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Subject: Re: [PATCH v3 6/7] iommu/vt-d: Warn on out-of-range invalidation
 address
To:     Jacob Pan <jacob.jun.pan@linux.intel.com>,
        iommu@lists.linux-foundation.org,
        LKML <linux-kernel@vger.kernel.org>,
        Lu Baolu <baolu.lu@linux.intel.com>,
        Joerg Roedel <joro@8bytes.org>,
        David Woodhouse <dwmw2@infradead.org>
Cc:     Yi Liu <yi.l.liu@intel.com>, "Tian, Kevin" <kevin.tian@intel.com>,
        Raj Ashok <ashok.raj@intel.com>
References: <1593617636-79385-1-git-send-email-jacob.jun.pan@linux.intel.com>
 <1593617636-79385-7-git-send-email-jacob.jun.pan@linux.intel.com>
From:   Auger Eric <eric.auger@redhat.com>
Message-ID: <7c265689-a23c-021b-27e7-beb3cd667a5f@redhat.com>
Date:   Thu, 2 Jul 2020 10:47:39 +0200
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Hi,

On 7/1/20 5:33 PM, 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.
What I don't really get is the guest shouldn't do that. Don't we want to
be more strict in that case and return an error?

Thanks

Eric
> 
> 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 6a0c62c7395c..2e1b53ade784 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;
> +				pr_err_ratelimited("User address not aligned, 0x%llx, size order %llu\n",
> +					  inv_info->addr_info.addr, size);
>  			}
>  
>  			/*
>