[AMD Public Use] + Felix, Christian
> -----Original Message----- > From: Joerg Roedel <j...@8bytes.org> > Sent: Monday, August 24, 2020 6:54 AM > To: io...@lists.linux-foundation.org > Cc: Joerg Roedel <j...@8bytes.org>; jroe...@suse.de; Lendacky, Thomas > <thomas.lenda...@amd.com>; Suthikulpanit, Suravee > <suravee.suthikulpa...@amd.com>; Deucher, Alexander > <alexander.deuc...@amd.com>; linux-kernel@vger.kernel.org > Subject: [PATCH 1/2] iommu/amd: Do not force direct mapping when SME is > active > > From: Joerg Roedel <jroe...@suse.de> > > Do not force devices supporting IOMMUv2 to be direct mapped when > memory encryption is active. This might cause them to be unusable because > their DMA mask does not include the encryption bit. > > Signed-off-by: Joerg Roedel <jroe...@suse.de> > --- > drivers/iommu/amd/iommu.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c > index ba9f3dbc5b94..77e4268e41cf 100644 > --- a/drivers/iommu/amd/iommu.c > +++ b/drivers/iommu/amd/iommu.c > @@ -2659,7 +2659,12 @@ static int amd_iommu_def_domain_type(struct > device *dev) > if (!dev_data) > return 0; > > - if (dev_data->iommu_v2) > + /* > + * Do not identity map IOMMUv2 capable devices when memory > encryption is > + * active, because some of those devices (AMD GPUs) don't have the > + * encryption bit in their DMA-mask and require remapping. > + */ I think on the integrated GPUs in APUs I'd prefer to have the identity mapping over SME, but I guess this is fine because you have to explicitly enable SME and if you do that you know what you are getting into. Alex > + if (!mem_encrypt_active() && dev_data->iommu_v2) > return IOMMU_DOMAIN_IDENTITY; > > return 0; > -- > 2.28.0
