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From: Joerg Roedel <joro@8bytes.org>
To: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: linux-kernel@vger.kernel.org, baolu.lu@linux.intel.com,
	dwmw2@infradead.org, iommu@lists.linux-foundation.org
Subject: Re: [PATCH v2] iommu/vt-d: Turn off translations at shutdown
Date: Mon, 11 Nov 2019 16:08:15 +0100	[thread overview]
Message-ID: <20191111150815.GG18333@8bytes.org> (raw)
In-Reply-To: <20191110172744.12541-1-deepa.kernel@gmail.com>

On Sun, Nov 10, 2019 at 09:27:44AM -0800, Deepa Dinamani wrote:
> The intel-iommu driver assumes that the iommu state is
> cleaned up at the start of the new kernel.
> But, when we try to kexec boot something other than the
> Linux kernel, the cleanup cannot be relied upon.
> Hence, cleanup before we go down for reboot.
> 
> Keeping the cleanup at initialization also, in case BIOS
> leaves the IOMMU enabled.
> 
> I considered turning off iommu only during kexec reboot, but a clean
> shutdown seems always a good idea. But if someone wants to make it
> conditional, such as VMM live update, we can do that.  There doesn't
> seem to be such a condition at this time.
> 
> Tested that before, the info message
> 'DMAR: Translation was enabled for <iommu> but we are not in kdump mode'
> would be reported for each iommu. The message will not appear when the
> DMA-remapping is not enabled on entry to the kernel.
> 
> Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
> ---
> Changes since v1:
> * move shutdown registration to iommu detection
> 
>  drivers/iommu/dmar.c        |  5 ++++-
>  drivers/iommu/intel-iommu.c | 20 ++++++++++++++++++++
>  include/linux/dmar.h        |  2 ++
>  3 files changed, 26 insertions(+), 1 deletion(-)

Applied, thanks.

      parent reply	other threads:[~2019-11-11 15:08 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-10 17:27 [PATCH v2] iommu/vt-d: Turn off translations at shutdown Deepa Dinamani
2019-11-11  1:32 ` Lu Baolu
2019-11-11  3:21   ` Deepa Dinamani
2019-11-11  4:58     ` Lu Baolu
2019-11-11  5:00 ` Lu Baolu
2019-11-11 15:08 ` Joerg Roedel [this message]

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