linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Christian Borntraeger <borntraeger@de.ibm.com>
To: Halil Pasic <pasic@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>,
	iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
	Guenter Roeck <linux@roeck-us.net>,
	Claire Chang <tientzu@chromium.org>,
	Christoph Hellwig <hch@lst.de>,
	Robin Murphy <robin.murphy@arm.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	Nathan Chancellor <nathan@kernel.org>,
	linux-s390 <linux-s390@vger.kernel.org>,
	Heiko Carstens <heiko.carstens@de.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>
Subject: Re: [PATCH v2 0/4] Fix restricted DMA vs swiotlb_exit()
Date: Fri, 23 Jul 2021 07:51:24 +0200	[thread overview]
Message-ID: <62da6479-a000-0b1a-d251-c4e27616fbc2@de.ibm.com> (raw)
In-Reply-To: <20210723031252.655d6a83.pasic@linux.ibm.com>



On 23.07.21 03:12, Halil Pasic wrote:
> On Thu, 22 Jul 2021 21:22:58 +0200
> Christian Borntraeger <borntraeger@de.ibm.com> wrote:
> 
>> On 20.07.21 15:38, Will Deacon wrote:
>>> Hi again, folks,
>>>
>>> This is version two of the patch series I posted yesterday:
>>>
>>>     https://lore.kernel.org/r/20210719123054.6844-1-will@kernel.org
>>>
>>> The only changes since v1 are:
>>>
>>>     * Squash patches 2 and 3, amending the commit message accordingly
>>>     * Add Reviewed-by and Tested-by tags from Christoph and Claire (thanks!)
>>>
>>> I'd usually leave it a bit longer between postings, but since this fixes
>>> issues with patches in -next I thought I'd spin a new version immediately.
>>>
>>> Cheers,
>>
>> FWIW, I just bisected virtio-errors with secure execution mode
>> qemu-system-s390x: virtio-serial-bus: Unexpected port id 4205794771 for device virtio-serial0.0
>>
>> to
>> commit 903cd0f315fe426c6a64c54ed389de0becb663dc
>> Author: Claire Chang <tientzu@chromium.org>
>> Date:   Thu Jun 24 23:55:20 2021 +0800
>>
>>        swiotlb: Use is_swiotlb_force_bounce for swiotlb data bouncing
>>
>> Unfortunately this patch series does NOT fix this issue, so it seems that even more
>> things are broken.
>>
>> Any idea what else might be broken?
> 
> I've done some debugging, and I think I know what is going on. Since
> that commit we need to set force_swiotlb before the swiotlb itself is
> initialized. So the patch below should fix the problem.
> 
> --------------------8<-------------------------------------
> 
> From: Halil Pasic <pasic@linux.ibm.com>
> Date: Fri, 23 Jul 2021 02:57:06 +0200
> Subject: [PATCH 1/1] s390/pv: fix the forcing of the swiotlb
> 
> Since commit 903cd0f315fe ("swiotlb: Use is_swiotlb_force_bounce for
> swiotlb data bouncing") if code sets swiotlb_force it needs to do so
> before the swiotlb is initialised. Otherwise
> io_tlb_default_mem->force_bounce will not get set to true, and devices
> that use (the default) swiotlb will not bounce  despite switolb_force
> having the value of SWIOTLB_FORCE.
> 
> Let us restore swiotlb functionality for PV by fulfilling this new
> requirement.
> 
I would add:
Fixes: 903cd0f315fe ("swiotlb: Use is_swiotlb_force_bounce for swiotlb data bouncing")
as this patch breaks things
and
Fixes: 64e1f0c531d1 ("s390/mm: force swiotlb for protected virtualization")

to make the s390 init code more robust in case people start backporting things.

> Signed-off-by: Halil Pasic <pasic@linux.ibm.com>

I can confirm that this fixes the problem. This also makes sense codewise.

Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>

Konrad, Heiko, Vasily, any preference which tree this goes? I think s390
would be easiest, but that requires that the patches in the swiotlb tree have
fixed commit IDs.

> ---
>   arch/s390/mm/init.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
> index 8ac710de1ab1..07bbee9b7320 100644
> --- a/arch/s390/mm/init.c
> +++ b/arch/s390/mm/init.c
> @@ -186,9 +186,9 @@ static void pv_init(void)
>   		return;
>   
>   	/* make sure bounce buffers are shared */
> +	swiotlb_force = SWIOTLB_FORCE;
>   	swiotlb_init(1);
>   	swiotlb_update_mem_attributes();
> -	swiotlb_force = SWIOTLB_FORCE;
>   }
>   
>   void __init mem_init(void)
> 

  reply	other threads:[~2021-07-23  5:52 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-20 13:38 [PATCH v2 0/4] Fix restricted DMA vs swiotlb_exit() Will Deacon
2021-07-20 13:38 ` [PATCH v2 1/4] of: Return success from of_dma_set_restricted_buffer() when !OF_ADDRESS Will Deacon
2021-07-20 13:38 ` [PATCH v2 2/4] swiotlb: Convert io_default_tlb_mem to static allocation Will Deacon
2021-07-20 13:38 ` [PATCH v2 3/4] swiotlb: Emit diagnostic in swiotlb_exit() Will Deacon
2021-07-20 13:38 ` [PATCH v2 4/4] swiotlb: Free tbl memory " Will Deacon
2021-07-31 18:26   ` Guenter Roeck
2021-08-01  2:29     ` Konrad Rzeszutek Wilk
2021-08-01  4:26       ` Guenter Roeck
2021-07-22 19:22 ` [PATCH v2 0/4] Fix restricted DMA vs swiotlb_exit() Christian Borntraeger
2021-07-23  1:12   ` Halil Pasic
2021-07-23  5:51     ` Christian Borntraeger [this message]
2021-07-23  6:14     ` Christian Borntraeger
2021-07-23  8:47       ` Halil Pasic
2021-07-23  8:50         ` Christian Borntraeger
2021-07-23 14:01           ` Konrad Rzeszutek Wilk
2021-07-23 17:53             ` Christian Borntraeger
2021-07-23 22:18               ` Halil Pasic
2021-07-24  0:29 ` Konrad Rzeszutek Wilk

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=62da6479-a000-0b1a-d251-c4e27616fbc2@de.ibm.com \
    --to=borntraeger@de.ibm.com \
    --cc=gor@linux.ibm.com \
    --cc=hch@lst.de \
    --cc=heiko.carstens@de.ibm.com \
    --cc=iommu@lists.linux-foundation.org \
    --cc=konrad.wilk@oracle.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-s390@vger.kernel.org \
    --cc=linux@roeck-us.net \
    --cc=nathan@kernel.org \
    --cc=pasic@linux.ibm.com \
    --cc=robin.murphy@arm.com \
    --cc=tientzu@chromium.org \
    --cc=will@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).