Messages in this thread | | | Subject | Re: [PATCH 6/7] iommu/vt-d: Warn on out-of-range invalidation address | From | Lu Baolu <> | Date | Wed, 1 Jul 2020 09:45:40 +0800 |
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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
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