Re: [Xen-devel] [PATCH 2/2] iommu/amd: Workaround for ERBT1312

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 18.04.13 at 20:41, <suravee.suthikulpanit@xxxxxxx> wrote:

What is ERBT1312? Please reference at least the title of the document
containing this in the description, so that in few months/years time
one can still reconstruct what this refers to.

> --- a/xen/drivers/passthrough/amd/iommu_init.c
> +++ b/xen/drivers/passthrough/amd/iommu_init.c
> @@ -615,16 +615,23 @@ static void iommu_check_event_log(struct amd_iommu 
> *iommu)
>                     sizeof(event_entry_t), parse_event_log_entry);
>  
>      spin_lock_irqsave(&iommu->lock, flags);
> -    
> -    /*check event overflow */
> +
>      entry = readl(iommu->mmio_base + IOMMU_STATUS_MMIO_OFFSET);
>  
> -    if ( iommu_get_bit(entry, IOMMU_STATUS_EVENT_OVERFLOW_SHIFT) )
> -        iommu_reset_log(iommu, &iommu->event_log, 
> set_iommu_event_log_control);
> +    while (entry & IOMMU_STATUS_EVENT_LOG_INT_MASK) {
> +
> +     /*check event overflow */
> +        if ( iommu_get_bit(entry, IOMMU_STATUS_EVENT_OVERFLOW_SHIFT) )
> +            iommu_reset_log(iommu, &iommu->event_log,
> +                            set_iommu_event_log_control);
>  
> -    /* reset interrupt status bit */
> -    writel(IOMMU_STATUS_EVENT_LOG_INT_MASK, 
> -        iommu->mmio_base + IOMMU_STATUS_MMIO_OFFSET);
> +        /* reset interrupt status bit */
> +        writel(IOMMU_STATUS_EVENT_LOG_INT_MASK,
> +            iommu->mmio_base + IOMMU_STATUS_MMIO_OFFSET);
> +
> +        /* This is a hardware bug workaround (ERBT1312) */
> +        entry = readl(iommu->mmio_base + IOMMU_STATUS_MMIO_OFFSET);
> +    }
>  
>      spin_unlock_irqrestore(&iommu->lock, flags);
>  }
> @@ -681,18 +688,24 @@ static void iommu_check_ppr_log(struct amd_iommu *iommu)
>  
>      iommu_read_log(iommu, &iommu->ppr_log,
>                     sizeof(ppr_entry_t), parse_ppr_log_entry);
> -    
> +
>      spin_lock_irqsave(&iommu->lock, flags);
>  
> -    /*check event overflow */
>      entry = readl(iommu->mmio_base + IOMMU_STATUS_MMIO_OFFSET);
>  
> -    if ( iommu_get_bit(entry, IOMMU_STATUS_PPR_LOG_OVERFLOW_SHIFT) )
> -        iommu_reset_log(iommu, &iommu->ppr_log, set_iommu_ppr_log_control);
> +    while (entry & IOMMU_STATUS_PPR_LOG_INT_MASK) {
> +
> +        /*check event overflow */
> +        if ( iommu_get_bit(entry, IOMMU_STATUS_PPR_LOG_OVERFLOW_SHIFT) )
> +            iommu_reset_log(iommu, &iommu->ppr_log, 
> set_iommu_ppr_log_control);
>  
> -    /* reset interrupt status bit */
> -    writel(IOMMU_STATUS_PPR_LOG_INT_MASK, 
> -        iommu->mmio_base + IOMMU_STATUS_MMIO_OFFSET);
> +        /* reset interrupt status bit */
> +        writel(IOMMU_STATUS_PPR_LOG_INT_MASK,
> +            iommu->mmio_base + IOMMU_STATUS_MMIO_OFFSET);
> +
> +     /* This is a hardware bug workaround (ERBT1312) */
> +        entry = readl(iommu->mmio_base + IOMMU_STATUS_MMIO_OFFSET);
> +    }
>  
>      spin_unlock_irqrestore(&iommu->lock, flags);
>  }

This needs cleaning up from a coding style perspective: No hard
tabs, braces on separate lines, spaces inside the outermost
parentheses following keywords, a space following the opening /*
of comments, proper indentation of multi-line function arguments.

Jan


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