From: Jason Gunthorpe <jgg@nvidia.com>
To: Alexey Kardashevskiy <aik@amd.com>
Cc: dan.j.williams@intel.com, Robin Murphy <robin.murphy@arm.com>,
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Subject: Re: [PATCH kernel 4/9] dma/swiotlb: Stop forcing SWIOTLB for TDISP devices
Date: Wed, 4 Mar 2026 08:43:16 -0400 [thread overview]
Message-ID: <20260304124316.GL972761@nvidia.com> (raw)
In-Reply-To: <5d669086-a5c8-4e55-8108-a9fff41cf094@amd.com>
On Wed, Mar 04, 2026 at 05:45:31PM +1100, Alexey Kardashevskiy wrote:
> > I suspect AMD needs to use their vTOM feature to allow shared memory
> > to remain available to TDISP RUN with a high/low address split.
>
> I could probably do something about it bit I wonder what is the real
> live use case which requires leaking SME mask, have a live example
> which I could try recreating?
We need shared memory allocated through a DMABUF heap:
https://lore.kernel.org/all/20260223095136.225277-1-jiri@resnulli.us/
To work with all PCI devices in the system, TDISP or not.
Without this the ability for a TDISP device to ingest (encrypted) data
requires all kinds of memcpy..
So the DMA API should see the DMA_ATTR_CC_DECRYPTED and setup the
correct dma_dddr_t either by choosing the shared alias for the TDISP
device's vTOM, or setting the C bit in a vIOMMU S1.
Jason
next prev parent reply other threads:[~2026-03-04 12:43 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-25 5:37 [PATCH kernel 0/9] PCI/TSM: coco/sev-guest: Implement SEV-TIO PCIe TDISP (phase2) Alexey Kardashevskiy
2026-02-25 5:37 ` [PATCH kernel 1/9] pci/tsm: Add TDISP report blob and helpers to parse it Alexey Kardashevskiy
2026-02-25 6:16 ` dan.j.williams
2026-02-25 10:10 ` Arnd Bergmann
2026-02-26 0:09 ` Alexey Kardashevskiy
2026-02-26 2:34 ` dan.j.williams
2026-02-26 3:49 ` Alexey Kardashevskiy
2026-02-26 21:08 ` dan.j.williams
2026-02-25 5:37 ` [PATCH kernel 2/9] pci/tsm: Add tsm_tdi_status Alexey Kardashevskiy
2026-02-25 6:33 ` dan.j.williams
2026-02-25 23:42 ` Alexey Kardashevskiy
2026-03-02 6:58 ` Aneesh Kumar K.V
2026-02-25 5:37 ` [PATCH kernel 3/9] coco/sev-guest: Allow multiple source files in the driver Alexey Kardashevskiy
2026-02-25 5:37 ` [PATCH kernel 4/9] dma/swiotlb: Stop forcing SWIOTLB for TDISP devices Alexey Kardashevskiy
2026-02-25 16:30 ` dan.j.williams
2026-02-25 18:00 ` Robin Murphy
2026-02-25 20:57 ` dan.j.williams
2026-02-28 0:28 ` Jason Gunthorpe
2026-03-02 23:53 ` dan.j.williams
2026-03-03 0:19 ` Jason Gunthorpe
2026-03-03 0:29 ` dan.j.williams
2026-03-03 12:43 ` Jason Gunthorpe
2026-03-04 6:45 ` Alexey Kardashevskiy
2026-03-04 12:43 ` Jason Gunthorpe [this message]
2026-03-25 10:42 ` Alexey Kardashevskiy
2026-04-03 12:40 ` Alexey Kardashevskiy
2026-04-15 6:32 ` Alexey Kardashevskiy
2026-04-20 23:50 ` Jason Gunthorpe
2026-04-30 3:25 ` Alexey Kardashevskiy
2026-02-25 16:48 ` Robin Murphy
2026-02-26 0:09 ` Alexey Kardashevskiy
2026-03-02 7:54 ` Aneesh Kumar K.V
2026-02-25 5:37 ` [PATCH kernel 5/9] x86/mm: Stop forcing decrypted page state " Alexey Kardashevskiy
2026-02-25 16:51 ` dan.j.williams
2026-02-25 5:37 ` [PATCH kernel 6/9] x86/dma-direct: Stop changing encrypted " Alexey Kardashevskiy
2026-02-25 17:08 ` Robin Murphy
2026-02-25 21:35 ` dan.j.williams
2026-02-26 6:22 ` Alexey Kardashevskiy
2026-02-28 0:06 ` Jason Gunthorpe
2026-03-02 0:01 ` Alexey Kardashevskiy
2026-03-02 0:35 ` Jason Gunthorpe
2026-03-02 5:26 ` Alexey Kardashevskiy
2026-03-02 13:35 ` Jason Gunthorpe
2026-03-03 8:19 ` Alexey Kardashevskiy
2026-03-03 12:15 ` Jason Gunthorpe
2026-02-25 5:37 ` [PATCH kernel 7/9] coco/sev-guest: Implement the guest support for SEV TIO (phase2) Alexey Kardashevskiy
2026-02-25 6:00 ` Borislav Petkov
2026-02-26 3:39 ` Alexey Kardashevskiy
2026-02-26 19:52 ` Borislav Petkov
2026-02-25 5:37 ` [PATCH kernel 8/9] RFC: PCI: Avoid needless touching of Command register Alexey Kardashevskiy
2026-02-26 0:24 ` Bjorn Helgaas
2026-02-26 5:58 ` Alexey Kardashevskiy
2026-02-26 0:34 ` dan.j.williams
2026-02-25 5:37 ` [PATCH kernel 9/9] pci: Allow encrypted MMIO mapping via sysfs Alexey Kardashevskiy
2026-03-02 8:20 ` Aneesh Kumar K.V
2026-03-02 8:59 ` Alexey Kardashevskiy
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