spapr: Move interrupt allocator to xics

The current allocator returns IRQ numbers from a pool and does not
support IRQs reuse in any form as it did not keep track of what it
previously returned, it only keeps the last returned IRQ. Some use
cases such as PCI hot(un)plug may require IRQ release and reallocation.

This moves an allocator from SPAPR to XICS.

This switches IRQ users to use new API.

This uses LSI/MSI flags to know if interrupt is allocated.

The interrupt release function will be posted as a separate patch.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Alexander Graf <agraf@suse.de>

5 files changed, 93 insertions, 72 deletions

diff --git a/hw/intc/xics.c b/hw/intc/xics.c
index 634101ac23..6cd980a735 100644
--- a/hw/intc/xics.c
+++ b/hw/intc/xics.c
@@ -687,6 +687,94 @@ void xics_set_irq_type(XICSState *icp, int irq, bool lsi)
     ics_set_irq_type(ics, irq - ics->offset, lsi);
 }
 
+#define ICS_IRQ_FREE(ics, srcno)   \
+    (!((ics)->irqs[(srcno)].flags & (XICS_FLAGS_IRQ_MASK)))
+
+static int ics_find_free_block(ICSState *ics, int num, int alignnum)
+{
+    int first, i;
+
+    for (first = 0; first < ics->nr_irqs; first += alignnum) {
+        if (num > (ics->nr_irqs - first)) {
+            return -1;
+        }
+        for (i = first; i < first + num; ++i) {
+            if (!ICS_IRQ_FREE(ics, i)) {
+                break;
+            }
+        }
+        if (i == (first + num)) {
+            return first;
+        }
+    }
+
+    return -1;
+}
+
+int xics_alloc(XICSState *icp, int src, int irq_hint, bool lsi)
+{
+    ICSState *ics = &icp->ics[src];
+    int irq;
+
+    if (irq_hint) {
+        assert(src == xics_find_source(icp, irq_hint));
+        if (!ICS_IRQ_FREE(ics, irq_hint - ics->offset)) {
+            trace_xics_alloc_failed_hint(src, irq_hint);
+            return -1;
+        }
+        irq = irq_hint;
+    } else {
+        irq = ics_find_free_block(ics, 1, 1);
+        if (irq < 0) {
+            trace_xics_alloc_failed_no_left(src);
+            return -1;
+        }
+        irq += ics->offset;
+    }
+
+    ics_set_irq_type(ics, irq - ics->offset, lsi);
+    trace_xics_alloc(src, irq);
+
+    return irq;
+}
+
+/*
+ * Allocate block of consequtive IRQs, returns a number of the first.
+ * If align==true, aligns the first IRQ number to num.
+ */
+int xics_alloc_block(XICSState *icp, int src, int num, bool lsi, bool align)
+{
+    int i, first = -1;
+    ICSState *ics = &icp->ics[src];
+
+    assert(src == 0);
+    /*
+     * MSIMesage::data is used for storing VIRQ so
+     * it has to be aligned to num to support multiple
+     * MSI vectors. MSI-X is not affected by this.
+     * The hint is used for the first IRQ, the rest should
+     * be allocated continuously.
+     */
+    if (align) {
+        assert((num == 1) || (num == 2) || (num == 4) ||
+               (num == 8) || (num == 16) || (num == 32));
+        first = ics_find_free_block(ics, num, num);
+    } else {
+        first = ics_find_free_block(ics, num, 1);
+    }
+
+    if (first >= 0) {
+        for (i = first; i < first + num; ++i) {
+            ics_set_irq_type(ics, i, lsi);
+        }
+    }
+    first += ics->offset;
+
+    trace_xics_alloc_block(src, first, num, lsi, align);
+
+    return first;
+}
+
 /*
  * Guest interfaces
  */
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 8d14f6b993..ea9bda9a68 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -104,73 +104,6 @@ struct sPAPRMachineState {
 
 sPAPREnvironment *spapr;
 
-int spapr_allocate_irq(int hint, bool lsi)
-{
-    int irq;
-
-    if (hint) {
-        irq = hint;
-        if (hint >= spapr->next_irq) {
-            spapr->next_irq = hint + 1;
-        }
-        /* FIXME: we should probably check for collisions somehow */
-    } else {
-        irq = spapr->next_irq++;
-    }
-
-    /* Configure irq type */
-    if (!xics_get_qirq(spapr->icp, irq)) {
-        return 0;
-    }
-
-    xics_set_irq_type(spapr->icp, irq, lsi);
-
-    return irq;
-}
-
-/*
- * Allocate block of consequtive IRQs, returns a number of the first.
- * If msi==true, aligns the first IRQ number to num.
- */
-int spapr_allocate_irq_block(int num, bool lsi, bool msi)
-{
-    int first = -1;
-    int i, hint = 0;
-
-    /*
-     * MSIMesage::data is used for storing VIRQ so
-     * it has to be aligned to num to support multiple
-     * MSI vectors. MSI-X is not affected by this.
-     * The hint is used for the first IRQ, the rest should
-     * be allocated continuously.
-     */
-    if (msi) {
-        assert((num == 1) || (num == 2) || (num == 4) ||
-               (num == 8) || (num == 16) || (num == 32));
-        hint = (spapr->next_irq + num - 1) & ~(num - 1);
-    }
-
-    for (i = 0; i < num; ++i) {
-        int irq;
-
-        irq = spapr_allocate_irq(hint, lsi);
-        if (!irq) {
-            return -1;
-        }
-
-        if (0 == i) {
-            first = irq;
-            hint = 0;
-        }
-
-        /* If the above doesn't create a consecutive block then that's
-         * an internal bug */
-        assert(irq == (first + i));
-    }
-
-    return first;
-}
-
 static XICSState *try_create_xics(const char *type, int nr_servers,
                                   int nr_irqs)
 {
diff --git a/hw/ppc/spapr_events.c b/hw/ppc/spapr_events.c
index 5ce96a7196..1b6157dec4 100644
--- a/hw/ppc/spapr_events.c
+++ b/hw/ppc/spapr_events.c
@@ -314,7 +314,7 @@ static void check_exception(PowerPCCPU *cpu, sPAPREnvironment *spapr,
 
 void spapr_events_init(sPAPREnvironment *spapr)
 {
-    spapr->epow_irq = spapr_allocate_msi(0);
+    spapr->epow_irq = xics_alloc(spapr->icp, 0, 0, false);
     spapr->epow_notifier.notify = spapr_powerdown_req;
     qemu_register_powerdown_notifier(&spapr->epow_notifier);
     spapr_rtas_register(RTAS_CHECK_EXCEPTION, "check-exception",
diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
index d1e3e0ff10..d115fca31e 100644
--- a/hw/ppc/spapr_pci.c
+++ b/hw/ppc/spapr_pci.c
@@ -360,8 +360,8 @@ static void rtas_ibm_change_msi(PowerPCCPU *cpu, sPAPREnvironment *spapr,
 
     /* There is no cached config, allocate MSIs */
     if (!phb->msi_table[ndev].nvec) {
-        irq = spapr_allocate_irq_block(req_num, false,
-                                       ret_intr_type == RTAS_TYPE_MSI);
+        irq = xics_alloc_block(spapr->icp, 0, req_num, false,
+                               ret_intr_type == RTAS_TYPE_MSI);
         if (irq < 0) {
             error_report("Cannot allocate MSIs for device#%d", ndev);
             rtas_st(rets, 0, RTAS_OUT_HW_ERROR);
@@ -634,7 +634,7 @@ static void spapr_phb_realize(DeviceState *dev, Error **errp)
     for (i = 0; i < PCI_NUM_PINS; i++) {
         uint32_t irq;
 
-        irq = spapr_allocate_lsi(0);
+        irq = xics_alloc_block(spapr->icp, 0, 1, true, false);
         if (!irq) {
             error_setg(errp, "spapr_allocate_lsi failed");
             return;
diff --git a/hw/ppc/spapr_vio.c b/hw/ppc/spapr_vio.c
index 8b765c65e8..dc9e46a7b1 100644
--- a/hw/ppc/spapr_vio.c
+++ b/hw/ppc/spapr_vio.c
@@ -449,7 +449,7 @@ static int spapr_vio_busdev_init(DeviceState *qdev)
         dev->qdev.id = id;
     }
 
-    dev->irq = spapr_allocate_msi(dev->irq);
+    dev->irq = xics_alloc(spapr->icp, 0, dev->irq, false);
     if (!dev->irq) {
         return -1;
     }