Re: [Xen-devel] [PATCH for-2.10 v3 2/3] hw/acpi: Move acpi_set_pci_info to pcihp

["Michael S. Tsirkin" <mst@xxxxxxxxxx>]

On Thu, Aug 17, 2017 at 05:23:46PM +0100, Anthony PERARD wrote:
> This means that the function will be call and the property
> acpi-pcihp-bsel will be set even if ACPI build is disable.
> 
> To do PCI passthrough with Xen, the property acpi-pcihp-bsel needs to be
> set, but this was done only when ACPI tables are built which is not
> needed for a Xen guest. The need for the property starts with commit
> "pc: pcihp: avoid adding ACPI_PCIHP_PROP_BSEL twice"
> (f0c9d64a68b776374ec4732424a3e27753ce37b6).
> 
> Reported-by: Sander Eikelenboom <linux@xxxxxxxxxxxxxx>
> Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
> 
> ---
> Changes in V3:
>   - move acpi_set_pci_info to pcihp instead
> 
> Changes in V2:
>   - check for acpi_enabled before calling acpi_set_pci_info.
>   - set the property on the root bus only.
> 
> This patch would be a canditade to backport to 2.9, along with
> "hw/acpi: Limit hotplug to root bus on legacy mode"
> 
> CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> CC: Bruce Rogers <brogers@xxxxxxxx>
> ---
>  hw/acpi/pcihp.c      | 31 +++++++++++++++++++++++++++++++
>  hw/i386/acpi-build.c | 32 --------------------------------
>  2 files changed, 31 insertions(+), 32 deletions(-)
> 
> diff --git a/hw/acpi/pcihp.c b/hw/acpi/pcihp.c
> index 9db3c2eaf2..44e8842db8 100644
> --- a/hw/acpi/pcihp.c
> +++ b/hw/acpi/pcihp.c
> @@ -75,6 +75,36 @@ static int acpi_pcihp_get_bsel(PCIBus *bus)
>      }
>  }
>  
> +/* Assign BSEL property to all buses.  In the future, this can be changed
> + * to only assign to buses that support hotplug.
> + */
> +static void *acpi_set_bsel(PCIBus *bus, void *opaque)
> +{
> +    unsigned *bsel_alloc = opaque;
> +    unsigned *bus_bsel;
> +
> +    if (qbus_is_hotpluggable(BUS(bus))) {
> +        bus_bsel = g_malloc(sizeof *bus_bsel);
> +
> +        *bus_bsel = (*bsel_alloc)++;
> +        object_property_add_uint32_ptr(OBJECT(bus), ACPI_PCIHP_PROP_BSEL,
> +                                       bus_bsel, &error_abort);
> +    }
> +
> +    return bsel_alloc;
> +}
> +
> +static void acpi_set_pci_info(void)
> +{
> +    PCIBus *bus = find_i440fx(); /* TODO: Q35 support */
> +    unsigned bsel_alloc = ACPI_PCIHP_BSEL_DEFAULT;
> +
> +    if (bus) {
> +        /* Scan all PCI buses. Set property to enable acpi based hotplug. */
> +        pci_for_each_bus_depth_first(bus, acpi_set_bsel, NULL, &bsel_alloc);
> +    }
> +}
> +
>  static void acpi_pcihp_test_hotplug_bus(PCIBus *bus, void *opaque)
>  {
>      AcpiPciHpFind *find = opaque;
> @@ -177,6 +207,7 @@ static void acpi_pcihp_update(AcpiPciHpState *s)
>  
>  void acpi_pcihp_reset(AcpiPciHpState *s)
>  {
> +    acpi_set_pci_info();
>      acpi_pcihp_update(s);
>  }

IIUC doing this on reset will add property over and over again leaking
memory.

I think that we need to do it on machine done.

Igor,  I think reordering acpi-build like earlier version did
is less intrusive and more appropriate for 2.10.

For 2.10 I would like to see ideally some changes that
are all if (xen) making it obvious non xen is not
affected. I can then ack it and it will be merged in xen tree.


Clean it up after 2.10.

>  
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index 98dd424678..4d19d91e1b 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -493,36 +493,6 @@ build_madt(GArray *table_data, BIOSLinker *linker, 
> PCMachineState *pcms)
>                   table_data->len - madt_start, 1, NULL, NULL);
>  }
>  
> -/* Assign BSEL property to all buses.  In the future, this can be changed
> - * to only assign to buses that support hotplug.
> - */
> -static void *acpi_set_bsel(PCIBus *bus, void *opaque)
> -{
> -    unsigned *bsel_alloc = opaque;
> -    unsigned *bus_bsel;
> -
> -    if (qbus_is_hotpluggable(BUS(bus))) {
> -        bus_bsel = g_malloc(sizeof *bus_bsel);
> -
> -        *bus_bsel = (*bsel_alloc)++;
> -        object_property_add_uint32_ptr(OBJECT(bus), ACPI_PCIHP_PROP_BSEL,
> -                                       bus_bsel, &error_abort);
> -    }
> -
> -    return bsel_alloc;
> -}
> -
> -static void acpi_set_pci_info(void)
> -{
> -    PCIBus *bus = find_i440fx(); /* TODO: Q35 support */
> -    unsigned bsel_alloc = ACPI_PCIHP_BSEL_DEFAULT;
> -
> -    if (bus) {
> -        /* Scan all PCI buses. Set property to enable acpi based hotplug. */
> -        pci_for_each_bus_depth_first(bus, acpi_set_bsel, NULL, &bsel_alloc);
> -    }
> -}
> -
>  static void build_append_pcihp_notify_entry(Aml *method, int slot)
>  {
>      Aml *if_ctx;
> @@ -2888,8 +2858,6 @@ void acpi_setup(void)
>  
>      build_state = g_malloc0(sizeof *build_state);
>  
> -    acpi_set_pci_info();
> -
>      acpi_build_tables_init(&tables);
>      acpi_build(&tables, MACHINE(pcms));
>  
> -- 
> Anthony PERARD

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