Re: [PATCH 10/10] iommu/amd: Copy the old ir table

[Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>]

On Thu, Sep 24, 2015 at 02:37:36PM +0800, Baoquan He wrote:
> Signed-off-by: Baoquan He <bhe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> ---
>  drivers/iommu/amd_iommu.c | 25 +++++++++++++++++++------
>  1 file changed, 19 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
> index 1e86f4c..f4f3e63 100644
> --- a/drivers/iommu/amd_iommu.c
> +++ b/drivers/iommu/amd_iommu.c
> @@ -3683,12 +3683,25 @@ static struct irq_remap_table *get_irq_table(u16 devid, bool ioapic)
>  
>  	memset(table->table, 0, MAX_IRQS_PER_TABLE * sizeof(u32));
>  
> -	if (ioapic) {
> -		int i;
> -
> -		for (i = 0; i < 32; ++i)
> -			table->table[i] = IRTE_ALLOCATED;
> -	}
> +	if (translation_pre_enabled()) {
> +		u64 dte;
> +                u64 old_intr_virt;
> +                dte     = amd_iommu_dev_table[devid].data[2];
> +                dte &= DTE_IRQ_PHYS_ADDR_MASK;
> +                old_intr_virt = ioremap_cache(dte, MAX_IRQS_PER_TABLE * sizeof(u32));
> +                memcpy_fromio(table->table, old_intr_virt, MAX_IRQS_PER_TABLE * sizeof(u32));
> +                iounmap(old_intr_virt);
> +                iommu_flush_irt(iommu, devid);
> +        }
> +        else {
> +
> +                if (ioapic) {
> +                        int i;
> +
> +                        for (i = 0; i < 32; ++i)
> +                                table->table[i] = IRTE_ALLOCATED;
> +                }
> +        }

Is it necessary to copy the old ir tables? On AMD these tables are
per-device, so it is probably the best to handle them like the io
page-tables and just update the pointer to it in the device-table upon
interrupt initialization.


	Joerg