Re: [PATCH] hw/ppc/ppc4xx_pci: Fix ppc4xx_pci_map_irq() for recent Linux kernels

[David Gibson <david@gibson.dropbear.id.au>]

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On Tue, Oct 19, 2021 at 11:18:17AM +0200, Thomas Huth wrote:
65;6402;1c> Recent Linux kernels are accessing the PCI device in slot 0 that
> represents the PCI host bridge. This causes ppc4xx_pci_map_irq()
> to return -1 which causes an assert() later:
> 
>  hw/pci/pci.c:262: pci_bus_change_irq_level: Assertion `irq_num >= 0' failed.
> 
> Thus we should allocate an IRQ line for the device in slot 0, too.
> To avoid changes to the outside of ppc4xx_pci.c, we map it to
> the internal IRQ number 4 which will then happily be ignored since
> ppc440_bamboo.c does not wire it up.
> 
> With these changes it is now possible again to use recent Linux
> kernels for the bamboo board.
> 
> Signed-off-by: Thomas Huth <thuth@redhat.com>

Applied to ppc-for-6.2, thanks.

> ---
>  hw/ppc/ppc4xx_pci.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/ppc/ppc4xx_pci.c b/hw/ppc/ppc4xx_pci.c
> index 8147ba6f94..304a29349c 100644
> --- a/hw/ppc/ppc4xx_pci.c
> +++ b/hw/ppc/ppc4xx_pci.c
> @@ -48,12 +48,14 @@ OBJECT_DECLARE_SIMPLE_TYPE(PPC4xxPCIState, PPC4xx_PCI_HOST_BRIDGE)
>  #define PPC4xx_PCI_NR_PMMS 3
>  #define PPC4xx_PCI_NR_PTMS 2
>  
> +#define PPC4xx_PCI_NUM_DEVS 5
> +
>  struct PPC4xxPCIState {
>      PCIHostState parent_obj;
>  
>      struct PCIMasterMap pmm[PPC4xx_PCI_NR_PMMS];
>      struct PCITargetMap ptm[PPC4xx_PCI_NR_PTMS];
> -    qemu_irq irq[PCI_NUM_PINS];
> +    qemu_irq irq[PPC4xx_PCI_NUM_DEVS];
>  
>      MemoryRegion container;
>      MemoryRegion iomem;
> @@ -246,7 +248,7 @@ static int ppc4xx_pci_map_irq(PCIDevice *pci_dev, int irq_num)
>  
>      trace_ppc4xx_pci_map_irq(pci_dev->devfn, irq_num, slot);
>  
> -    return slot - 1;
> +    return slot > 0 ? slot - 1 : PPC4xx_PCI_NUM_DEVS - 1;
>  }
>  
>  static void ppc4xx_pci_set_irq(void *opaque, int irq_num, int level)
> @@ -254,7 +256,7 @@ static void ppc4xx_pci_set_irq(void *opaque, int irq_num, int level)
>      qemu_irq *pci_irqs = opaque;
>  
>      trace_ppc4xx_pci_set_irq(irq_num);
> -    assert(irq_num >= 0);
> +    assert(irq_num >= 0 && irq_num < PPC4xx_PCI_NUM_DEVS);
>      qemu_set_irq(pci_irqs[irq_num], level);
>  }
>  

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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