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 <paulus@xxxxxxxxx>
---
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 4530753..2346029 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 15fa948..f0075ff 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 6e73af2..7f9ad65 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 f4648dd..04faac5 100644
--- a/virt/kvm/irqchip.c
+++ b/virt/kvm/irqchip.c
@@ -31,12 +31,26 @@
#include <trace/events/kvm.h>
#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);
--
2.0.0
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