)); if (gsi < irq_rt->nr_rt_entries) { hlist_for_each_entry(e, &irq_rt->map[gsi], link) { entries[n] = *e; @@ -47,21 +61,21 @@ int kvm_irq_map_gsi(struct kvm_kernel_irq_routing_entry *entries, return n; } -int kvm_irq_map_chip_pin(struct kvm_irq_routing_table *irq_rt, - unsigned irqchip, unsigned pin) +int kvm_irq_map_chip_pin(struct kvm *kvm, unsigned irqchip, unsigned pin) { + struct kvm_irq_routing_table *irq_rt; + + irq_rt = srcu_dereference(kvm->irq_routing, &kvm->irq_srcu); return irq_rt->chip[irqchip][pin]; } bool kvm_irq_has_notifier(struct kvm *kvm, unsigned irqchip, unsigned pin) { - struct kvm_irq_routing_table *irq_rt; struct kvm_irq_ack_notifier *kian; int gsi, idx; idx = srcu_read_lock(&kvm->irq_srcu); - irq_rt = srcu_dereference(kvm->irq_routing, &kvm->irq_srcu); - gsi = kvm_irq_map_chip_pin(irq_rt, irqchip, pin); + gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin); if (gsi != -1) hlist_for_each_entry_rcu(kian, &kvm->irq_ack_notifier_list, link) @@ -78,15 +92,13 @@ EXPORT_SYMBOL_GPL(kvm_irq_has_notifier); void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin) { - struct kvm_irq_routing_table *irq_rt; struct kvm_irq_ack_notifier *kian; int gsi, idx; trace_kvm_ack_irq(irqchip, pin); idx = srcu_read_lock(&kvm->irq_srcu); - irq_rt = srcu_dereference(kvm->irq_routing, &kvm->irq_srcu); - gsi = kvm_irq_map_chip_pin(irq_rt, irqchip, pin); + gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin); if (gsi != -1) hlist_for_each_entry_rcu(kian, &kvm->irq_ack_notifier_list, link) @@ -143,7 +155,6 @@ int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level, { struct kvm_kernel_irq_routing_entry irq_set[KVM_NR_IRQCHIPS]; int ret = -1, i, idx; - struct kvm_irq_routing_table *irq_rt; trace_kvm_set_irq(irq, level, irq_source_id); @@ -152,8 +163,7 @@ int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level, * writes to the unused one. */ idx = srcu_read_lock(&kvm->irq_srcu); - irq_rt = srcu_dereference(kvm->irq_routing, &kvm->irq_srcu); - i = kvm_irq_map_gsi(irq_set, irq_rt, irq); + i = kvm_irq_map_gsi(kvm, irq_set, irq); srcu_read_unlock(&kvm->irq_srcu, idx); while(i--) { @@ -250,7 +260,8 @@ int kvm_set_irq_routing(struct kvm *kvm, mutex_lock(&kvm->irq_lock); old = kvm->irq_routing; - kvm_irq_routing_update(kvm, new); + rcu_assign_pointer(kvm->irq_routing, new); + kvm_irq_routing_update(kvm); mutex_unlock(&kvm->irq_lock); synchronize_srcu_expedited(&kvm->irq_srcu); -- 2.20.1