[XEN PATCH v2 21/25] arm: new VGIC: its: Implement MSI injection in ITS emulation

[Mykyta Poturai <Mykyta_Poturai@epam.com>]

Implement handling of the ITS INT command.
With the help of the IO bus framework we learn the corresponding
ITS from the doorbell address. We then use our wrapper functions to
iterate the linked lists and find the proper Interrupt Translation Table
Entry (ITTE) and thus the corresponding struct vgic_irq to finally set
the pending bit.

Based on Linux commit 2891a7dfb6c4a by Andre Przywara

Signed-off-by: Mykyta Poturai <mykyta_poturai@epam.com>
---
 xen/arch/arm/vgic/vgic-its.c | 112 +++++++++++++++++++++++++++++++++++
 1 file changed, 112 insertions(+)

diff --git a/xen/arch/arm/vgic/vgic-its.c b/xen/arch/arm/vgic/vgic-its.c
index 9a30087d3d..9534b26334 100644
--- a/xen/arch/arm/vgic/vgic-its.c
+++ b/xen/arch/arm/vgic/vgic-its.c
@@ -557,6 +557,81 @@ static u32 max_lpis_propbaser(u64 propbaser)
     return 1U << min(nr_idbits, INTERRUPT_ID_BITS_ITS);
 }
 
+int vgic_its_resolve_lpi(struct domain *d, struct vgic_its *its, u32 devid,
+                         u32 eventid, struct vgic_irq **irq)
+{
+    struct vcpu *vcpu;
+    struct its_ite *ite;
+
+    if ( !its->enabled )
+        return -EBUSY;
+
+    ite = find_ite(its, devid, eventid);
+    if ( !ite || !its_is_collection_mapped(ite->collection) )
+        return E_ITS_INT_UNMAPPED_INTERRUPT;
+
+    vcpu = d->vcpu[ite->collection->target_addr];
+    if ( !vcpu )
+        return E_ITS_INT_UNMAPPED_INTERRUPT;
+
+    if ( !vgic_lpis_enabled(vcpu) )
+        return -EBUSY;
+
+    vgic_its_cache_translation(d, its, devid, eventid, ite->irq);
+
+    *irq = ite->irq;
+    return 0;
+}
+
+int vgic_its_inject_cached_translation(struct domain *d, struct vgic_its *its, u32 devid, u32 eventid)
+{
+	struct vgic_irq *irq;
+	unsigned long flags;
+	paddr_t db;
+
+	db = its->vgic_its_base + GITS_TRANSLATER;
+	irq = vgic_its_check_cache(d, db, devid, eventid);
+	if (!irq)
+		return -EWOULDBLOCK;
+
+	spin_lock_irqsave(&irq->irq_lock, flags);
+	irq->pending_latch = true;
+	vgic_queue_irq_unlock(d, irq, flags);
+
+	return 0;
+}
+
+/*
+ * Find the target VCPU and the LPI number for a given devid/eventid pair
+ * and make this IRQ pending, possibly injecting it.
+ * Must be called with the its_lock mutex held.
+ * Returns 0 on success, a positive error value for any ITS mapping
+ * related errors and negative error values for generic errors.
+ */
+static int vgic_its_trigger_msi(struct domain *d, struct vgic_its *its,
+                                u32 devid, u32 eventid)
+{
+    struct vgic_irq *irq = NULL;
+    unsigned long flags;
+    int err;
+
+	if (!vgic_its_inject_cached_translation(d, its, devid, eventid))
+		return 1;
+
+    err = vgic_its_resolve_lpi(d, its, devid, eventid, &irq);
+    if ( err )
+        return err;
+
+    /* GICv4 style VLPIS are not yet supported */
+    WARN_ON(irq->hw);
+
+    spin_lock_irqsave(&irq->irq_lock, flags);
+    irq->pending_latch = true;
+    vgic_queue_irq_unlock(d, irq, flags);
+
+    return 0;
+}
+
 static u64 its_cmd_mask_field(u64 *its_cmd, int word, int shift, int size)
 {
     return (le64_to_cpu(its_cmd[word]) >> shift) & (BIT(size, ULL) - 1);
@@ -868,6 +943,27 @@ void vgic_its_delete_device(struct domain *d, struct vgic_its_device *its_dev)
     list_del(&its_dev->dev_list);
 }
 
+void vgic_vcpu_inject_lpi(struct domain *d, unsigned int virq)
+{
+    /*
+     * TODO: this assumes that the struct pending_irq stays valid all of
+     * the time. We cannot properly protect this with the current locking
+     * scheme, but the future per-IRQ lock will solve this problem.
+     */
+    struct vgic_irq *p = vgic_get_irq(d, d->vcpu[0], virq);
+    unsigned int vcpu_id;
+
+    if ( !p )
+        return;
+
+    vcpu_id = ACCESS_ONCE(p->target_vcpu->vcpu_id);
+    if ( vcpu_id >= d->max_vcpus )
+          return;
+
+    vgic_put_irq(d, p);
+    vgic_inject_irq(d, d->vcpu[vcpu_id], virq, true);
+}
+
 /*
  * MAPD maps or unmaps a device ID to Interrupt Translation Tables (ITTs).
  * Must be called with the its_lock mutex held.
@@ -1173,6 +1269,19 @@ static int vgic_its_cmd_handle_movall(struct domain *d, struct vgic_its *its,
     return 0;
 }
 
+/*
+ * The INT command injects the LPI associated with that DevID/EvID pair.
+ * Must be called with the its_lock mutex held.
+ */
+static int vgic_its_cmd_handle_int(struct domain *d, struct vgic_its *its,
+                                   u64 *its_cmd)
+{
+    u32 msi_data  = its_cmd_get_id(its_cmd);
+    u64 msi_devid = its_cmd_get_deviceid(its_cmd);
+
+    return vgic_its_trigger_msi(d, its, msi_devid, msi_data);
+}
+
 int vgic_its_inv_lpi(struct domain *d, struct vgic_irq *irq)
 {
     return update_lpi_config(d, irq, NULL, true);
@@ -1288,6 +1397,9 @@ static int vgic_its_handle_command(struct domain *d, struct vgic_its *its,
     case GITS_CMD_MOVALL:
         ret = vgic_its_cmd_handle_movall(d, its, its_cmd);
         break;
+    case GITS_CMD_INT:
+        ret = vgic_its_cmd_handle_int(d, its, its_cmd);
+        break;
     case GITS_CMD_INV:
         ret = vgic_its_cmd_handle_inv(d, its, its_cmd);
         break;
-- 
2.34.1