Messages in this thread | | | Date | Thu, 24 Sep 2020 11:08:57 +0200 | From | Joerg Roedel <> | Subject | Re: [PATCH] Revert "iommu/amd: Treat per-device exclusion ranges as r/w unity-mapped regions" |
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On Wed, Sep 23, 2020 at 10:26:55AM +0800, Baoquan He wrote: > A regression failure of kdump kernel boot was reported on a HPE system. > Bisect points at commit 387caf0b759ac43 ("iommu/amd: Treat per-device > exclusion ranges as r/w unity-mapped regions") as criminal. Reverting it > fix the failure. > > With the commit, kdump kernel will always print below error message, then > naturally AMD iommu can't function normally during kdump kernel bootup. > > ~~~~~~~~~ > AMD-Vi: [Firmware Bug]: IVRS invalid checksum > > Why commit 387caf0b759ac43 causing it haven't been made clear.
I think this should be debugged further, in future IOMMUs the exclusion range feature will not be available anymore (mmio-fields get re-used for SNP). So starting to use them again is not going to work.
Regards,
Joerg
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