Re: [PATCH] iommu/amd: Fix iommu remap panic while amd_iommu is set to disable
From: Huang Rui
Date: Tue Mar 16 2021 - 09:37:09 EST
On Tue, Mar 16, 2021 at 09:16:34PM +0800, Joerg Roedel wrote:
> Hi Huang,
>
> On Thu, Mar 11, 2021 at 10:28:07PM +0800, Huang Rui wrote:
> > diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
> > index f0adbc48fd17..a08e885403b7 100644
> > --- a/drivers/iommu/amd/iommu.c
> > +++ b/drivers/iommu/amd/iommu.c
> > @@ -3862,7 +3862,7 @@ static int irq_remapping_select(struct irq_domain *d, struct irq_fwspec *fwspec,
> > else if (x86_fwspec_is_hpet(fwspec))
> > devid = get_hpet_devid(fwspec->param[0]);
> >
> > - if (devid < 0)
> > + if (devid < 0 || !amd_iommu_rlookup_table)
> > return 0;
>
> The problem is deeper than this fix suggests. I prepared other fixes for
> this particular problem. Please find them here:
>
Thanks for the comments. Could you please elaborate this?
Do you mean while amd_iommu=off, we won't prepare the IVRS, and even
needn't get all ACPI talbes. Because they are never be used and the next
state will always goes into IOMMU_CMDLINE_DISABLED, am I right?
Thanks,
Ray
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>
> Regards,
>
> Joerg