Re: [PATCH] tee: amdtee: add support for use of cma region

On 8/19/2023 4:34 AM, Randy Dunlap wrote:

Hi--

On 8/18/23 07:42, Devaraj Rangasamy wrote:

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diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 722b6eca2e93..5e38423f3d53 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -363,6 +363,13 @@ selects a performance level in this range and appropriate to the current workload.

• amdtee_cma=nn [HW,TEE]

• 	Sets the memory size reserved for contiguous memory
  

• 	allocations, to be used by amdtee device driver.
  

• 	Value is in MB and can range from 4 to 128 (MBs)
  

	                                       128 (MBs).

Ack. In updated patch, we dont use new custom kernel command line parameter, and resorted to generic cma zone.

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• 	CMA will be active only when CMA is enabled, and amdtee is
  

That could use some improvement. How about:

	AMD-TEE CMA will be active only when CONFIG_CMA is enabled,
	and amdtee is

Ack, as above.

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• 	built as inbuilt driver, and not loaded as module.
  

• amijoy.map= [HW,JOY] Amiga joystick support Map of devices attached to JOY0DAT and JOY1DAT Format: <a>,<b>

diff --git a/drivers/tee/amdtee/Kconfig b/drivers/tee/amdtee/Kconfig index 191f9715fa9a..5843c739a7b8 100644 --- a/drivers/tee/amdtee/Kconfig +++ b/drivers/tee/amdtee/Kconfig @@ -6,3 +6,12 @@ config AMDTEE depends on CRYPTO_DEV_SP_PSP && CRYPTO_DEV_CCP_DD help This implements AMD's Trusted Execution Environment (TEE) driver.

+config AMDTEE_CMA_SIZE

• int "Size of Memory in MiB reserved in CMA for AMD-TEE"
• default "0"

Why won't this default value cause an allocation error message? Maybe I'm just not following the call paths correctly.

It looks to me like this causes a call to cma_declare_contiguous_nid() with @size = 0, and that function says:

if (!size) return -EINVAL;

Ack. It did resulted in error message. We have revoked new exclusive cma zone now.

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• depends on CMA && (AMDTEE=y)
• help

•  Specify the default amount of memory in MiB reserved in CMA for AMD-TEE driver
  

                                                                         driver.

Ack.

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•  Any amdtee shm buffer allocation larger than 64k will allocate memory from the CMA
  

                                                                                CMA.

Ack.

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•  The default can be overridden with the kernel commandline parameter "amdtee_cma".
  

\ No newline at end of file

Please fix that ^^^ warning.

Ack, as above. Thanks for the review.

Thanks.