From: Jason Gunthorpe <jgg@ziepe.ca>
To: Jie Ji <jijie.ji@linux.alibaba.com>
Cc: dwmw2@infradead.org, baolu.lu@linux.intel.com, joro@8bytes.org,
will@kernel.org, robin.murphy@arm.com, iommu@lists.linux.dev,
linux-kernel@vger.kernel.org, xianting.tian@linux.alibaba.com,
kaijieguo@linux.alibaba.com, daishengdong@yeah.net
Subject: Re: [PATCH] iommu/vt-d: Atomic breakdown of IOPT into finer granularity
Date: Tue, 15 Aug 2023 11:34:35 -0300 [thread overview]
Message-ID: <ZNuM+3R197oRfBer@ziepe.ca> (raw)
In-Reply-To: <20230814121016.32613-1-jijie.ji@linux.alibaba.com>
On Mon, Aug 14, 2023 at 08:10:16PM +0800, Jie Ji wrote:
> With the addition of IOMMU support for IO page fault, it's now possible
> to unpin the memory which DMA remapping. However, the lack of support
> for unmapping a subrange of the I/O page table (IOPT) in IOMMU can lead
> to some issues.
>
> For instance, a virtual machine can establish IOPT of 2M/1G for better
> performance, while the host system enable swap and attempts to swap out
> some 4K pages. Unfortunately, unmap subrange of the large-page mapping
> will make IOMMU page walk to error level, and finally cause kernel crash.
Nothing in-kernel does something like this.
Jason
prev parent reply other threads:[~2023-08-15 14:35 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-14 12:10 [PATCH] iommu/vt-d: Atomic breakdown of IOPT into finer granularity Jie Ji
2023-08-14 12:15 ` Xianting Tian
2023-08-15 2:05 ` Baolu Lu
2023-08-15 3:15 ` Tian, Kevin
[not found] ` <BN9PR11MB527619D76C1ACFA5B85E2DEB8C14A@BN9PR11MB5276.namprd11.prod.outlook.com>
2023-08-15 4:00 ` Tian, Kevin
[not found] ` <ae72631d-31a4-eba0-b2f3-de4cf6c7d067@linux.alibaba.com>
2023-08-15 11:31 ` Jason Gunthorpe
2023-08-15 14:34 ` Jason Gunthorpe [this message]
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