On 9/14/22 9:12 AM, Dave Hansen wrote:
On 9/14/22 08:36, Sathyanarayanan Kuppuswamy wrote:
When we initially submitted the attestation patches, virt/coco folder was not created. I initially kept this driver in platform/x86/, but later moved to arch/x86/coco based on the review comments in v4. There was a discussion about the need for a new config and the location of the driver. The outcome of that discussion is, since this is not a traditional driver, but a basic TDX feature, we don't need a special config and the code can be maintained in the arch/x86/coco folder.
Could you please include the following in this set somewhere:
"The code to do the SEV analog of this TDX functionality is in ___insert_path_here____. This code is different from that because ______reason______ so it is instead placed in ____other_path____."
?
I have also included info about why we don't use a separate config option for it.
The code for the SEV equivalent of this TDX attestation functionality can be found in drivers/virt/coco/sev-guest/. It is implemented as a platform module driver, and it can be enabled using the CONFIG_SEV_GUEST config option. However, in the case of TDX, it is implemented as a built-in driver in the arch/x86/coco/tdx/tdx.c because of the following reasons:
1. Attestation is expected to be needed by all distributions that support TDX. Therefore, using a separate configuration option is not necessary. With TDX support, it can be enabled by default, and a built-in driver model will work better in this use case. 2. Since it is not a conventional device driver and the code is very simple, creating an individual driver for it may be an overkill.