From: Jason Gunthorpe <jgg@ziepe.ca>
To: Vasant Hegde <vasant.hegde@amd.com>
Cc: Robin Murphy <robin.murphy@arm.com>,
iommu@lists.linux.dev, joro@8bytes.org,
suravee.suthikulpanit@amd.com, Lianbo Jiang <lijiang@redhat.com>
Subject: Re: [PATCH 1/2] iommu: Take group lock before attaching device in iommu_deferred_attach()
Date: Mon, 24 Jun 2024 12:25:34 -0300 [thread overview]
Message-ID: <20240624152534.GR791043@ziepe.ca> (raw)
In-Reply-To: <1bd088e9-8cb3-476a-b397-4257d3ec1b46@amd.com>
On Mon, Jun 24, 2024 at 07:50:46PM +0530, Vasant Hegde wrote:
> It may be good thing to add mutex here.. But if any of the caller of these
> deferred functions hold spin lock again we will hit the similar issue that I hit
> with AMD driver.
My point was that Intel doesn't support non-sleeping attach, it uses
GFP_KERNEL, that support seems to be a uniquely AMD thing of the major
drivers.
So, I don't see an issue with formalizing the lowest common
denominator in the core code - the context must be sleepable.
Presumably things work because the kdump kernels only run drivers that
reliably trigger first dma from sleepable contexts. Unless there is
something AMD only that relies on this special behavior??
Jason
next prev parent reply other threads:[~2024-06-24 15:25 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-28 16:39 [PATCH 1/2] iommu: Take group lock before attaching device in iommu_deferred_attach() Vasant Hegde
2024-05-28 16:39 ` [PATCH 2/2] iommu/amd: Fix Invalid wait context issue Vasant Hegde
2024-05-28 20:43 ` Chris Bainbridge
2024-05-29 6:35 ` Mikhail Gavrilov
2024-05-28 18:06 ` [PATCH 1/2] iommu: Take group lock before attaching device in iommu_deferred_attach() Robin Murphy
2024-05-29 7:24 ` Vasant Hegde
2024-06-10 17:44 ` Jason Gunthorpe
2024-06-24 14:20 ` Vasant Hegde
2024-06-24 15:25 ` Jason Gunthorpe [this message]
2024-06-24 16:02 ` Vasant Hegde
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