Re: [PATCH v2] iommu/vt-d: Turn off translations at shutdown

[Deepa Dinamani]

On Sun, Nov 10, 2019 at 5:35 PM Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx> wrote:
>
> Hi,
>
> On 11/11/19 1:27 AM, 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.
>
> Do you mind shining more light on this statement? I can't get your point
> here. Currently iommu_shutdown() only happens for reboot, right?

In this part, I'm saying that I'm leaving intel_iommu_init() alone.
I'm not taking out disabling the iommu from intel_iommu_init(). This
will help when BIOS has enabled the IOMMU and for whatever reason, the
kernel is booting with IOMMU off.

-Deepa