From: Joerg Roedel <joro@8bytes.org>
To: Baoquan He <bhe@redhat.com>
Cc: iommu@lists.linux-foundation.org, ahuang12@lenovo.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Revert "iommu/amd: Treat per-device exclusion ranges as r/w unity-mapped regions"
Date: Thu, 24 Sep 2020 11:08:57 +0200 [thread overview]
Message-ID: <20200924090857.GG27174@8bytes.org> (raw)
In-Reply-To: <20200923022655.750-1-bhe@redhat.com>
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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WARNING: multiple messages have this Message-ID (diff)
From: Joerg Roedel <joro@8bytes.org>
To: Baoquan He <bhe@redhat.com>
Cc: ahuang12@lenovo.com, iommu@lists.linux-foundation.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Revert "iommu/amd: Treat per-device exclusion ranges as r/w unity-mapped regions"
Date: Thu, 24 Sep 2020 11:08:57 +0200 [thread overview]
Message-ID: <20200924090857.GG27174@8bytes.org> (raw)
In-Reply-To: <20200923022655.750-1-bhe@redhat.com>
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
next prev parent reply other threads:[~2020-09-24 9:09 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-23 2:26 [PATCH] Revert "iommu/amd: Treat per-device exclusion ranges as r/w unity-mapped regions" Baoquan He
2020-09-23 2:26 ` Baoquan He
2020-09-23 2:32 ` Baoquan He
2020-09-23 2:32 ` Baoquan He
2020-09-23 14:29 ` [External] " Adrian Huang12
2020-09-23 14:29 ` Adrian Huang12
2020-09-24 9:08 ` Joerg Roedel [this message]
2020-09-24 9:08 ` Joerg Roedel
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