xics: Add flags for interrupts

The existing interrupt allocation scheme in SPAPR assumes that
interrupts are allocated at the start time, continously and the config
will not change. However, there are cases when this is not going to work
such as:

1. migration - we will have to have an ability to choose interrupt
numbers for devices in the command line and this will create gaps in
interrupt space.

2. PCI hotplug - interrupts from unplugged device need to be returned
back to interrupt pool, otherwise we will quickly run out of interrupts.

This replaces a separate lslsi[] array with a byte in the ICSIRQState
struct and defines "LSI" and "MSI" flags. Neither of these flags set
signals that the descriptor is not allocated and not in use.

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

2 files changed, 20 insertions, 11 deletions

diff --git a/hw/intc/xics.c b/hw/intc/xics.c
index 493a2a4..5220d4f 100644
--- a/hw/intc/xics.c
+++ b/hw/intc/xics.c
@@ -437,7 +437,7 @@ static void ics_set_irq(void *opaque, int srcno, int val)
 {
     ICSState *ics = (ICSState *)opaque;
 
-    if (ics->islsi[srcno]) {
+    if (ics->irqs[srcno].flags & XICS_FLAGS_IRQ_LSI) {
         set_irq_lsi(ics, srcno, val);
     } else {
         set_irq_msi(ics, srcno, val);
@@ -474,7 +474,7 @@ static void ics_write_xive(ICSState *ics, int nr, int server,
 
     trace_xics_ics_write_xive(nr, srcno, server, priority);
 
-    if (ics->islsi[srcno]) {
+    if (ics->irqs[srcno].flags & XICS_FLAGS_IRQ_LSI) {
         write_xive_lsi(ics, srcno);
     } else {
         write_xive_msi(ics, srcno);
@@ -496,7 +496,7 @@ static void ics_resend(ICSState *ics)
 
     for (i = 0; i < ics->nr_irqs; i++) {
         /* FIXME: filter by server#? */
-        if (ics->islsi[i]) {
+        if (ics->irqs[i].flags & XICS_FLAGS_IRQ_LSI) {
             resend_lsi(ics, i);
         } else {
             resend_msi(ics, i);
@@ -511,7 +511,7 @@ static void ics_eoi(ICSState *ics, int nr)
 
     trace_xics_ics_eoi(nr);
 
-    if (ics->islsi[srcno]) {
+    if (ics->irqs[srcno].flags & XICS_FLAGS_IRQ_LSI) {
         irq->status &= ~XICS_STATUS_SENT;
     }
 }
@@ -563,13 +563,14 @@ static int ics_dispatch_post_load(void *opaque, int version_id)
 
 static const VMStateDescription vmstate_ics_irq = {
     .name = "ics/irq",
-    .version_id = 1,
+    .version_id = 2,
     .minimum_version_id = 1,
     .fields = (VMStateField[]) {
         VMSTATE_UINT32(server, ICSIRQState),
         VMSTATE_UINT8(priority, ICSIRQState),
         VMSTATE_UINT8(saved_priority, ICSIRQState),
         VMSTATE_UINT8(status, ICSIRQState),
+        VMSTATE_UINT8(flags, ICSIRQState),
         VMSTATE_END_OF_LIST()
     },
 };
@@ -606,7 +607,6 @@ static void ics_realize(DeviceState *dev, Error **errp)
         return;
     }
     ics->irqs = g_malloc0(ics->nr_irqs * sizeof(ICSIRQState));
-    ics->islsi = g_malloc0(ics->nr_irqs * sizeof(bool));
     ics->qirqs = qemu_allocate_irqs(ics_set_irq, ics, ics->nr_irqs);
 }
 
@@ -643,11 +643,21 @@ qemu_irq xics_get_qirq(XICSState *icp, int irq)
     return icp->ics->qirqs[irq - icp->ics->offset];
 }
 
+static void ics_set_irq_type(ICSState *ics, int srcno, bool lsi)
+{
+    assert(!(ics->irqs[srcno].flags & XICS_FLAGS_IRQ_MASK));
+
+    ics->irqs[srcno].flags |=
+        lsi ? XICS_FLAGS_IRQ_LSI : XICS_FLAGS_IRQ_MSI;
+}
+
 void xics_set_irq_type(XICSState *icp, int irq, bool lsi)
 {
-    assert(ics_valid_irq(icp->ics, irq));
+    ICSState *ics = icp->ics;
+
+    assert(ics_valid_irq(ics, irq));
 
-    icp->ics->islsi[irq - icp->ics->offset] = lsi;
+    ics_set_irq_type(ics, irq - ics->offset, lsi);
 }
 
 /*
diff --git a/hw/intc/xics_kvm.c b/hw/intc/xics_kvm.c
index 4704c98..5461454 100644
--- a/hw/intc/xics_kvm.c
+++ b/hw/intc/xics_kvm.c
@@ -220,7 +220,7 @@ static int ics_set_kvm_state(ICSState *ics, int version_id)
             state |= KVM_XICS_MASKED;
         }
 
-        if (ics->islsi[i]) {
+        if (ics->irqs[i].flags & XICS_FLAGS_IRQ_LSI) {
             state |= KVM_XICS_LEVEL_SENSITIVE;
             if (irq->status & XICS_STATUS_ASSERTED) {
                 state |= KVM_XICS_PENDING;
@@ -249,7 +249,7 @@ static void ics_kvm_set_irq(void *opaque, int srcno, int val)
     int rc;
 
     args.irq = srcno + ics->offset;
-    if (!ics->islsi[srcno]) {
+    if (ics->irqs[srcno].flags & XICS_FLAGS_IRQ_MSI) {
         if (!val) {
             return;
         }
@@ -286,7 +286,6 @@ static void ics_kvm_realize(DeviceState *dev, Error **errp)
         return;
     }
     ics->irqs = g_malloc0(ics->nr_irqs * sizeof(ICSIRQState));
-    ics->islsi = g_malloc0(ics->nr_irqs * sizeof(bool));
     ics->qirqs = qemu_allocate_irqs(ics_kvm_set_irq, ics, ics->nr_irqs);
 }