Re: [PATCH 6/7] iommu/vt-d: Warn on out-of-range invalidation address

[Lu Baolu]

Hi,

On 2020/6/23 23:43, Jacob Pan wrote:
> For guest requested IOTLB invalidation, address and mask are provided as
> part of the invalidation data. VT-d HW silently ignores any address bits
> below the mask. SW shall also allow such case but give warning if
> address does not align with the mask. This patch relax the fault
> handling from error to warning and proceed with invalidation request
> with the given mask.
>
> Signed-off-by: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
> ---
>   drivers/iommu/intel/iommu.c | 7 +++----
>   1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index 5ea5732d5ec4..50fc62413a35 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -5439,13 +5439,12 @@ intel_iommu_sva_invalidate(struct iommu_domain *domain, struct device *dev,
>   
>   		switch (BIT(cache_type)) {
>   		case IOMMU_CACHE_INV_TYPE_IOTLB:
> +			/* HW will ignore LSB bits based on address mask */
>   			if (inv_info->granularity == IOMMU_INV_GRANU_ADDR &&
>   			    size &&
>   			    (inv_info->addr_info.addr & ((BIT(VTD_PAGE_SHIFT + size)) - 1))) {
> -				pr_err_ratelimited("Address out of range, 0x%llx, size order %llu\n",
> -						   inv_info->addr_info.addr, size);
> -				ret = -ERANGE;
> -				goto out_unlock;
> +				WARN_ONCE(1, "Address out of range, 0x%llx, size order %llu\n",
> +					  inv_info->addr_info.addr, size);

I don't think WARN_ONCE() is suitable here. It makes users think it's a
kernel bug. How about pr_warn_ratelimited()?

Best regards,
baolu

>   			}
>   
>   			/*