Messages in this thread | | | Date | Thu, 26 Oct 2023 16:00:08 +0530 | Subject | Re: [PATCH 0/3] Introduce DMA APIs to allocate and free TEE shared memory | From | "NK, JESHWANTHKUMAR" <> |
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On 25-Oct-23 7:01 PM, Sumit Garg wrote: > Hi Jeshwank, > > On Wed, 25 Oct 2023 at 12:27, jeshwank <JESHWANTHKUMAR.NK@amd.com> wrote: >> From: Jeshwanth Kumar N K <JESHWANTHKUMAR.NK@amd.com> >> >> At present, the shared memory for TEE ring buffer, command buffer and >> data buffer is allocated using get_free_pages(). The driver shares the >> physical address of these buffers with PSP so that it can be mapped by >> the Trusted OS. >> >> In this patch series we have replaced get_free_pages() with >> dma_alloc_coherent() to allocate shared memory to cleanup the existing >> allocation method. > Thanks for putting this together but I can't find the reasoning behind > this change neither in this commit message and nor in the patch > descriptions. Care to explain why? > > -Sumit Hi Sumit,
We see that there is an advantage in using dma_alloc_coherent() over get_free_pages(). The dma-ops associated with PSP PCIe device can be overridden. This capability will be helpful when we enable virtualization support. We plan to post a virtualization related patch in future.
Regards,
Jeshwanth
> >> Rijo Thomas (3): >> crypto: ccp - Add function to allocate and free memory using DMA APIs >> crypto: ccp - Use psp_tee_alloc_buffer() and psp_tee_free_buffer() >> tee: amdtee: Use psp_tee_alloc_buffer() and psp_tee_free_buffer() >> >> drivers/crypto/ccp/psp-dev.c | 3 + >> drivers/crypto/ccp/tee-dev.c | 119 ++++++++++++++++++---------- >> drivers/crypto/ccp/tee-dev.h | 11 +-- >> drivers/tee/amdtee/amdtee_private.h | 18 ++--- >> drivers/tee/amdtee/call.c | 74 ++++++++--------- >> drivers/tee/amdtee/core.c | 72 ++++++++++------- >> drivers/tee/amdtee/shm_pool.c | 21 ++--- >> include/linux/psp-tee.h | 47 +++++++++++ >> 8 files changed, 221 insertions(+), 144 deletions(-) >> >> -- >> 2.25.1 >>
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