Re: [Qemu-devel] [PATCH] pc: pcihp: avoid adding ACPI_PCIHP_PROP_BSEL twice

[Marcel Apfelbaum]

On 08/03/2016 11:04 AM, Igor Mammedov wrote:
> PCI hotplug for bridges was introduced only since 2.0 however
>   acpi_set_bsel()->object_property_add_uint32_ptr(bus, ACPI_PCIHP_PROP_BSEL)
> didn't take in account that for legacy mode (1.7) when
> PCI hotplug for bridges is unavailable and ACPI_PCIHP_PROP_BSEL property
> the only bus "PCI.0' has been created earlier at acpi_pcihp_init() time.
>
> We managed to live with it only because of error rised by adding
> a duplicate property in acpi_set_bsel() has been ignored which
> resulted in useless leaking of just allocated (int)bus_bsel.
>
> Issue affects only 1.7 machine type as ACPI tables supported by
> QEMU were introduced at that time, but there wasn't PCI hotplug
> for bridges till the next release (2.0).
>
> Fix it by removing duplicate ACPI_PCIHP_PROP_BSEL intialization
> in acpi_pcihp_init() and doing it only in one place acpi_set_pci_info().
>
> PS:
> do not ignore error returned by object_property_add_uint32_ptr()
> and abort QEMU since it's programming error which should be fixed
> instead of being ignored.
>
> Signed-off-by: Igor Mammedov <address@hidden>
> Reported-by: Marc-André Lureau <address@hidden>
> ---
>  hw/acpi/pcihp.c      | 10 ----------
>  hw/i386/acpi-build.c |  4 ++--
>  2 files changed, 2 insertions(+), 12 deletions(-)
>
> diff --git a/hw/acpi/pcihp.c b/hw/acpi/pcihp.c
> index d957d1e..3298d94 100644
> --- a/hw/acpi/pcihp.c
> +++ b/hw/acpi/pcihp.c
> @@ -302,16 +302,6 @@ void acpi_pcihp_init(Object *owner, AcpiPciHpState *s, 
> PCIBus *root_bus,
>      s->root= root_bus;
>      s->legacy_piix = !bridges_enabled;
>
> -    if (s->legacy_piix) {
> -        unsigned *bus_bsel = g_malloc(sizeof *bus_bsel);
> -
> -        s->io_len = ACPI_PCIHP_LEGACY_SIZE;
> -
> -        *bus_bsel = ACPI_PCIHP_BSEL_DEFAULT;
> -        object_property_add_uint32_ptr(OBJECT(root_bus), ACPI_PCIHP_PROP_BSEL,
> -                                       bus_bsel, NULL);
> -    }
> -
>      memory_region_init_io(&s->io, owner, &acpi_pcihp_io_ops, s,
>                            "acpi-pci-hotplug", s->io_len);
>      memory_region_add_subregion(address_space_io, s->io_base, &s->io);
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index a26a4bb..7174933 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -438,7 +438,7 @@ static void *acpi_set_bsel(PCIBus *bus, void *opaque)
>
>          *bus_bsel = (*bsel_alloc)++;
>          object_property_add_uint32_ptr(OBJECT(bus), ACPI_PCIHP_PROP_BSEL,
> -                                       bus_bsel, NULL);
> +                                       bus_bsel, &error_abort);

Hi Igor,

I think the above hunk should be in a separate patch, but
since the patch itself is small enough I am OK with it.


>      }
>
>      return bsel_alloc;
> @@ -447,7 +447,7 @@ static void *acpi_set_bsel(PCIBus *bus, void *opaque)
>  static void acpi_set_pci_info(void)
>  {
>      PCIBus *bus = find_i440fx(); /* TODO: Q35 support */
> -    unsigned bsel_alloc = 0;
> +    unsigned bsel_alloc = ACPI_PCIHP_BSEL_DEFAULT;
>
>      if (bus) {
>          /* Scan all PCI buses. Set property to enable acpi based hotplug. */



Reviewed-by: Marcel Apfelbaum <address@hidden>

Thanks,
Marcel