[Qemu-devel] [PATCH 09/12] isa: Clean up error handling around isa_bus_new()

[Markus Armbruster <armbru@redhat.com>]

We can have at most one ISA bus.  If you try to create another one,
isa_bus_new() complains to stderr and returns null.

isa_bus_new() is called in two contexts, machine's init() and device's
realize() methods.  Since complaining to stderr is not proper in the
latter context, convert isa_bus_new() to Error.

Machine's init():

* mips_jazz_init(), called from the init() methods of machines
  "magnum" and "pica"

* mips_r4k_init(), the init() method of machine "mips"

* pc_init1() called from the init() methods of non-q35 PC machines

* typhoon_init(), called from clipper_init(), the init() method of
  machine "clipper"

These callers always create the first ISA bus, hence isa_bus_new()
can't fail.  Simply pass &error_abort.

Device's realize():

* i82378_realize(), of PCI device "i82378"

* ich9_lpc_realize(), of PCI device "ICH9-LPC"

* pci_ebus_realize(), of PCI device "ebus"

* piix3_realize(), of PCI device "pci-piix3", abstract parent of
  "PIIX3" and "PIIX3-xen"

* piix4_realize(), of PCI device "PIIX4"

* vt82c686b_realize(), of PCI device "VT82C686B"

Propagate the error.  Note that these devices are typically created
only by machine init() methods with qdev_init_nofail() or similar.  If
we screwed up and created an ISA bus before that call, we now give up
right away.  Before, we'd hobble on, and typically die in
isa_bus_irqs().  Similar if someone finds a way to hot-plug one of
these critters.

Cc: Richard Henderson <rth@twiddle.net>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: "Hervé Poussineau" <hpoussin@reactos.org>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 hw/alpha/typhoon.c   | 3 ++-
 hw/i386/pc_piix.c    | 3 ++-
 hw/isa/i82378.c      | 5 ++++-
 hw/isa/isa-bus.c     | 4 ++--
 hw/isa/lpc_ich9.c    | 6 +++++-
 hw/isa/piix4.c       | 6 ++++--
 hw/isa/vt82c686.c    | 5 ++++-
 hw/mips/mips_jazz.c  | 2 +-
 hw/mips/mips_r4k.c   | 2 +-
 hw/pci-host/piix.c   | 6 ++++--
 hw/sparc64/sun4u.c   | 6 ++++--
 include/hw/isa/isa.h | 2 +-
 12 files changed, 34 insertions(+), 16 deletions(-)

diff --git a/hw/alpha/typhoon.c b/hw/alpha/typhoon.c
index 421162e..35dc8a5 100644
--- a/hw/alpha/typhoon.c
+++ b/hw/alpha/typhoon.c
@@ -920,7 +920,8 @@ PCIBus *typhoon_init(ram_addr_t ram_size, ISABus **isa_bus,
     {
         qemu_irq *isa_irqs;
 
-        *isa_bus = isa_bus_new(NULL, get_system_memory(), &s->pchip.reg_io);
+        *isa_bus = isa_bus_new(NULL, get_system_memory(), &s->pchip.reg_io,
+                               &error_abort);
         isa_irqs = i8259_init(*isa_bus,
                               qemu_allocate_irq(typhoon_set_isa_irq, s, 0));
         isa_bus_irqs(*isa_bus, isa_irqs);
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 2e41efe..48fdad4 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -200,7 +200,8 @@ static void pc_init1(MachineState *machine,
     } else {
         pci_bus = NULL;
         i440fx_state = NULL;
-        isa_bus = isa_bus_new(NULL, get_system_memory(), system_io);
+        isa_bus = isa_bus_new(NULL, get_system_memory(), system_io,
+                              &error_abort);
         no_hpet = 1;
     }
     isa_bus_irqs(isa_bus, gsi);
diff --git a/hw/isa/i82378.c b/hw/isa/i82378.c
index d4c8306..3793c6f 100644
--- a/hw/isa/i82378.c
+++ b/hw/isa/i82378.c
@@ -75,7 +75,10 @@ static void i82378_realize(PCIDevice *pci, Error **errp)
     pci_config_set_interrupt_pin(pci_conf, 1); /* interrupt pin 0 */
 
     isabus = isa_bus_new(dev, get_system_memory(),
-                         pci_address_space_io(pci));
+                         pci_address_space_io(pci), errp);
+    if (!isabus) {
+        return;
+    }
 
     /* This device has:
        2 82C59 (irq)
diff --git a/hw/isa/isa-bus.c b/hw/isa/isa-bus.c
index 43e0cd8..af6ffd6 100644
--- a/hw/isa/isa-bus.c
+++ b/hw/isa/isa-bus.c
@@ -44,10 +44,10 @@ static const TypeInfo isa_bus_info = {
 };
 
 ISABus *isa_bus_new(DeviceState *dev, MemoryRegion* address_space,
-                    MemoryRegion *address_space_io)
+                    MemoryRegion *address_space_io, Error **errp)
 {
     if (isabus) {
-        fprintf(stderr, "Can't create a second ISA bus\n");
+        error_setg(errp, "Can't create a second ISA bus");
         return NULL;
     }
     if (!dev) {
diff --git a/hw/isa/lpc_ich9.c b/hw/isa/lpc_ich9.c
index 8e58449..ed9907d 100644
--- a/hw/isa/lpc_ich9.c
+++ b/hw/isa/lpc_ich9.c
@@ -607,7 +607,11 @@ static void ich9_lpc_realize(PCIDevice *d, Error **errp)
     ICH9LPCState *lpc = ICH9_LPC_DEVICE(d);
     ISABus *isa_bus;
 
-    isa_bus = isa_bus_new(DEVICE(d), get_system_memory(), get_system_io());
+    isa_bus = isa_bus_new(DEVICE(d), get_system_memory(), get_system_io(),
+                          errp);
+    if (!isa_bus) {
+        return;
+    }
 
     pci_set_long(d->wmask + ICH9_LPC_PMBASE,
                  ICH9_LPC_PMBASE_BASE_ADDRESS_MASK);
diff --git a/hw/isa/piix4.c b/hw/isa/piix4.c
index 2c59e91..644cfd9 100644
--- a/hw/isa/piix4.c
+++ b/hw/isa/piix4.c
@@ -90,8 +90,10 @@ static void piix4_realize(PCIDevice *dev, Error **errp)
 {
     PIIX4State *d = PIIX4_PCI_DEVICE(dev);
 
-    isa_bus_new(DEVICE(d), pci_address_space(dev),
-                pci_address_space_io(dev));
+    if (!isa_bus_new(DEVICE(d), pci_address_space(dev),
+                     pci_address_space_io(dev), errp)) {
+        return;
+    }
     piix4_dev = &d->dev;
     qemu_register_reset(piix4_reset, d);
 }
diff --git a/hw/isa/vt82c686.c b/hw/isa/vt82c686.c
index 252e1d7..6c2190b 100644
--- a/hw/isa/vt82c686.c
+++ b/hw/isa/vt82c686.c
@@ -440,7 +440,10 @@ static void vt82c686b_realize(PCIDevice *d, Error **errp)
     int i;
 
     isa_bus = isa_bus_new(DEVICE(d), get_system_memory(),
-                          pci_address_space_io(d));
+                          pci_address_space_io(d), errp);
+    if (!isa_bus) {
+        return;
+    }
 
     pci_conf = d->config;
     pci_config_set_prog_interface(pci_conf, 0x0);
diff --git a/hw/mips/mips_jazz.c b/hw/mips/mips_jazz.c
index 1ab885b..1cfbaa6 100644
--- a/hw/mips/mips_jazz.c
+++ b/hw/mips/mips_jazz.c
@@ -219,7 +219,7 @@ static void mips_jazz_init(MachineState *machine,
     memory_region_init(isa_mem, NULL, "isa-mem", 0x01000000);
     memory_region_add_subregion(address_space, 0x90000000, isa_io);
     memory_region_add_subregion(address_space, 0x91000000, isa_mem);
-    isa_bus = isa_bus_new(NULL, isa_mem, isa_io);
+    isa_bus = isa_bus_new(NULL, isa_mem, isa_io, &error_abort);
 
     /* ISA devices */
     i8259 = i8259_init(isa_bus, env->irq[4]);
diff --git a/hw/mips/mips_r4k.c b/hw/mips/mips_r4k.c
index af10da1..2d4e038 100644
--- a/hw/mips/mips_r4k.c
+++ b/hw/mips/mips_r4k.c
@@ -272,7 +272,7 @@ void mips_r4k_init(MachineState *machine)
     memory_region_init(isa_mem, NULL, "isa-mem", 0x01000000);
     memory_region_add_subregion(get_system_memory(), 0x14000000, isa_io);
     memory_region_add_subregion(get_system_memory(), 0x10000000, isa_mem);
-    isa_bus = isa_bus_new(NULL, isa_mem, get_system_io());
+    isa_bus = isa_bus_new(NULL, isa_mem, get_system_io(), &error_abort);
 
     /* The PIC is attached to the MIPS CPU INT0 pin */
     i8259 = i8259_init(isa_bus, env->irq[2]);
diff --git a/hw/pci-host/piix.c b/hw/pci-host/piix.c
index 715208b..775b4bd 100644
--- a/hw/pci-host/piix.c
+++ b/hw/pci-host/piix.c
@@ -651,8 +651,10 @@ static void piix3_realize(PCIDevice *dev, Error **errp)
 {
     PIIX3State *d = PIIX3_PCI_DEVICE(dev);
 
-    isa_bus_new(DEVICE(d), get_system_memory(),
-                pci_address_space_io(dev));
+    if (!isa_bus_new(DEVICE(d), get_system_memory(),
+                     pci_address_space_io(dev), errp)) {
+        return;
+    }
 
     memory_region_init_io(&d->rcr_mem, OBJECT(dev), &rcr_ops, d,
                           "piix3-reset-control", 1);
diff --git a/hw/sparc64/sun4u.c b/hw/sparc64/sun4u.c
index c37e8b0..6c7596b 100644
--- a/hw/sparc64/sun4u.c
+++ b/hw/sparc64/sun4u.c
@@ -597,8 +597,10 @@ static void pci_ebus_realize(PCIDevice *pci_dev, Error **errp)
 {
     EbusState *s = DO_UPCAST(EbusState, pci_dev, pci_dev);
 
-    isa_bus_new(DEVICE(pci_dev), get_system_memory(),
-                pci_address_space_io(pci_dev));
+    if (!isa_bus_new(DEVICE(pci_dev), get_system_memory(),
+                     pci_address_space_io(pci_dev), errp)) {
+        return;
+    }
 
     pci_dev->config[0x04] = 0x06; // command = bus master, pci mem
     pci_dev->config[0x05] = 0x00;
diff --git a/include/hw/isa/isa.h b/include/hw/isa/isa.h
index d758b39..de3cd3d 100644
--- a/include/hw/isa/isa.h
+++ b/include/hw/isa/isa.h
@@ -59,7 +59,7 @@ struct ISADevice {
 };
 
 ISABus *isa_bus_new(DeviceState *dev, MemoryRegion *address_space,
-                    MemoryRegion *address_space_io);
+                    MemoryRegion *address_space_io, Error **errp);
 void isa_bus_irqs(ISABus *bus, qemu_irq *irqs);
 qemu_irq isa_get_irq(ISADevice *dev, int isairq);
 void isa_init_irq(ISADevice *dev, qemu_irq *p, int isairq);
-- 
2.4.3