Re: [PATCH -stable] amd_iommu: attach device fails on the last pcidevice

[Alex Williamson]

On Fri, 2012-10-12 at 10:29 -0600, Shuah Khan wrote:
> amd_iommu_attach_device() checks if device id is within the limits
> of amd_iommu_last_bdf and instead checking if devid > amd_iommu_last_bdf,
> it checks devid >= amd_iommu_last_bdf. As a result the last device attach
> fails because amd_iommu_attach_device() returns an -EINVAL.
> 
> This bug is in linux-2.6.32 and an equivalent fix in linux-2.6.33 and has been
> carried forward to later kernels and is in the upstream kernel. This equivalent
> fix includes restructuring and consolidating device checks into a routine
> check_device(). Instead of back-porting all of that work, spot-fixed the bug in
> amd_iommu_attach_device() for linux-2.6.32.
> 
> Signed-off-by: Shuah Khan <shuah.khan@xxxxxx>
> CC: <stable@xxxxxxxxxxxxxxx> v2.6.32
> ---
>  arch/x86/kernel/amd_iommu.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
> index 3a44b75..67de7d7 100644
> --- a/arch/x86/kernel/amd_iommu.c
> +++ b/arch/x86/kernel/amd_iommu.c
> @@ -2288,7 +2288,7 @@ static int amd_iommu_attach_device(struct iommu_domain *dom,
>  
>  	devid = calc_devid(pdev->bus->number, pdev->devfn);
>  
> -	if (devid >= amd_iommu_last_bdf ||
> +	if (devid > amd_iommu_last_bdf ||
>  			devid != amd_iommu_alias_table[devid])
>  		return -EINVAL;
>  

Looks correct to me, this case was clearly inconsistent with other users
of amd_iommu_last_bdf.

Reviewed-by: Alex Williamson <alex.williamson@xxxxxxxxxx>

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