[Qemu-devel] [PATCH 6/8] spapr: move interrupt allocator to xics

[Alexey Kardashevskiy <aik@ozlabs.ru>]

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 had the last returned IRQ.
However migration may change interrupts for devices depending on
their order in the command line.

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 in use.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 hw/intc/xics.c         | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++
 hw/ppc/spapr.c         | 67 ------------------------------------------
 hw/ppc/spapr_events.c  |  2 +-
 hw/ppc/spapr_pci.c     |  6 ++--
 hw/ppc/spapr_vio.c     |  2 +-
 include/hw/ppc/spapr.h | 10 -------
 include/hw/ppc/xics.h  |  2 ++
 trace-events           |  3 ++
 8 files changed, 90 insertions(+), 82 deletions(-)

diff --git a/hw/intc/xics.c b/hw/intc/xics.c
index e5195bf..8d101a3 100644
--- a/hw/intc/xics.c
+++ b/hw/intc/xics.c
@@ -690,6 +690,86 @@ void xics_set_irq_type(XICSState *icp, int irq, bool lsi)
     ics_set_irq_type(&icp->ics[server], irq, lsi);
 }
 
+#define XICS_IRQ_FREE(ics, n)   \
+    (!((ics)->irqs[(n) - (ics)->offset].flags & \
+       (XICS_FLAGS_LSI | XICS_FLAGS_MSI)))
+
+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 (!XICS_IRQ_FREE(ics, i + ics->offset)) {
+                break;
+            }
+        }
+        if (i == (first + num)) {
+            return first + ics->offset;
+        }
+    }
+
+    return -1;
+}
+
+int xics_alloc(XICSState *icp, int server, int irq, bool lsi)
+{
+    ICSState *ics = &icp->ics[server];
+
+    if (irq) {
+        assert(server == xics_find_server(icp, irq));
+        if (!XICS_IRQ_FREE(ics, irq)) {
+            trace_xics_alloc_failed(server, irq);
+            return -1;
+        }
+    } else {
+        irq = ics_find_free_block(ics, 1, 1);
+    }
+
+    ics_set_irq_type(ics, irq, lsi);
+    trace_xics_alloc(server, 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 server, int num, bool lsi, bool align)
+{
+    int i, first = -1;
+    ICSState *ics = &icp->ics[server];
+
+    assert(server == 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);
+        }
+    }
+    trace_xics_alloc_block(server, first, num, lsi, align);
+
+    return first;
+}
+
 /*
  * Guest interfaces
  */
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 12adc21..29ca2e0 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -83,73 +83,6 @@
 
 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 16fa49e..e605430 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_block(spapr->icp, 0, 1, false, false);
     spapr->epow_notifier.notify = spapr_powerdown_req;
     qemu_register_powerdown_notifier(&spapr->epow_notifier);
     spapr_rtas_register("check-exception", check_exception);
diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
index cbef095..4eaf364 100644
--- a/hw/ppc/spapr_pci.c
+++ b/hw/ppc/spapr_pci.c
@@ -343,8 +343,8 @@ 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);
@@ -623,7 +623,7 @@ 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 4e33f46..8aeb263 100644
--- a/hw/ppc/spapr_vio.c
+++ b/hw/ppc/spapr_vio.c
@@ -448,7 +448,7 @@ 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;
     }
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index 18332fd..5d577ff 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -323,16 +323,6 @@ target_ulong spapr_hypercall(PowerPCCPU *cpu, target_ulong opcode,
 int spapr_allocate_irq(int hint, bool lsi);
 int spapr_allocate_irq_block(int num, bool lsi, bool msi);
 
-static inline int spapr_allocate_msi(int hint)
-{
-    return spapr_allocate_irq(hint, false);
-}
-
-static inline int spapr_allocate_lsi(int hint)
-{
-    return spapr_allocate_irq(hint, true);
-}
-
 /* RTAS return codes */
 #define RTAS_OUT_SUCCESS            0
 #define RTAS_OUT_NO_ERRORS_FOUND    1
diff --git a/include/hw/ppc/xics.h b/include/hw/ppc/xics.h
index 4b30e9a..337398d 100644
--- a/include/hw/ppc/xics.h
+++ b/include/hw/ppc/xics.h
@@ -157,6 +157,8 @@ struct ICSIRQState {
 
 qemu_irq xics_get_qirq(XICSState *icp, int irq);
 void xics_set_irq_type(XICSState *icp, int irq, bool lsi);
+int xics_alloc(XICSState *icp, int server, int irq, bool lsi);
+int xics_alloc_block(XICSState *icp, int server, int num, bool lsi, bool align);
 
 void xics_cpu_setup(XICSState *icp, PowerPCCPU *cpu);
 
diff --git a/trace-events b/trace-events
index 002c260..ad7400e 100644
--- a/trace-events
+++ b/trace-events
@@ -1143,6 +1143,9 @@ xics_set_irq_lsi(int srcno, int nr) "set_irq_lsi: srcno %d [irq %#x]"
 xics_ics_write_xive(int nr, int srcno, int server, uint8_t priority) "ics_write_xive: irq %#x [src %d] server %#x prio %#x"
 xics_ics_reject(int nr, int srcno) "reject irq %#x [src %d]"
 xics_ics_eoi(int nr) "ics_eoi: irq %#x"
+xics_alloc(int server, int irq) "server#%d, irq %d"
+xics_alloc_failed(int server, int irq) "server#%d, irq %d"
+xics_alloc_block(int server, int first, int num, bool lsi, int align) "server#%d, first irq %d, %d irqs, lsi=%d, alignnum %d"
 
 # hw/ppc/spapr_iommu.c
 spapr_iommu_put(uint64_t liobn, uint64_t ioba, uint64_t tce, uint64_t ret) "liobn=%"PRIx64" ioba=0x%"PRIx64" tce=0x%"PRIx64" ret=%"PRId64
-- 
1.8.4.rc4