KVM: arm/arm64: vgic: Add LPI translation cache definition

Add the basic data structure that expresses an MSI to LPI
translation as well as the allocation/release hooks.

The size of the cache is arbitrarily defined as 16*nr_vcpus.

Tested-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>

3 files changed, 56 insertions, 0 deletions

diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c
index bdbc297d06fb..80127ca9269f 100644
--- a/virt/kvm/arm/vgic/vgic-init.c
+++ b/virt/kvm/arm/vgic/vgic-init.c
@@ -53,6 +53,7 @@ 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);
 }
 
@@ -294,6 +295,7 @@ int vgic_init(struct kvm *kvm)
         }
 
         if (vgic_has_its(kvm)) {
+                vgic_lpi_translation_cache_init(kvm);
                 ret = vgic_v4_init(kvm);
                 if (ret)
                         goto out;
@@ -335,6 +337,9 @@ static void kvm_vgic_dist_destroy(struct kvm *kvm)
                 INIT_LIST_HEAD(&dist->rd_regions);
         }
 
+        if (vgic_has_its(kvm))
+                vgic_lpi_translation_cache_destroy(kvm);
+
         if (vgic_supports_direct_msis(kvm))
                 vgic_v4_teardown(kvm);
 }
diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 482036612adf..0e5c1519bbe2 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -138,6 +138,14 @@ 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
@@ -1657,6 +1665,45 @@ 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);
+                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;
+
+        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)         | \
@@ -1685,6 +1732,8 @@ 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/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
index 797e05004d80..a25b790ffa4e 100644
--- a/virt/kvm/arm/vgic/vgic.h
+++ b/virt/kvm/arm/vgic/vgic.h
@@ -307,6 +307,8 @@ int vgic_copy_lpi_list(struct kvm *kvm, struct kvm_vcpu *vcpu, u32 **intid_ptr);
 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);
+void vgic_lpi_translation_cache_init(struct kvm *kvm);
+void vgic_lpi_translation_cache_destroy(struct kvm *kvm);
 
 bool vgic_supports_direct_msis(struct kvm *kvm);
 int vgic_v4_init(struct kvm *kvm);