lkml.org 
[lkml]   [2020]   [Jun]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 6/7] iommu/vt-d: Warn on out-of-range invalidation address
From
Date
Hi Jacob,

On 7/1/20 1:34 AM, Jacob Pan wrote:
> On Thu, 25 Jun 2020 18:10:43 +0800
> Lu Baolu<baolu.lu@linux.intel.com> wrote:
>
>> 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@linux.intel.com>
>>> ---
>>> 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()?
>>
> I think pr_warn_ratelimited might still be too chatty. There is no
> functional issues, we just don't to silently ignore it. Perhaps just
> say:
> WARN_ONCE(1, "User provided address not page aligned, alignment forced")
> ?
>

WARN() is normally used for reporting a kernel bug. It dumps kernel
trace. And the users will report bug through bugzilla.kernel.org.

In this case, it's actually an unexpected user input, we shouldn't
treat it as a kernel bug and pr_err_ratelimited() is enough?

Best regards,
baolu

\
 
 \ /
  Last update: 2020-07-01 03:51    [W:0.075 / U:0.016 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site