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Message-ID: <8839763d-8a40-caad-4048-0d335fb3beb9@linux.intel.com>
Date:   Tue, 28 Mar 2023 12:55:16 +0800
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Cc:     baolu.lu@linux.intel.com, Robin Murphy <robin.murphy@arm.com>,
        Will Deacon <will@kernel.org>,
        David Woodhouse <dwmw2@infradead.org>,
        Raj Ashok <ashok.raj@intel.com>,
        "Tian, Kevin" <kevin.tian@intel.com>, Yi Liu <yi.l.liu@intel.com>,
        "Yu, Fenghua" <fenghua.yu@intel.com>,
        Dave Jiang <dave.jiang@intel.com>,
        Tony Luck <tony.luck@intel.com>,
        "Zanussi, Tom" <tom.zanussi@intel.com>
Subject: Re: [PATCH v2 1/8] iommu/vt-d: Use non-privileged mode for all PASIDs
Content-Language: en-US
To:     Jacob Pan <jacob.jun.pan@linux.intel.com>,
        LKML <linux-kernel@vger.kernel.org>, iommu@lists.linux.dev,
        Jason Gunthorpe <jgg@nvidia.com>,
        Joerg Roedel <joro@8bytes.org>, dmaengine@vger.kernel.org,
        vkoul@kernel.org
References: <20230327232138.1490712-1-jacob.jun.pan@linux.intel.com>
 <20230327232138.1490712-2-jacob.jun.pan@linux.intel.com>
From:   Baolu Lu <baolu.lu@linux.intel.com>
In-Reply-To: <20230327232138.1490712-2-jacob.jun.pan@linux.intel.com>
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On 3/28/23 7:21 AM, Jacob Pan wrote:
> Supervisor Request Enable (SRE) bit in a PASID entry is for permission
> checking on DMA requests. When SRE = 0, DMA with supervisor privilege
> will be blocked. However, for in-kernel DMA this is not necessary in that
> we are targeting kernel memory anyway. There's no need to differentiate
> user and kernel for in-kernel DMA.
> 
> Let's use non-privileged (user) permission for all PASIDs used in kernel,
> it will be consistent with DMA without PASID (RID_PASID) as well.
> 
> Signed-off-by: Jacob Pan<jacob.jun.pan@linux.intel.com>

Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>

Best regards,
baolu