pseries: Rework irq assignment to avoid carrying qemu_irqs around

Currently, the interfaces in the pseries machine code for assignment
and setup of interrupts pass around qemu_irq objects.  That was done
in an attempt not to be too closely linked to the specific XICS
interrupt controller.  However interactions with the device tree setup
made that attempt rather futile, and XICS is part of the PAPR spec
anyway, so this really just meant we had to carry both the qemu_irq
pointers and the XICS irq numbers around.

This mess will just get worse when we add upcoming PCI MSI support,
since that will require tracking a bunch more interrupt.  Therefore,
this patch reworks the spapr code to just use XICS irq numbers
(roughly equivalent to GSIs on x86) and only retrieve the qemu_irq
pointers from the XICS code when we need them (a trivial lookup).

This is a reworked and generalized version of an earlier spapr_pci
specific patch from Alexey Kardashevskiy.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
[agraf: fix checkpath warning]
Signed-off-by: Alexander Graf <agraf@suse.de>

hw/spapr.c

@@ -84,11 +84,9 @@
 
 sPAPREnvironment *spapr;
 
-qemu_irq spapr_allocate_irq(uint32_t hint, uint32_t *irq_num,
-                            enum xics_irq_type type)
+int spapr_allocate_irq(int hint, enum xics_irq_type type)
 {
-    uint32_t irq;
-    qemu_irq qirq;
+    int irq;
 
     if (hint) {
         irq = hint;
@@ -97,16 +95,14 @@ qemu_irq spapr_allocate_irq(uint32_t hint, uint32_t *irq_num,
         irq = spapr->next_irq++;
     }
 
-    qirq = xics_assign_irq(spapr->icp, irq, type);
-    if (!qirq) {
-        return NULL;
+    /* Configure irq type */
+    if (!xics_get_qirq(spapr->icp, irq)) {
+        return 0;
     }
 
-    if (irq_num) {
-        *irq_num = irq;
-    }
+    xics_set_irq_type(spapr->icp, irq, type);
 
-    return qirq;
+    return irq;
 }
 
 static int spapr_set_associativity(void *fdt, sPAPREnvironment *spapr)

hw/spapr.h

@@ -289,17 +289,16 @@ void spapr_register_hypercall(target_ulong opcode, spapr_hcall_fn fn);
 target_ulong spapr_hypercall(CPUPPCState *env, target_ulong opcode,
                              target_ulong *args);
 
-qemu_irq spapr_allocate_irq(uint32_t hint, uint32_t *irq_num,
-                            enum xics_irq_type type);
+int spapr_allocate_irq(int hint, enum xics_irq_type type);
 
-static inline qemu_irq spapr_allocate_msi(uint32_t hint, uint32_t *irq_num)
+static inline int spapr_allocate_msi(int hint)
 {
-    return spapr_allocate_irq(hint, irq_num, XICS_MSI);
+    return spapr_allocate_irq(hint, XICS_MSI);
 }
 
-static inline qemu_irq spapr_allocate_lsi(uint32_t hint, uint32_t *irq_num)
+static inline int spapr_allocate_lsi(int hint)
 {
-    return spapr_allocate_irq(hint, irq_num, XICS_LSI);
+    return spapr_allocate_irq(hint, XICS_LSI);
 }
 
 static inline uint32_t rtas_ld(target_ulong phys, int n)

hw/spapr_llan.c

@@ -169,7 +169,7 @@ static ssize_t spapr_vlan_receive(NetClientState *nc, const uint8_t *buf,
     }
 
     if (sdev->signal_state & 1) {
-        qemu_irq_pulse(sdev->qirq);
+        qemu_irq_pulse(spapr_vio_qirq(sdev));
     }
 
     return size;

hw/spapr_pci.c

@@ -223,7 +223,7 @@ static void pci_spapr_set_irq(void *opaque, int irq_num, int level)
      */
     sPAPRPHBState *phb = opaque;
 
-    qemu_set_irq(phb->lsi_table[irq_num].qirq, level);
+    qemu_set_irq(spapr_phb_lsi_qirq(phb, irq_num), level);
 }
 
 static uint64_t spapr_io_read(void *opaque, target_phys_addr_t addr,
@@ -329,16 +329,14 @@ static int spapr_phb_init(SysBusDevice *s)
 
     /* Initialize the LSI table */
     for (i = 0; i < PCI_NUM_PINS; i++) {
-        qemu_irq qirq;
-        uint32_t num;
+        uint32_t irq;
 
-        qirq = spapr_allocate_lsi(0, &num);
-        if (!qirq) {
+        irq = spapr_allocate_lsi(0);
+        if (!irq) {
             return -1;
         }
 
-        phb->lsi_table[i].dt_irq = num;
-        phb->lsi_table[i].qirq = qirq;
+        phb->lsi_table[i].irq = irq;
     }
 
     return 0;
@@ -477,7 +475,7 @@ int spapr_populate_pci_dt(sPAPRPHBState *phb,
             irqmap[2] = 0;
             irqmap[3] = cpu_to_be32(j+1);
             irqmap[4] = cpu_to_be32(xics_phandle);
-            irqmap[5] = cpu_to_be32(phb->lsi_table[lsi_num].dt_irq);
+            irqmap[5] = cpu_to_be32(phb->lsi_table[lsi_num].irq);
             irqmap[6] = cpu_to_be32(0x8);
         }
     }

hw/spapr_pci.h

@@ -40,13 +40,17 @@ typedef struct sPAPRPHBState {
     DMAContext *dma;
 
     struct {
-        uint32_t dt_irq;
-        qemu_irq qirq;
+        uint32_t irq;
     } lsi_table[PCI_NUM_PINS];
 
     QLIST_ENTRY(sPAPRPHBState) list;
 } sPAPRPHBState;
 
+static inline qemu_irq spapr_phb_lsi_qirq(struct sPAPRPHBState *phb, int pin)
+{
+    return xics_get_qirq(spapr->icp, phb->lsi_table[pin].irq);
+}
+
 #define SPAPR_PCI_MEM_WIN_BUS_OFFSET 0x80000000ULL
 #define SPAPR_PCI_IO_WIN_SIZE        0x10000
 

hw/spapr_vio.c

@@ -49,7 +49,7 @@
 #endif
 
 static Property spapr_vio_props[] = {
-    DEFINE_PROP_UINT32("irq", VIOsPAPRDevice, vio_irq_num, 0), \
+    DEFINE_PROP_UINT32("irq", VIOsPAPRDevice, irq, 0), \
     DEFINE_PROP_END_OF_LIST(),
 };
 
@@ -132,8 +132,8 @@ static int vio_make_devnode(VIOsPAPRDevice *dev,
         }
     }
 
-    if (dev->qirq) {
-        uint32_t ints_prop[] = {cpu_to_be32(dev->vio_irq_num), 0};
+    if (dev->irq) {
+        uint32_t ints_prop[] = {cpu_to_be32(dev->irq), 0};
 
         ret = fdt_setprop(fdt, node_off, "interrupts", ints_prop,
                           sizeof(ints_prop));
@@ -306,7 +306,7 @@ int spapr_vio_send_crq(VIOsPAPRDevice *dev, uint8_t *crq)
     dev->crq.qnext = (dev->crq.qnext + 16) % dev->crq.qsize;
 
     if (dev->signal_state & 1) {
-        qemu_irq_pulse(dev->qirq);
+        qemu_irq_pulse(spapr_vio_qirq(dev));
     }
 
     return 0;
@@ -459,8 +459,8 @@ static int spapr_vio_busdev_init(DeviceState *qdev)
         dev->qdev.id = id;
     }
 
-    dev->qirq = spapr_allocate_msi(dev->vio_irq_num, &dev->vio_irq_num);
-    if (!dev->qirq) {
+    dev->irq = spapr_allocate_msi(dev->irq);
+    if (!dev->irq) {
         return -1;
     }
 

hw/spapr_vio.h

@@ -61,8 +61,7 @@ struct VIOsPAPRDevice {
     DeviceState qdev;
     uint32_t reg;
     uint32_t flags;
-    qemu_irq qirq;
-    uint32_t vio_irq_num;
+    uint32_t irq;
     target_ulong signal_state;
     VIOsPAPR_CRQ crq;
     DMAContext *dma;
@@ -85,6 +84,11 @@ extern int spapr_populate_chosen_stdout(void *fdt, VIOsPAPRBus *bus);
 
 extern int spapr_vio_signal(VIOsPAPRDevice *dev, target_ulong mode);
 
+static inline qemu_irq spapr_vio_qirq(VIOsPAPRDevice *dev)
+{
+    return xics_get_qirq(spapr->icp, dev->irq);
+}
+
 static inline bool spapr_vio_dma_valid(VIOsPAPRDevice *dev, uint64_t taddr,
                                        uint32_t size, DMADirection dir)
 {

hw/spapr_vty.c

@@ -26,7 +26,7 @@ static void vty_receive(void *opaque, const uint8_t *buf, int size)
 
     if ((dev->in == dev->out) && size) {
         /* toggle line to simulate edge interrupt */
-        qemu_irq_pulse(dev->sdev.qirq);
+        qemu_irq_pulse(spapr_vio_qirq(&dev->sdev));
     }
     for (i = 0; i < size; i++) {
         assert((dev->in - dev->out) < VTERM_BUFSIZE);

hw/xics.c

@@ -315,18 +315,24 @@ static void ics_eoi(struct ics_state *ics, int nr)
  * Exported functions
  */
 
-qemu_irq xics_assign_irq(struct icp_state *icp, int irq,
-                         enum xics_irq_type type)
+qemu_irq xics_get_qirq(struct icp_state *icp, int irq)
 {
     if ((irq < icp->ics->offset)
         || (irq >= (icp->ics->offset + icp->ics->nr_irqs))) {
         return NULL;
     }
 
+    return icp->ics->qirqs[irq - icp->ics->offset];
+}
+
+void xics_set_irq_type(struct icp_state *icp, int irq,
+                       enum xics_irq_type type)
+{
+    assert((irq >= icp->ics->offset)
+           && (irq < (icp->ics->offset + icp->ics->nr_irqs)));
     assert((type == XICS_MSI) || (type == XICS_LSI));
 
     icp->ics->irqs[irq - icp->ics->offset].type = type;
-    return icp->ics->qirqs[irq - icp->ics->offset];
 }
 
 static target_ulong h_cppr(CPUPPCState *env, sPAPREnvironment *spapr,

hw/xics.h

@@ -36,8 +36,9 @@ enum xics_irq_type {
     XICS_LSI,        /* Level-signalled interrupt */
 };
 
-qemu_irq xics_assign_irq(struct icp_state *icp, int irq,
-                         enum xics_irq_type type);
+qemu_irq xics_get_qirq(struct icp_state *icp, int irq);
+void xics_set_irq_type(struct icp_state *icp, int irq,
+                       enum xics_irq_type type);
 
 struct icp_state *xics_system_init(int nr_irqs);