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

[Lu Baolu]

Hi,

On 11/11/19 11:21 AM, Deepa Dinamani wrote:
> 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.

Okay, thanks for the explanation.

> -Deepa

Best regards,
baolu