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authorOliver Upton <oliver.upton@linux.dev>2024-04-22 23:01:50 +0300
committerMarc Zyngier <maz@kernel.org>2024-04-25 15:19:56 +0300
commitec39bbfd55d07de2e2d4111f35c7ad9523c89ec3 (patch)
tree31c347027da3afb6d0cd6796d8886134c249a770 /arch
parente64f2918c6e7a2c2cbf310d1b571d1a886b91475 (diff)
downloadlinux-ec39bbfd55d07de2e2d4111f35c7ad9523c89ec3.tar.xz
KVM: arm64: vgic-its: Rip out the global translation cache
The MSI injection fast path has been transitioned away from the global translation cache. Rip it out. Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20240422200158.2606761-12-oliver.upton@linux.dev Signed-off-by: Marc Zyngier <maz@kernel.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm64/kvm/vgic/vgic-init.c7
-rw-r--r--arch/arm64/kvm/vgic/vgic-its.c121
-rw-r--r--arch/arm64/kvm/vgic/vgic.h2
3 files changed, 4 insertions, 126 deletions
diff --git a/arch/arm64/kvm/vgic/vgic-init.c b/arch/arm64/kvm/vgic/vgic-init.c
index f20941f83a07..6ee42f395253 100644
--- a/arch/arm64/kvm/vgic/vgic-init.c
+++ b/arch/arm64/kvm/vgic/vgic-init.c
@@ -53,7 +53,6 @@ void kvm_vgic_early_init(struct kvm *kvm)
{
struct vgic_dist *dist = &kvm->arch.vgic;
- 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);
}
@@ -305,9 +304,6 @@ int vgic_init(struct kvm *kvm)
}
}
- if (vgic_has_its(kvm))
- vgic_lpi_translation_cache_init(kvm);
-
/*
* If we have GICv4.1 enabled, unconditionally request enable the
* v4 support so that we get HW-accelerated vSGIs. Otherwise, only
@@ -361,9 +357,6 @@ static void kvm_vgic_dist_destroy(struct kvm *kvm)
dist->vgic_cpu_base = VGIC_ADDR_UNDEF;
}
- if (vgic_has_its(kvm))
- vgic_lpi_translation_cache_destroy(kvm);
-
if (vgic_supports_direct_msis(kvm))
vgic_v4_teardown(kvm);
diff --git a/arch/arm64/kvm/vgic/vgic-its.c b/arch/arm64/kvm/vgic/vgic-its.c
index 9a517faa43ae..bb7f4fd35b2b 100644
--- a/arch/arm64/kvm/vgic/vgic-its.c
+++ b/arch/arm64/kvm/vgic/vgic-its.c
@@ -149,14 +149,6 @@ struct its_ite {
u32 event_id;
};
-struct vgic_translation_cache_entry {
- struct list_head entry;
- phys_addr_t db;
- u32 devid;
- u32 eventid;
- struct vgic_irq *irq;
-};
-
/**
* struct vgic_its_abi - ITS abi ops and settings
* @cte_esz: collection table entry size
@@ -568,96 +560,34 @@ static void vgic_its_cache_translation(struct kvm *kvm, struct vgic_its *its,
struct vgic_irq *irq)
{
unsigned long cache_key = vgic_its_cache_key(devid, eventid);
- struct vgic_dist *dist = &kvm->arch.vgic;
- struct vgic_translation_cache_entry *cte;
struct vgic_irq *old;
- unsigned long flags;
- phys_addr_t db;
/* Do not cache a directly injected interrupt */
if (irq->hw)
return;
- raw_spin_lock_irqsave(&dist->lpi_list_lock, flags);
-
- if (unlikely(list_empty(&dist->lpi_translation_cache)))
- goto out;
-
- db = its->vgic_its_base + GITS_TRANSLATER;
-
- /* Always reuse the last entry (LRU policy) */
- cte = list_last_entry(&dist->lpi_translation_cache,
- typeof(*cte), entry);
-
- /*
- * Caching the translation implies having an extra reference
- * to the interrupt, so drop the potential reference on what
- * was in the cache, and increment it on the new interrupt.
- */
- if (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);
-
- /*
- * Yes, two references are necessary at the moment:
- * - One for the global LPI translation cache
- * - Another for the translation cache belonging to @its
- *
- * This will soon disappear.
- */
- vgic_get_irq_kref(irq);
vgic_get_irq_kref(irq);
- cte->db = db;
- cte->devid = devid;
- cte->eventid = eventid;
- cte->irq = irq;
-
- /* Move the new translation to the head of the list */
- list_move(&cte->entry, &dist->lpi_translation_cache);
- raw_spin_unlock_irqrestore(&dist->lpi_list_lock, flags);
-
/*
- * The per-ITS cache is a perfect cache, so it may already have an
- * identical translation even if it were missing from the global
- * cache. Ensure we don't leak a reference if that is the case.
+ * We could have raced with another CPU caching the same
+ * translation behind our back, ensure we don't leak a
+ * reference if that is the case.
*/
old = xa_store(&its->translation_cache, cache_key, irq, GFP_KERNEL_ACCOUNT);
if (old)
vgic_put_irq(kvm, old);
-
-out:
- raw_spin_unlock_irqrestore(&dist->lpi_list_lock, flags);
}
static void vgic_its_invalidate_cache(struct vgic_its *its)
{
struct kvm *kvm = its->dev->kvm;
- struct vgic_dist *dist = &kvm->arch.vgic;
- struct vgic_translation_cache_entry *cte;
- unsigned long flags, idx;
struct vgic_irq *irq;
-
- raw_spin_lock_irqsave(&dist->lpi_list_lock, flags);
-
- list_for_each_entry(cte, &dist->lpi_translation_cache, entry) {
- /*
- * If we hit a NULL entry, there is nothing after this
- * point.
- */
- if (!cte->irq)
- break;
-
- vgic_put_irq(kvm, cte->irq);
- cte->irq = NULL;
- }
-
- raw_spin_unlock_irqrestore(&dist->lpi_list_lock, flags);
+ unsigned long idx;
xa_for_each(&its->translation_cache, idx, irq) {
xa_erase(&its->translation_cache, idx);
@@ -1880,47 +1810,6 @@ out:
return ret;
}
-/* Default is 16 cached LPIs per vcpu */
-#define LPI_DEFAULT_PCPU_CACHE_SIZE 16
-
-void vgic_lpi_translation_cache_init(struct kvm *kvm)
-{
- struct vgic_dist *dist = &kvm->arch.vgic;
- unsigned int sz;
- int i;
-
- if (!list_empty(&dist->lpi_translation_cache))
- return;
-
- sz = atomic_read(&kvm->online_vcpus) * LPI_DEFAULT_PCPU_CACHE_SIZE;
-
- for (i = 0; i < sz; i++) {
- struct vgic_translation_cache_entry *cte;
-
- /* An allocation failure is not fatal */
- cte = kzalloc(sizeof(*cte), GFP_KERNEL_ACCOUNT);
- if (WARN_ON(!cte))
- break;
-
- INIT_LIST_HEAD(&cte->entry);
- list_add(&cte->entry, &dist->lpi_translation_cache);
- }
-}
-
-void vgic_lpi_translation_cache_destroy(struct kvm *kvm)
-{
- struct vgic_dist *dist = &kvm->arch.vgic;
- struct vgic_translation_cache_entry *cte, *tmp;
-
- vgic_its_invalidate_all_caches(kvm);
-
- list_for_each_entry_safe(cte, tmp,
- &dist->lpi_translation_cache, entry) {
- list_del(&cte->entry);
- kfree(cte);
- }
-}
-
#define INITIAL_BASER_VALUE \
(GIC_BASER_CACHEABILITY(GITS_BASER, INNER, RaWb) | \
GIC_BASER_CACHEABILITY(GITS_BASER, OUTER, SameAsInner) | \
@@ -1953,8 +1842,6 @@ static int vgic_its_create(struct kvm_device *dev, u32 type)
kfree(its);
return ret;
}
-
- vgic_lpi_translation_cache_init(dev->kvm);
}
mutex_init(&its->its_lock);
diff --git a/arch/arm64/kvm/vgic/vgic.h b/arch/arm64/kvm/vgic/vgic.h
index e5cda1eb4bcf..407640c24049 100644
--- a/arch/arm64/kvm/vgic/vgic.h
+++ b/arch/arm64/kvm/vgic/vgic.h
@@ -335,8 +335,6 @@ int vgic_its_resolve_lpi(struct kvm *kvm, struct vgic_its *its,
u32 devid, u32 eventid, struct vgic_irq **irq);
struct vgic_its *vgic_msi_to_its(struct kvm *kvm, struct kvm_msi *msi);
int vgic_its_inject_cached_translation(struct kvm *kvm, struct kvm_msi *msi);
-void vgic_lpi_translation_cache_init(struct kvm *kvm);
-void vgic_lpi_translation_cache_destroy(struct kvm *kvm);
void vgic_its_invalidate_all_caches(struct kvm *kvm);
/* GICv4.1 MMIO interface */