linux-kernel - RE: [PATCH v2] iommu/vt-d: Flush cache for PASID table before using it

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Message-ID: <BL1PR11MB52717592825AF5F237B71C9B8C87A@BL1PR11MB5271.namprd11.prod.outlook.com>
Date: Tue, 6 Jan 2026 07:51:54 +0000
From: "Tian, Kevin" <kevin.tian@...el.com>
To: Dmytro Maluka <dmaluka@...omium.org>, David Woodhouse
	<dwmw2@...radead.org>, Lu Baolu <baolu.lu@...ux.intel.com>,
	"iommu@...ts.linux.dev" <iommu@...ts.linux.dev>
CC: Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>, "Robin
 Murphy" <robin.murphy@....com>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>, "Vineeth Pillai (Google)"
	<vineeth@...byteword.org>, Aashish Sharma <aashish@...hishsharma.net>,
	Grzegorz Jaszczyk <jaszczyk@...omium.org>, "Dong, Chuanxiao"
	<chuanxiao.dong@...el.com>
Subject: RE: [PATCH v2] iommu/vt-d: Flush cache for PASID table before using
 it

> From: Dmytro Maluka <dmaluka@...omium.org>
> Sent: Sunday, December 21, 2025 8:35 PM
> 
> When writing the address of a freshly allocated zero-initialized PASID
> table to a PASID directory entry, do that after the CPU cache flush for
> this PASID table, not before it, to avoid the time window when this
> PASID table may be already used by non-coherent IOMMU hardware while
> its contents in RAM is still some random old data, not zero-initialized.
> 
> v1 -> v2:
> Add Fixes: tag.
> 
> Fixes: 194b3348bdbb ("iommu/vt-d: Fix PASID directory pointer coherency")
> Signed-off-by: Dmytro Maluka <dmaluka@...omium.org>

Reviewed-by: Kevin Tian <kevin.tian@...el.com>