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Wed, 23 Sep 2026 08:21:25 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1x9Omi-0000000DrJM-1RIj; Wed, 23 Sep 2026 12:21:24 -0300 Date: Wed, 23 Sep 2026 12:21:24 -0300 From: Jason Gunthorpe To: "Aneesh Kumar K.V" Cc: Catalin Marinas , linux-coco@lists.linux.dev, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, iommu@lists.linux.dev, Andrew Morton , christian.koenig@amd.com, Joerg Roedel , Marc Zyngier , Marek Szyprowski , Robin Murphy , Steven Price , Sumit Semwal , Suzuki K Poulose , Thomas Gleixner , Will Deacon , dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-media@vger.kernel.org, linux-mm@kvack.org Subject: Re: [RFC PATCH v7 02/13] mm: Add an allocator for CoCo shared memory Message-ID: <20260923152124.GG1540250@ziepe.ca> References: <20260921144847.501151-1-aneesh.kumar@kernel.org> <20260921144847.501151-3-aneesh.kumar@kernel.org> <20260923130611.GF1540250@ziepe.ca> Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Wed, Sep 23, 2026 at 08:28:57PM +0530, Aneesh Kumar K.V wrote: > I'm also considering requiring the address passed to cc_make_shared() to > be in the linear map. This is currently required by both TDX and CCA, > while AMD SNP appears to support vmalloc addresses. The only user of > that vmalloc support is Hyper-V VMBus GPADL setup > (vmbus_establish_gpadl()). How should the generic CoCo shared-memory > allocator handle this? vmbus_establish_gpadl() is the the same wrong abstraction as the arch code. Get rid of it and use vmbus_establish_gpadl_caller_decrypted(): pdata->recv_buf = vzalloc(RECV_BUFFER_SIZE); if (!pdata->recv_buf) { ret = -ENOMEM; goto fail_free_ring; } ret = vmbus_establish_gpadl(channel, pdata->recv_buf, RECV_BUFFER_SIZE, &pdata->recv_gpadl); So you made an allocator that returns folios, now you just need to use that allocator to implement a kvzalloc wrapper. ARM can call vmap on decrypted memory with pgprot_decrypted(), right? Or maybe this can use vmbus_alloc_buffer(), it already does it. Jason