From: Joerg Roedel <joro@8bytes.org>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
Will Deacon <will@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
Vasant Hegde <vasant.hegde@amd.com>,
linux-doc@vger.kernel.org, iommu@lists.linux.dev,
linux-kernel@vger.kernel.org, Joerg Roedel <jroedel@suse.de>
Subject: Re: [PATCH] iommu/amd: Add parameter to limit V1 page-sizes to 4 KiB
Date: Wed, 4 Sep 2024 15:15:16 +0200 [thread overview]
Message-ID: <ZthdZElA6KEMtYxt@8bytes.org> (raw)
In-Reply-To: <20240904130329.GC3915968@nvidia.com>
On Wed, Sep 04, 2024 at 10:03:29AM -0300, Jason Gunthorpe wrote:
> Why is this a kernel command line? Surely it should be negotiated
> automaticaly with capability registers or ACPI like everone else does
> if there is something functionally wrong with the vIOMMU??
In the affected setups there is no vIOMMU. This is not about secure-IO,
the assigned devices will not be part of the trusted base.
> If we are doing this we also have a problem on mlx5 devices where
> there are too many page sizes in the v1 table and it blows up the ATS
> caching. It would be nice to widen this option to limit the page sizes
> to other combinations (4k/2M/1G or something).
Okay, I will update the patch to allow more settings.
Regards,
Joerg
prev parent reply other threads:[~2024-09-04 13:15 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-09-04 12:59 [PATCH] iommu/amd: Add parameter to limit V1 page-sizes to 4 KiB Joerg Roedel
2024-09-04 13:03 ` Jason Gunthorpe
2024-09-04 13:15 ` Joerg Roedel [this message]
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