Re: [Qemu-devel] [PATCH] PPC: Pseries: Check for PCI boundaries

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

On Wed, Jan 18, 2012 at 05:24:50PM +0100, Alexander Graf wrote:
> We call pci_host_config_{read,write}_common() which perform PCI config
> accesses. However they don't do all limit checking the way we expect
> it to.
> 
> So let's introduce a small wrapper around them, making them behave the
> way we would without touching generic code.
> 
> This patch is based on a patch by David Gibson which put this logic into
> the generic code.
> 
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> Signed-off-by: Alexander Graf <agraf@suse.de>

Nod. Looks like a sensible way to fix pseries without
bothering about breaking other arches.

> ---
>  hw/spapr_pci.c |   27 +++++++++++++++++++++++----
>  1 files changed, 23 insertions(+), 4 deletions(-)
> 
> diff --git a/hw/spapr_pci.c b/hw/spapr_pci.c
> index cf37628..2c95faa 100644
> --- a/hw/spapr_pci.c
> +++ b/hw/spapr_pci.c
> @@ -67,6 +67,25 @@ static uint32_t rtas_pci_cfgaddr(uint32_t arg)
>      return ((arg >> 20) & 0xf00) | (arg & 0xff);
>  }
>  
> +static uint32_t rtas_read_pci_config_do(PCIDevice *pci_dev, uint32_t addr,
> +                                        uint32_t limit, uint32_t len)
> +{
> +    if ((addr + len) <= limit) {
> +        return pci_host_config_read_common(pci_dev, addr, limit, len);
> +    } else {
> +        return ~0x0;
> +    }
> +}
> +
> +static void rtas_write_pci_config_do(PCIDevice *pci_dev, uint32_t addr,
> +                                     uint32_t limit, uint32_t val,
> +                                     uint32_t len)
> +{
> +    if ((addr + len) <= limit) {
> +        pci_host_config_write_common(pci_dev, addr, limit, val, len);
> +    }
> +}
> +
>  static void rtas_ibm_read_pci_config(sPAPREnvironment *spapr,
>                                       uint32_t token, uint32_t nargs,
>                                       target_ulong args,
> @@ -82,7 +101,7 @@ static void rtas_ibm_read_pci_config(sPAPREnvironment *spapr,
>      }
>      size = rtas_ld(args, 3);
>      addr = rtas_pci_cfgaddr(rtas_ld(args, 0));
> -    val = pci_host_config_read_common(dev, addr, pci_config_size(dev), size);
> +    val = rtas_read_pci_config_do(dev, addr, pci_config_size(dev), size);
>      rtas_st(rets, 0, 0);
>      rtas_st(rets, 1, val);
>  }
> @@ -101,7 +120,7 @@ static void rtas_read_pci_config(sPAPREnvironment *spapr,
>      }
>      size = rtas_ld(args, 1);
>      addr = rtas_pci_cfgaddr(rtas_ld(args, 0));
> -    val = pci_host_config_read_common(dev, addr, pci_config_size(dev), size);
> +    val = rtas_read_pci_config_do(dev, addr, pci_config_size(dev), size);
>      rtas_st(rets, 0, 0);
>      rtas_st(rets, 1, val);
>  }
> @@ -122,7 +141,7 @@ static void rtas_ibm_write_pci_config(sPAPREnvironment *spapr,
>      val = rtas_ld(args, 4);
>      size = rtas_ld(args, 3);
>      addr = rtas_pci_cfgaddr(rtas_ld(args, 0));
> -    pci_host_config_write_common(dev, addr, pci_config_size(dev), val, size);
> +    rtas_write_pci_config_do(dev, addr, pci_config_size(dev), val, size);
>      rtas_st(rets, 0, 0);
>  }
>  
> @@ -141,7 +160,7 @@ static void rtas_write_pci_config(sPAPREnvironment *spapr,
>      val = rtas_ld(args, 2);
>      size = rtas_ld(args, 1);
>      addr = rtas_pci_cfgaddr(rtas_ld(args, 0));
> -    pci_host_config_write_common(dev, addr, pci_config_size(dev), val, size);
> +    rtas_write_pci_config_do(dev, addr, pci_config_size(dev), val, size);
>      rtas_st(rets, 0, 0);
>  }
>  
> -- 
> 1.6.0.2