From: Baolu Lu <baolu.lu@linux.intel.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: Joerg Roedel <joro@8bytes.org>,
Alex Williamson <alex.williamson@redhat.com>,
Kevin Tian <kevin.tian@intel.com>,
Jacob jun Pan <jacob.jun.pan@intel.com>,
Liu Yi L <yi.l.liu@intel.com>,
iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/5] iommu/vt-d: Set SNP bit only in second-level page table entries
Date: Wed, 4 May 2022 15:25:50 +0800 [thread overview]
Message-ID: <74172660-e9e9-6589-7755-50bcd8b0aca6@linux.intel.com> (raw)
In-Reply-To: <20220502130546.GI8364@nvidia.com>
Hi Jason,
On 2022/5/2 21:05, Jason Gunthorpe wrote:
> On Sun, May 01, 2022 at 07:24:31PM +0800, Lu Baolu wrote:
>> The SNP bit is only valid for second-level PTEs. Setting this bit in the
>> first-level PTEs has no functional impact because the Intel IOMMU always
>> ignores the same bit in first-level PTEs. Anyway, let's check the page
>> table type before setting SNP bit in PTEs to make the code more readable.
> Shouldn't this be tested before setting force_snooping and not during
> every map?
The check is in the following patch. This just makes sure that SNP is
only set in second-level page table entries.
Best regards,
baolu
next prev parent reply other threads:[~2022-05-04 7:26 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-01 11:24 [PATCH 0/5] iommu/vt-d: Force snooping improvement Lu Baolu
2022-05-01 11:24 ` [PATCH 1/5] iommu/vt-d: Block force-snoop domain attaching if no SC support Lu Baolu
2022-05-02 13:04 ` Jason Gunthorpe
2022-05-01 11:24 ` [PATCH 2/5] iommu/vt-d: Set SNP bit only in second-level page table entries Lu Baolu
2022-05-02 13:05 ` Jason Gunthorpe
2022-05-04 7:25 ` Baolu Lu [this message]
2022-05-04 13:31 ` Jason Gunthorpe
2022-05-04 14:37 ` Baolu Lu
2022-05-01 11:24 ` [PATCH 3/5] iommu/vt-d: Check domain force_snooping against attached devices Lu Baolu
2022-05-02 13:17 ` Jason Gunthorpe
2022-05-04 7:58 ` Baolu Lu
2022-05-02 21:31 ` Jacob Pan
2022-05-04 8:06 ` Baolu Lu
2022-05-01 11:24 ` [PATCH 4/5] iommu/vt-d: Remove domain_update_iommu_snooping() Lu Baolu
2022-05-02 13:19 ` Jason Gunthorpe
2022-05-02 21:36 ` Jacob Pan
2022-05-04 8:47 ` Baolu Lu
2022-05-01 11:24 ` [PATCH 5/5] iommu/vt-d: Remove hard coding PGSNP bit in PASID entries Lu Baolu
2022-05-02 13:19 ` Jason Gunthorpe
2022-05-04 8:49 ` Baolu Lu
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