Hi Tom,
On 26-Oct-23 8:23 PM, Tom Lendacky wrote:
On 10/26/23 05:30, NK, JESHWANTHKUMAR wrote:
On 25-Oct-23 7:01 PM, Sumit Garg wrote:
Hi Jeshwank,
On Wed, 25 Oct 2023 at 12:27, jeshwank <JESHWANTHKUMAR.NK@xxxxxxx>
wrote:
From: Jeshwanth Kumar N K <JESHWANTHKUMAR.NK@xxxxxxx>
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.
To be specific, you are referring to Xen virtualization support,
correct? Because I don't see how this works in a Qemu/KVM environment
where you would get a GPA and not an SPA.
The patch is not specific to Xen. We have verified it in Qemu/KVM and
Xen PV mode. Support for Xen PVH mode will be added as a separate patch.
If that is the case, you should clearly specify that. Also, this looks
like it should be introduced with the virtualization support that you
submit in the future and not before.
I will update the commit message in the next version of the patch series
to include these details.
Thanks,
Tom
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
