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Subject: Re: [PATCH v2 06/10] iommu/vt-d: Fix off-by-one in PASID allocation
To:     Jacob Pan <jacob.jun.pan@linux.intel.com>,
        iommu@lists.linux-foundation.org,
        LKML <linux-kernel@vger.kernel.org>,
        Joerg Roedel <joro@8bytes.org>,
        Lu Baolu <baolu.lu@linux.intel.com>,
        David Woodhouse <dwmw2@infradead.org>
Cc:     "Tian, Kevin" <kevin.tian@intel.com>,
        Raj Ashok <ashok.raj@intel.com>, Yi Liu <yi.l.liu@intel.com>
References: <1574106153-45867-1-git-send-email-jacob.jun.pan@linux.intel.com>
 <1574106153-45867-7-git-send-email-jacob.jun.pan@linux.intel.com>
From:   Auger Eric <eric.auger@redhat.com>
Message-ID: <9226a541-3794-33f2-d4a8-420fff516a5d@redhat.com>
Date:   Mon, 18 Nov 2019 22:00:37 +0100
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Hi Jacob,

On 11/18/19 8:42 PM, Jacob Pan wrote:
> PASID allocator uses IDR which is exclusive for the end of the
> allocation range. There is no need to decrement pasid_max.
>=20
> Fixes: af39507305fb ("iommu/vt-d: Apply global PASID in SVA")
> Reported-by: Eric Auger <eric.auger@redhat.com>
> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
> Acked-by: Lu Baolu <baolu.lu@linux.intel.com>
> ---
>  drivers/iommu/intel-svm.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>=20
> diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
> index 74df10a39dfc..e90d0b914afe 100644
> --- a/drivers/iommu/intel-svm.c
> +++ b/drivers/iommu/intel-svm.c
> @@ -338,7 +338,7 @@ int intel_svm_bind_mm(struct device *dev, int *pasid,=
 int flags, struct svm_dev_
>  =09=09/* Do not use PASID 0 in caching mode (virtualised IOMMU) */
>  =09=09ret =3D intel_pasid_alloc_id(svm,
>  =09=09=09=09=09   !!cap_caching_mode(iommu->cap),
> -=09=09=09=09=09   pasid_max - 1, GFP_KERNEL);
> +=09=09=09=09=09   pasid_max, GFP_KERNEL);
>  =09=09if (ret < 0) {
>  =09=09=09kfree(svm);
>  =09=09=09kfree(sdev);
>=20
Reviewed-by: Eric Auger <eric.auger@redhat.com>

Thanks

Eric