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From: Lu Baolu <baolu.lu@linux.intel.com>
To: "Liu, Yi L" <yi.l.liu@intel.com>, Joerg Roedel <joro@8bytes.org>,
	David Woodhouse <dwmw2@infradead.org>,
	Alex Williamson <alex.williamson@redhat.com>
Cc: "Tian, Kevin" <kevin.tian@intel.com>,
	"Raj, Ashok" <ashok.raj@intel.com>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"Kumar, Sanjay K" <sanjay.k.kumar@intel.com>,
	"iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Sun, Yi Y" <yi.y.sun@intel.com>
Subject: Re: [PATCH v3 4/6] iommu/vt-d: Setup pasid entries for iova over first level
Date: Tue, 17 Dec 2019 10:03:41 +0800	[thread overview]
Message-ID: <b883602c-ecdf-11ea-c26c-4b221bf7634d@linux.intel.com> (raw)
In-Reply-To: <A2975661238FB949B60364EF0F2C25743A132C9A@SHSMSX104.ccr.corp.intel.com>

Hi Yi,

On 12/15/19 5:37 PM, Liu, Yi L wrote:
>> XD (bit 63) is only for the first level, and SNP (bit 11) is only for second level, right? I
>> think we need to always set XD bit for IOVA over FL case. thoughts?
> Oops, I made a mistake here. Please forget SNP bit, there is no way to control SNP
> with first level page table.:-)
> 
> Actually, it is execute (bit 1) of second level page table which I wanted to say.
> If software sets R/W/X permission to an IOVA, with IOVA over second level
> page table, it will set bit 1. However, if IOVA is over first level page table, it
> may need to clear XD bit. This is what I want to say here. If IOVA doesn’t allow
> execute permission, it's ok to always set XD bit for IOVA over FL case. But I
> would like to do it just as what we did for R/W permission. R/W permission
> relies on the permission configured by the page map caller. right?

Got your point.

Current driver always cleard X (bit 2) in the second level page table.
So we will always set XD bit (bit 63) in the first level page table.
If we decide to use the X permission, we need a separated patch, right?

Best regards,
baolu
_______________________________________________
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iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

WARNING: multiple messages have this Message-ID (diff)
From: Lu Baolu <baolu.lu@linux.intel.com>
To: "Liu, Yi L" <yi.l.liu@intel.com>, Joerg Roedel <joro@8bytes.org>,
	David Woodhouse <dwmw2@infradead.org>,
	Alex Williamson <alex.williamson@redhat.com>
Cc: baolu.lu@linux.intel.com, "Raj, Ashok" <ashok.raj@intel.com>,
	"Kumar, Sanjay K" <sanjay.k.kumar@intel.com>,
	"jacob.jun.pan@linux.intel.com" <jacob.jun.pan@linux.intel.com>,
	"Tian, Kevin" <kevin.tian@intel.com>,
	"Sun, Yi Y" <yi.y.sun@intel.com>, Peter Xu <peterx@redhat.com>,
	"iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 4/6] iommu/vt-d: Setup pasid entries for iova over first level
Date: Tue, 17 Dec 2019 10:03:41 +0800	[thread overview]
Message-ID: <b883602c-ecdf-11ea-c26c-4b221bf7634d@linux.intel.com> (raw)
In-Reply-To: <A2975661238FB949B60364EF0F2C25743A132C9A@SHSMSX104.ccr.corp.intel.com>

Hi Yi,

On 12/15/19 5:37 PM, Liu, Yi L wrote:
>> XD (bit 63) is only for the first level, and SNP (bit 11) is only for second level, right? I
>> think we need to always set XD bit for IOVA over FL case. thoughts?
> Oops, I made a mistake here. Please forget SNP bit, there is no way to control SNP
> with first level page table.:-)
> 
> Actually, it is execute (bit 1) of second level page table which I wanted to say.
> If software sets R/W/X permission to an IOVA, with IOVA over second level
> page table, it will set bit 1. However, if IOVA is over first level page table, it
> may need to clear XD bit. This is what I want to say here. If IOVA doesn’t allow
> execute permission, it's ok to always set XD bit for IOVA over FL case. But I
> would like to do it just as what we did for R/W permission. R/W permission
> relies on the permission configured by the page map caller. right?

Got your point.

Current driver always cleard X (bit 2) in the second level page table.
So we will always set XD bit (bit 63) in the first level page table.
If we decide to use the X permission, we need a separated patch, right?

Best regards,
baolu

  reply	other threads:[~2019-12-17  2:04 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-11  2:12 [PATCH v3 0/6] Use 1st-level for IOVA translation Lu Baolu
2019-12-11  2:12 ` Lu Baolu
2019-12-11  2:12 ` [PATCH v3 1/6] iommu/vt-d: Identify domains using first level page table Lu Baolu
2019-12-11  2:12   ` Lu Baolu
2019-12-11  2:12 ` [PATCH v3 2/6] iommu/vt-d: Add set domain DOMAIN_ATTR_NESTING attr Lu Baolu
2019-12-11  2:12   ` Lu Baolu
2019-12-11  2:12 ` [PATCH v3 3/6] iommu/vt-d: Add PASID_FLAG_FL5LP for first-level pasid setup Lu Baolu
2019-12-11  2:12   ` Lu Baolu
2019-12-11  2:12 ` [PATCH v3 4/6] iommu/vt-d: Setup pasid entries for iova over first level Lu Baolu
2019-12-11  2:12   ` Lu Baolu
2019-12-13  9:23   ` Liu, Yi L
2019-12-13  9:23     ` Liu, Yi L
2019-12-14  3:03     ` Lu Baolu
2019-12-14  3:03       ` Lu Baolu
2019-12-15  9:37       ` Liu, Yi L
2019-12-15  9:37         ` Liu, Yi L
2019-12-17  2:03         ` Lu Baolu [this message]
2019-12-17  2:03           ` Lu Baolu
2019-12-17  2:33           ` Liu, Yi L
2019-12-17  2:33             ` Liu, Yi L
2019-12-11  2:12 ` [PATCH v3 5/6] iommu/vt-d: Flush PASID-based iotlb " Lu Baolu
2019-12-11  2:12   ` Lu Baolu
2019-12-13 11:42   ` Liu, Yi L
2019-12-13 11:42     ` Liu, Yi L
2019-12-14  3:24     ` Lu Baolu
2019-12-14  3:24       ` Lu Baolu
2019-12-15  9:22       ` Liu, Yi L
2019-12-15  9:22         ` Liu, Yi L
2019-12-17  1:19         ` Lu Baolu
2019-12-17  1:19           ` Lu Baolu
2019-12-17  1:37           ` Lu Baolu
2019-12-17  1:37             ` Lu Baolu
2019-12-17  1:39             ` Lu Baolu
2019-12-17  1:39               ` Lu Baolu
2019-12-17  2:44               ` Liu, Yi L
2019-12-17  2:44                 ` Liu, Yi L
2019-12-17  2:26             ` Liu, Yi L
2019-12-17  2:26               ` Liu, Yi L
2019-12-17  2:36               ` Liu, Yi L
2019-12-17  2:36                 ` Liu, Yi L
2019-12-17  4:13                 ` Lu Baolu
2019-12-17  4:13                   ` Lu Baolu
2019-12-11  2:12 ` [PATCH v3 6/6] iommu/vt-d: Use " Lu Baolu
2019-12-11  2:12   ` Lu Baolu

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