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From: Nadav Amit <nadav.amit@gmail.com>
To: "Longpeng (Mike,
	Cloud Infrastructure Service Product Dept.)" 
	<longpeng2@huawei.com>
Cc: Lu Baolu <baolu.lu@linux.intel.com>,
	Alex Williamson <alex.williamson@redhat.com>,
	"dwmw2@infradead.org" <dwmw2@infradead.org>,
	"joro@8bytes.org" <joro@8bytes.org>,
	"will@kernel.org" <will@kernel.org>,
	"iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>,
	LKML <linux-kernel@vger.kernel.org>,
	"Gonglei (Arei)" <arei.gonglei@huawei.com>,
	chenjiashang <chenjiashang@huawei.com>,
	"Subo (Subo,
	Cloud Infrastructure Service Product Dept.)"  <subo7@huawei.com>
Subject: Re: A problem of Intel IOMMU hardware ?
Date: Thu, 18 Mar 2021 00:48:37 -0700	[thread overview]
Message-ID: <F609AED4-2238-43E0-8095-1659F945E277@gmail.com> (raw)
In-Reply-To: <a0ca6dd974be42878a8f51b0a7bbe00f@huawei.com>

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> On Mar 17, 2021, at 9:46 PM, Longpeng (Mike, Cloud Infrastructure Service Product Dept.) <longpeng2@huawei.com> wrote:
> 

[Snip]

> 
> NOTE, the magical thing happen...(*Operation-4*) we write the PTE
> of Operation-1 from 0 to 0x3 which means can Read/Write, and then
> we trigger DMA read again, it success and return the data of HPA 0 !!
> 
> Why we modify the older page table would make sense ? As we
> have discussed previously, the cache flush part of the driver is correct,
> it call flush_iotlb after (b) and no need to flush after (c). But the result
> of the experiment shows the older page table or older caches is effective
> actually.
> 
> Any ideas ?

Interesting. Sounds as if there is some page-walk cache that was not
invalidated properly.


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  reply	other threads:[~2021-03-18  7:49 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-17  3:16 A problem of Intel IOMMU hardware ? Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2021-03-17  5:16 ` Lu Baolu
2021-03-17  9:40   ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2021-03-17 15:18   ` Alex Williamson
2021-03-18  2:58     ` Lu Baolu
2021-03-18  4:46       ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2021-03-18  7:48         ` Nadav Amit [this message]
2021-03-17  5:46 ` Nadav Amit
2021-03-17  9:35   ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2021-03-17 18:12     ` Nadav Amit
2021-03-18  3:03       ` Lu Baolu
2021-03-18  8:20       ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2021-03-18  8:27         ` Tian, Kevin
2021-03-18  8:38           ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2021-03-18  8:43             ` Tian, Kevin
2021-03-18  8:54               ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2021-03-18  8:56             ` Tian, Kevin
2021-03-18  9:25               ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2021-03-18 16:46                 ` Nadav Amit
2021-03-21 23:51                   ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2021-03-22  0:27                   ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2021-03-27  2:31                   ` Lu Baolu
2021-03-27  4:36                     ` Nadav Amit
2021-03-27  5:27                       ` Lu Baolu
2021-03-19  0:15               ` Lu Baolu

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