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. -- Sathyanarayanan Kuppuswamy Linux Kernel Developer
