On Fri, 2019-11-08 at 08:47 +0000, Zeng, Jason wrote: > > -----Original Message----- > > From: David Woodhouse <dw...@infradead.org> > > Sent: Friday, November 8, 2019 3:54 PM > > To: Deepa Dinamani <deepa.ker...@gmail.com>; j...@8bytes.org; linux- > > ker...@vger.kernel.org > > Cc: iommu@lists.linux-foundation.org; Zeng, Jason <jason.z...@intel.com>; > > Tian, Kevin <kevin.t...@intel.com> > > Subject: Re: [PATCH] intel-iommu: Turn off translations at shutdown > > > > 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. > > For VMM live update case, we should be able to detect and bypass > the shutdown that Deepa introduced here, so keep IOMMU still operating?
Is that a 'yes' to Deepa's "if someone wants to make it conditional, we can do that" ?
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