From: "Margolin, Michael" <mrgolin@amazon.com>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Tao Liu <ltao@redhat.com>, Gal Pressman <gal.pressman@linux.dev>,
<sleybo@amazon.com>, <leon@kernel.org>,
<kexec@lists.infradead.org>, <linux-kernel@vger.kernel.org>,
<linux-rdma@vger.kernel.org>
Subject: Re: Implementing .shutdown method for efa module
Date: Mon, 1 Apr 2024 16:23:32 +0300 [thread overview]
Message-ID: <0e7dddff-d7f3-4617-83e6-f255449a282b@amazon.com> (raw)
In-Reply-To: <20240326153223.GF8419@ziepe.ca>
Jason
Thanks for your response, efa_remove() is performing reset to the device
which should stop all DMA from the device.
Except skipping cleanups that are unnecessary for shutdown flow are
there any other reasons to prefer a separate function for shutdown?
Michael
On 3/26/2024 5:32 PM, Jason Gunthorpe wrote:
> CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you can confirm the sender and know the content is safe.
>
>
>
> On Tue, Mar 26, 2024 at 02:34:45PM +0200, Margolin, Michael wrote:
>> Hi Tao,
>>
>> Thanks for bringing this up.
>>
>> I've unsuccessfully tried to reproduce this kernel panic using production
>> Red Hat 9.3 AMI (5.14.0-362.18.1.el9_3.aarch64).
>>
>> Are there any related changes in the kernel you are testing?
>>
>> Anyways we do need to handle shutdown properly, please let know if calling
>> to efa_remove solves your issue.
> efa_remove should not be used for shutdown..
>
> If you have an iommu in your system (smmuv3 for this ARM64 case) then
> drivers must implement a shutdown handler or you will risk data
> corruption on ARM64 sytems during crash.
>
> The shutdown handler must stop all DMA from the device.
>
> If you don't have an iommu then the shutdown handler shouldn't be
> critical.
>
> Jason
next prev parent reply other threads:[~2024-04-01 13:24 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-25 2:10 Implementing .shutdown method for efa module Tao Liu
2024-03-25 8:06 ` Gal Pressman
2024-03-26 1:38 ` Tao Liu
2024-03-26 12:34 ` Margolin, Michael
2024-03-26 15:32 ` Jason Gunthorpe
2024-04-01 13:23 ` Margolin, Michael [this message]
2024-04-03 15:44 ` Jason Gunthorpe
2024-04-04 6:54 ` Margolin, Michael
2024-04-25 3:27 ` Tao Liu
2024-03-29 11:58 ` Tao Liu
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