RE: [PATCH 2/2] iommu/amd: Do not use IOMMUv2 functionality when SME is active

["Deucher, Alexander" <Alexander.Deucher@amd.com>]

[AMD Public Use]

+ Felix, Christian

> -----Original Message-----
> From: Joerg Roedel <joro@8bytes.org>
> Sent: Monday, August 24, 2020 6:54 AM
> To: iommu@lists.linux-foundation.org
> Cc: Joerg Roedel <joro@8bytes.org>; jroedel@suse.de; Lendacky, Thomas
> <Thomas.Lendacky@amd.com>; Suthikulpanit, Suravee
> <Suravee.Suthikulpanit@amd.com>; Deucher, Alexander
> <Alexander.Deucher@amd.com>; linux-kernel@vger.kernel.org
> Subject: [PATCH 2/2] iommu/amd: Do not use IOMMUv2 functionality when
> SME is active
> 
> From: Joerg Roedel <jroedel@suse.de>
> 
> When memory encryption is active the device is likely not in a direct mapped
> domain. Forbid using IOMMUv2 functionality for now until finer grained
> checks for this have been implemented.
> 
> Signed-off-by: Joerg Roedel <jroedel@suse.de>
> ---
>  drivers/iommu/amd/iommu_v2.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/iommu/amd/iommu_v2.c
> b/drivers/iommu/amd/iommu_v2.c index c259108ab6dd..0d175aed1d92
> 100644
> --- a/drivers/iommu/amd/iommu_v2.c
> +++ b/drivers/iommu/amd/iommu_v2.c
> @@ -737,6 +737,13 @@ int amd_iommu_init_device(struct pci_dev *pdev,
> int pasids)
> 
>  	might_sleep();
> 
> +	/*
> +	 * When memory encryption is active the device is likely not in a
> +	 * direct-mapped domain. Forbid using IOMMUv2 functionality for
> now.
> +	 */
> +	if (mem_encrypt_active())
> +		return -ENODEV;
> +
>  	if (!amd_iommu_v2_supported())
>  		return -ENODEV;
> 
> --
> 2.28.0
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