From: Jonathan Cameron <jonathan.cameron@huawei.com>
To: "Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel.org>
Cc: <linux-coco@lists.linux.dev>, <kvmarm@lists.linux.dev>,
<linux-pci@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<dan.j.williams@intel.com>, <aik@amd.com>, <lukas@wunner.de>,
Samuel Ortiz <sameo@rivosinc.com>,
Xu Yilun <yilun.xu@linux.intel.com>,
Jason Gunthorpe <jgg@ziepe.ca>,
Suzuki K Poulose <Suzuki.Poulose@arm.com>,
Steven Price <steven.price@arm.com>,
Bjorn Helgaas <helgaas@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Marc Zyngier <maz@kernel.org>, Will Deacon <will@kernel.org>,
Oliver Upton <oliver.upton@linux.dev>
Subject: Re: [PATCH v2 10/11] coco: arm64: dma: Update force_dma_unencrypted for accepted devices
Date: Thu, 20 Nov 2025 17:58:07 +0000 [thread overview]
Message-ID: <20251120175807.00007c2e@huawei.com> (raw)
In-Reply-To: <20251117140007.122062-11-aneesh.kumar@kernel.org>
On Mon, 17 Nov 2025 19:30:06 +0530
"Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel.org> wrote:
> This change updates the DMA behavior for accepted devices by assuming
> they access only private memory. Currently, the DMA API does not provide
> a mechanism for allocating shared memory that can be accessed by both
> the secure realm and the non-secure host.
>
> Accepted devices are therefore expected to operate entirely within the
> private memory space. As of now, there is no API in the DMA layer that
> allows such devices to explicitly request shared memory allocations for
> coherent data exchange with the host.
Isn't this sentence a bit of a repeat of the one at the end of the
1st paragraph.
>
> If future use cases require accepted devices to interact with shared
> memory— for example, for host-device communication, we will need to
> extend the DMA interface to support such allocation semantics. This
> commit lays the groundwork for that by clearly defining the current
> assumption and isolating the enforcement to force_dma_unencrypted.
>
> Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
next prev parent reply other threads:[~2025-11-20 17:58 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-17 13:59 [PATCH v2 00/11] TSM: Implement ->lock()/->accept() callbacks for ARM CCA TDISP setup Aneesh Kumar K.V (Arm)
2025-11-17 13:59 ` [PATCH v2 01/11] coco: guest: arm64: Guest TSM callback and realm device lock support Aneesh Kumar K.V (Arm)
2025-11-19 15:22 ` Jonathan Cameron
2025-11-17 13:59 ` [PATCH v2 02/11] coco: guest: arm64: Add Realm Host Interface and guest DA helper Aneesh Kumar K.V (Arm)
2025-11-19 15:32 ` Jonathan Cameron
2025-11-17 13:59 ` [PATCH v2 03/11] coco: guest: arm64: Add support for guest initiated TDI bind/unbind Aneesh Kumar K.V (Arm)
2025-11-19 15:50 ` Jonathan Cameron
2025-11-17 14:00 ` [PATCH v2 04/11] coco: guest: arm64: Add support for updating interface reports from device Aneesh Kumar K.V (Arm)
2025-11-19 15:54 ` Jonathan Cameron
2025-11-17 14:00 ` [PATCH v2 05/11] coco: guest: arm64: Add support for updating measurements " Aneesh Kumar K.V (Arm)
2025-11-20 15:22 ` Jonathan Cameron
2025-11-17 14:00 ` [PATCH v2 06/11] coco: guest: arm64: Add support for reading cached objects from host Aneesh Kumar K.V (Arm)
2025-11-20 17:31 ` Jonathan Cameron
2025-11-17 14:00 ` [PATCH v2 07/11] coco: guest: arm64: Validate Realm MMIO mappings from TDISP report Aneesh Kumar K.V (Arm)
2025-11-20 17:43 ` Jonathan Cameron
2025-11-17 14:00 ` [PATCH v2 08/11] coco: guest: arm64: Add support for fetching and verifying device info Aneesh Kumar K.V (Arm)
2025-11-20 17:54 ` Jonathan Cameron
2025-11-17 14:00 ` [PATCH v2 09/11] coco: guest: arm64: Wire Realm TDISP RUN/STOP transitions into guest driver Aneesh Kumar K.V (Arm)
2025-11-20 17:55 ` Jonathan Cameron
2025-11-17 14:00 ` [PATCH v2 10/11] coco: arm64: dma: Update force_dma_unencrypted for accepted devices Aneesh Kumar K.V (Arm)
2025-11-20 17:58 ` Jonathan Cameron [this message]
2025-11-17 14:00 ` [PATCH v2 11/11] coco: guest: arm64: Enable vdev DMA after attestation Aneesh Kumar K.V (Arm)
2025-11-20 17:59 ` Jonathan Cameron
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