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From: David Woodhouse <dwmw2@infradead.org>
To: Deepa Dinamani <deepa.kernel@gmail.com>,
	joro@8bytes.org,  linux-kernel@vger.kernel.org
Cc: iommu@lists.linux-foundation.org, "Tian,
	Kevin" <kevin.tian@intel.com>,
	Jason.Zeng@intel.com
Subject: Re: [PATCH] intel-iommu: Turn off translations at shutdown
Date: Fri, 08 Nov 2019 07:54:17 +0000
Message-ID: <1672a5861c82c2e3c0c54b5311fd413a8eee5e64.camel@infradead.org> (raw)
In-Reply-To: <20191107205914.10611-1-deepa.kernel@gmail.com>

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On Thu, 2019-11-07 at 12:59 -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, we can do that.

This is going to break things for the VMM live update scheme that Jason
presented at KVM Forum, isn't it?

In that case we rely on the IOMMU still operating during the
transition.


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Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-07 20:59 Deepa Dinamani
2019-11-07 21:27 ` Deepa Dinamani
2019-11-08  3:07   ` Lu Baolu
2019-11-08  3:06 ` Lu Baolu
2019-11-08 22:28   ` Deepa Dinamani
2019-11-09  0:35     ` Lu Baolu
2019-11-08  7:54 ` David Woodhouse [this message]
2019-11-08  8:47   ` Zeng, Jason
2019-11-08  8:57     ` David Woodhouse
2019-11-08  9:11       ` Zeng, Jason
2019-11-08 22:48         ` Deepa Dinamani
2019-11-10 18:24           ` Deepa Dinamani
2019-11-10 20:36             ` Deepa Dinamani
2019-11-11  2:35               ` Zeng, Jason
2019-11-11  0:39           ` Zeng, Jason

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