Re: [Qemu-devel] [PATCH v2 10/13] isa: Clean up error handling around isa_bus_new()

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Dec 17, 2015 at 01:19:52PM +0100, Markus Armbruster wrote:
> 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@pond.sub.org>
> Reviewed-by: Marcel Apfelbaum <marcel@redhat.com>
> Reviewed-by: Hervé Poussineau <hpoussin@reactos.org>

Reviewed-by: Michael S. Tsirkin <mst@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