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-rw-r--r--arch/arm64/kvm/vgic/vgic-debug.c2
-rw-r--r--arch/arm64/kvm/vgic/vgic-init.c4
-rw-r--r--arch/arm64/kvm/vgic/vgic-its.c55
-rw-r--r--arch/arm64/kvm/vgic/vgic-v3.c3
-rw-r--r--arch/arm64/kvm/vgic/vgic.c60
-rw-r--r--arch/arm64/kvm/vgic/vgic.h15
-rw-r--r--include/kvm/arm_vgic.h9
7 files changed, 79 insertions, 69 deletions
diff --git a/arch/arm64/kvm/vgic/vgic-debug.c b/arch/arm64/kvm/vgic/vgic-debug.c
index 85606a531dc3..389025ce7749 100644
--- a/arch/arm64/kvm/vgic/vgic-debug.c
+++ b/arch/arm64/kvm/vgic/vgic-debug.c
@@ -149,7 +149,7 @@ static void print_dist_state(struct seq_file *s, struct vgic_dist *dist)
seq_printf(s, "vgic_model:\t%s\n", v3 ? "GICv3" : "GICv2");
seq_printf(s, "nr_spis:\t%d\n", dist->nr_spis);
if (v3)
- seq_printf(s, "nr_lpis:\t%d\n", dist->lpi_list_count);
+ seq_printf(s, "nr_lpis:\t%d\n", atomic_read(&dist->lpi_count));
seq_printf(s, "enabled:\t%d\n", dist->enabled);
seq_printf(s, "\n");
diff --git a/arch/arm64/kvm/vgic/vgic-init.c b/arch/arm64/kvm/vgic/vgic-init.c
index df51157420e8..6b1c3b9e8199 100644
--- a/arch/arm64/kvm/vgic/vgic-init.c
+++ b/arch/arm64/kvm/vgic/vgic-init.c
@@ -53,9 +53,9 @@ void kvm_vgic_early_init(struct kvm *kvm)
{
struct vgic_dist *dist = &kvm->arch.vgic;
- INIT_LIST_HEAD(&dist->lpi_list_head);
INIT_LIST_HEAD(&dist->lpi_translation_cache);
raw_spin_lock_init(&dist->lpi_list_lock);
+ xa_init_flags(&dist->lpi_xa, XA_FLAGS_LOCK_IRQ);
}
/* CREATION */
@@ -366,6 +366,8 @@ static void kvm_vgic_dist_destroy(struct kvm *kvm)
if (vgic_supports_direct_msis(kvm))
vgic_v4_teardown(kvm);
+
+ xa_destroy(&dist->lpi_xa);
}
static void __kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu)
diff --git a/arch/arm64/kvm/vgic/vgic-its.c b/arch/arm64/kvm/vgic/vgic-its.c
index c734180a5bcf..2ce842e35e68 100644
--- a/arch/arm64/kvm/vgic/vgic-its.c
+++ b/arch/arm64/kvm/vgic/vgic-its.c
@@ -52,7 +52,12 @@ static struct vgic_irq *vgic_add_lpi(struct kvm *kvm, u32 intid,
if (!irq)
return ERR_PTR(-ENOMEM);
- INIT_LIST_HEAD(&irq->lpi_list);
+ ret = xa_reserve_irq(&dist->lpi_xa, intid, GFP_KERNEL_ACCOUNT);
+ if (ret) {
+ kfree(irq);
+ return ERR_PTR(ret);
+ }
+
INIT_LIST_HEAD(&irq->ap_list);
raw_spin_lock_init(&irq->irq_lock);
@@ -68,30 +73,30 @@ static struct vgic_irq *vgic_add_lpi(struct kvm *kvm, u32 intid,
* There could be a race with another vgic_add_lpi(), so we need to
* check that we don't add a second list entry with the same LPI.
*/
- list_for_each_entry(oldirq, &dist->lpi_list_head, lpi_list) {
- if (oldirq->intid != intid)
- continue;
-
+ oldirq = xa_load(&dist->lpi_xa, intid);
+ if (vgic_try_get_irq_kref(oldirq)) {
/* Someone was faster with adding this LPI, lets use that. */
kfree(irq);
irq = oldirq;
- /*
- * This increases the refcount, the caller is expected to
- * call vgic_put_irq() on the returned pointer once it's
- * finished with the IRQ.
- */
- vgic_get_irq_kref(irq);
+ goto out_unlock;
+ }
+ ret = xa_err(xa_store(&dist->lpi_xa, intid, irq, 0));
+ if (ret) {
+ xa_release(&dist->lpi_xa, intid);
+ kfree(irq);
goto out_unlock;
}
- list_add_tail(&irq->lpi_list, &dist->lpi_list_head);
- dist->lpi_list_count++;
+ atomic_inc(&dist->lpi_count);
out_unlock:
raw_spin_unlock_irqrestore(&dist->lpi_list_lock, flags);
+ if (ret)
+ return ERR_PTR(ret);
+
/*
* We "cache" the configuration table entries in our struct vgic_irq's.
* However we only have those structs for mapped IRQs, so we read in
@@ -311,6 +316,8 @@ static int update_lpi_config(struct kvm *kvm, struct vgic_irq *irq,
return 0;
}
+#define GIC_LPI_MAX_INTID ((1 << INTERRUPT_ID_BITS_ITS) - 1)
+
/*
* Create a snapshot of the current LPIs targeting @vcpu, so that we can
* enumerate those LPIs without holding any lock.
@@ -319,6 +326,7 @@ static int update_lpi_config(struct kvm *kvm, struct vgic_irq *irq,
int vgic_copy_lpi_list(struct kvm *kvm, struct kvm_vcpu *vcpu, u32 **intid_ptr)
{
struct vgic_dist *dist = &kvm->arch.vgic;
+ XA_STATE(xas, &dist->lpi_xa, GIC_LPI_OFFSET);
struct vgic_irq *irq;
unsigned long flags;
u32 *intids;
@@ -331,13 +339,15 @@ int vgic_copy_lpi_list(struct kvm *kvm, struct kvm_vcpu *vcpu, u32 **intid_ptr)
* command). If coming from another path (such as enabling LPIs),
* we must be careful not to overrun the array.
*/
- irq_count = READ_ONCE(dist->lpi_list_count);
+ irq_count = atomic_read(&dist->lpi_count);
intids = kmalloc_array(irq_count, sizeof(intids[0]), GFP_KERNEL_ACCOUNT);
if (!intids)
return -ENOMEM;
raw_spin_lock_irqsave(&dist->lpi_list_lock, flags);
- list_for_each_entry(irq, &dist->lpi_list_head, lpi_list) {
+ rcu_read_lock();
+
+ xas_for_each(&xas, irq, GIC_LPI_MAX_INTID) {
if (i == irq_count)
break;
/* We don't need to "get" the IRQ, as we hold the list lock. */
@@ -345,6 +355,8 @@ int vgic_copy_lpi_list(struct kvm *kvm, struct kvm_vcpu *vcpu, u32 **intid_ptr)
continue;
intids[i++] = irq->intid;
}
+
+ rcu_read_unlock();
raw_spin_unlock_irqrestore(&dist->lpi_list_lock, flags);
*intid_ptr = intids;
@@ -592,8 +604,8 @@ static struct vgic_irq *vgic_its_check_cache(struct kvm *kvm, phys_addr_t db,
raw_spin_lock_irqsave(&dist->lpi_list_lock, flags);
irq = __vgic_its_check_cache(dist, db, devid, eventid);
- if (irq)
- vgic_get_irq_kref(irq);
+ if (!vgic_try_get_irq_kref(irq))
+ irq = NULL;
raw_spin_unlock_irqrestore(&dist->lpi_list_lock, flags);
@@ -637,8 +649,13 @@ static void vgic_its_cache_translation(struct kvm *kvm, struct vgic_its *its,
* was in the cache, and increment it on the new interrupt.
*/
if (cte->irq)
- __vgic_put_lpi_locked(kvm, cte->irq);
+ vgic_put_irq(kvm, cte->irq);
+ /*
+ * The irq refcount is guaranteed to be nonzero while holding the
+ * its_lock, as the ITE (and the reference it holds) cannot be freed.
+ */
+ lockdep_assert_held(&its->its_lock);
vgic_get_irq_kref(irq);
cte->db = db;
@@ -669,7 +686,7 @@ void vgic_its_invalidate_cache(struct kvm *kvm)
if (!cte->irq)
break;
- __vgic_put_lpi_locked(kvm, cte->irq);
+ vgic_put_irq(kvm, cte->irq);
cte->irq = NULL;
}
diff --git a/arch/arm64/kvm/vgic/vgic-v3.c b/arch/arm64/kvm/vgic/vgic-v3.c
index 9465d3706ab9..4ea3340786b9 100644
--- a/arch/arm64/kvm/vgic/vgic-v3.c
+++ b/arch/arm64/kvm/vgic/vgic-v3.c
@@ -380,6 +380,7 @@ int vgic_v3_save_pending_tables(struct kvm *kvm)
struct vgic_irq *irq;
gpa_t last_ptr = ~(gpa_t)0;
bool vlpi_avail = false;
+ unsigned long index;
int ret = 0;
u8 val;
@@ -396,7 +397,7 @@ int vgic_v3_save_pending_tables(struct kvm *kvm)
vlpi_avail = true;
}
- list_for_each_entry(irq, &dist->lpi_list_head, lpi_list) {
+ xa_for_each(&dist->lpi_xa, index, irq) {
int byte_offset, bit_nr;
struct kvm_vcpu *vcpu;
gpa_t pendbase, ptr;
diff --git a/arch/arm64/kvm/vgic/vgic.c b/arch/arm64/kvm/vgic/vgic.c
index db2a95762b1b..f963f410788a 100644
--- a/arch/arm64/kvm/vgic/vgic.c
+++ b/arch/arm64/kvm/vgic/vgic.c
@@ -30,7 +30,8 @@ struct vgic_global kvm_vgic_global_state __ro_after_init = {
* its->its_lock (mutex)
* vgic_cpu->ap_list_lock must be taken with IRQs disabled
* kvm->lpi_list_lock must be taken with IRQs disabled
- * vgic_irq->irq_lock must be taken with IRQs disabled
+ * vgic_dist->lpi_xa.xa_lock must be taken with IRQs disabled
+ * vgic_irq->irq_lock must be taken with IRQs disabled
*
* As the ap_list_lock might be taken from the timer interrupt handler,
* we have to disable IRQs before taking this lock and everything lower
@@ -54,32 +55,22 @@ struct vgic_global kvm_vgic_global_state __ro_after_init = {
*/
/*
- * Iterate over the VM's list of mapped LPIs to find the one with a
- * matching interrupt ID and return a reference to the IRQ structure.
+ * Index the VM's xarray of mapped LPIs and return a reference to the IRQ
+ * structure. The caller is expected to call vgic_put_irq() later once it's
+ * finished with the IRQ.
*/
static struct vgic_irq *vgic_get_lpi(struct kvm *kvm, u32 intid)
{
struct vgic_dist *dist = &kvm->arch.vgic;
struct vgic_irq *irq = NULL;
- unsigned long flags;
-
- raw_spin_lock_irqsave(&dist->lpi_list_lock, flags);
- list_for_each_entry(irq, &dist->lpi_list_head, lpi_list) {
- if (irq->intid != intid)
- continue;
+ rcu_read_lock();
- /*
- * This increases the refcount, the caller is expected to
- * call vgic_put_irq() later once it's finished with the IRQ.
- */
- vgic_get_irq_kref(irq);
- goto out_unlock;
- }
- irq = NULL;
+ irq = xa_load(&dist->lpi_xa, intid);
+ if (!vgic_try_get_irq_kref(irq))
+ irq = NULL;
-out_unlock:
- raw_spin_unlock_irqrestore(&dist->lpi_list_lock, flags);
+ rcu_read_unlock();
return irq;
}
@@ -120,22 +111,6 @@ static void vgic_irq_release(struct kref *ref)
{
}
-/*
- * Drop the refcount on the LPI. Must be called with lpi_list_lock held.
- */
-void __vgic_put_lpi_locked(struct kvm *kvm, struct vgic_irq *irq)
-{
- struct vgic_dist *dist = &kvm->arch.vgic;
-
- if (!kref_put(&irq->refcount, vgic_irq_release))
- return;
-
- list_del(&irq->lpi_list);
- dist->lpi_list_count--;
-
- kfree(irq);
-}
-
void vgic_put_irq(struct kvm *kvm, struct vgic_irq *irq)
{
struct vgic_dist *dist = &kvm->arch.vgic;
@@ -144,9 +119,15 @@ void vgic_put_irq(struct kvm *kvm, struct vgic_irq *irq)
if (irq->intid < VGIC_MIN_LPI)
return;
- raw_spin_lock_irqsave(&dist->lpi_list_lock, flags);
- __vgic_put_lpi_locked(kvm, irq);
- raw_spin_unlock_irqrestore(&dist->lpi_list_lock, flags);
+ if (!kref_put(&irq->refcount, vgic_irq_release))
+ return;
+
+ xa_lock_irqsave(&dist->lpi_xa, flags);
+ __xa_erase(&dist->lpi_xa, irq->intid);
+ xa_unlock_irqrestore(&dist->lpi_xa, flags);
+
+ atomic_dec(&dist->lpi_count);
+ kfree_rcu(irq, rcu);
}
void vgic_flush_pending_lpis(struct kvm_vcpu *vcpu)
@@ -404,7 +385,8 @@ retry:
/*
* Grab a reference to the irq to reflect the fact that it is
- * now in the ap_list.
+ * now in the ap_list. This is safe as the caller must already hold a
+ * reference on the irq.
*/
vgic_get_irq_kref(irq);
list_add_tail(&irq->ap_list, &vcpu->arch.vgic_cpu.ap_list_head);
diff --git a/arch/arm64/kvm/vgic/vgic.h b/arch/arm64/kvm/vgic/vgic.h
index 8d134569d0a1..0c2b82de8fa3 100644
--- a/arch/arm64/kvm/vgic/vgic.h
+++ b/arch/arm64/kvm/vgic/vgic.h
@@ -180,7 +180,6 @@ vgic_get_mmio_region(struct kvm_vcpu *vcpu, struct vgic_io_device *iodev,
gpa_t addr, int len);
struct vgic_irq *vgic_get_irq(struct kvm *kvm, struct kvm_vcpu *vcpu,
u32 intid);
-void __vgic_put_lpi_locked(struct kvm *kvm, struct vgic_irq *irq);
void vgic_put_irq(struct kvm *kvm, struct vgic_irq *irq);
bool vgic_get_phys_line_level(struct vgic_irq *irq);
void vgic_irq_set_phys_pending(struct vgic_irq *irq, bool pending);
@@ -220,12 +219,20 @@ void vgic_v2_vmcr_sync(struct kvm_vcpu *vcpu);
void vgic_v2_save_state(struct kvm_vcpu *vcpu);
void vgic_v2_restore_state(struct kvm_vcpu *vcpu);
-static inline void vgic_get_irq_kref(struct vgic_irq *irq)
+static inline bool vgic_try_get_irq_kref(struct vgic_irq *irq)
{
+ if (!irq)
+ return false;
+
if (irq->intid < VGIC_MIN_LPI)
- return;
+ return true;
- kref_get(&irq->refcount);
+ return kref_get_unless_zero(&irq->refcount);
+}
+
+static inline void vgic_get_irq_kref(struct vgic_irq *irq)
+{
+ WARN_ON_ONCE(!vgic_try_get_irq_kref(irq));
}
void vgic_v3_fold_lr_state(struct kvm_vcpu *vcpu);
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index 8cc38e836f54..47035946648e 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -13,6 +13,7 @@
#include <linux/spinlock.h>
#include <linux/static_key.h>
#include <linux/types.h>
+#include <linux/xarray.h>
#include <kvm/iodev.h>
#include <linux/list.h>
#include <linux/jump_label.h>
@@ -116,7 +117,7 @@ struct irq_ops {
struct vgic_irq {
raw_spinlock_t irq_lock; /* Protects the content of the struct */
- struct list_head lpi_list; /* Used to link all LPIs together */
+ struct rcu_head rcu;
struct list_head ap_list;
struct kvm_vcpu *vcpu; /* SGIs and PPIs: The VCPU
@@ -273,10 +274,10 @@ struct vgic_dist {
*/
u64 propbaser;
- /* Protects the lpi_list and the count value below. */
+ /* Protects the lpi_list. */
raw_spinlock_t lpi_list_lock;
- struct list_head lpi_list_head;
- int lpi_list_count;
+ struct xarray lpi_xa;
+ atomic_t lpi_count;
/* LPI translation cache */
struct list_head lpi_translation_cache;
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-28 11:21:06 +0100