]> www.infradead.org Git - nvme.git/commitdiff
KVM: arm64: vgic-its: Rip out the global translation cache
authorOliver Upton <oliver.upton@linux.dev>
Mon, 22 Apr 2024 20:01:50 +0000 (20:01 +0000)
committerMarc Zyngier <maz@kernel.org>
Thu, 25 Apr 2024 12:19:56 +0000 (13:19 +0100)
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>
arch/arm64/kvm/vgic/vgic-init.c
arch/arm64/kvm/vgic/vgic-its.c
arch/arm64/kvm/vgic/vgic.h
include/kvm/arm_vgic.h

index f20941f83a077cbc2be093b487e4afe5a29f30ae..6ee42f3952536f97acddc2d3cf2968741d8d81aa 100644 (file)
@@ -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);
 
index 9a517faa43ae61b5b032e271da10ce79892e34ad..bb7f4fd35b2b8d91e36da3180027ca9e9f778b9f 100644 (file)
@@ -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);
index e5cda1eb4bcf4c6b383c47b54a220c5239e3ea79..407640c240494e4a5647527ebb6ca371c09caa9f 100644 (file)
@@ -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 */
index c15e7fcccb8675ac9bfb0c3c771a3bef93997f78..76ed097500c04f3b600fc884388a7677dd2d30a4 100644 (file)
@@ -286,9 +286,6 @@ struct vgic_dist {
 #define LPI_XA_MARK_DEBUG_ITER XA_MARK_0
        struct xarray           lpi_xa;
 
-       /* LPI translation cache */
-       struct list_head        lpi_translation_cache;
-
        /* used by vgic-debug */
        struct vgic_state_iter *iter;