Messages in this thread | | | Date | Thu, 21 Jul 2022 10:02:05 -0700 | Subject | Re: [PATCH v8 5/5] x86/tdx: Add Quote generation support | From | Dave Hansen <> |
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On 7/21/22 09:54, Sathyanarayanan Kuppuswamy wrote: > > On 7/21/22 9:49 AM, Dave Hansen wrote: >> On 7/21/22 09:42, Sathyanarayanan Kuppuswamy wrote: >>> On 7/21/22 9:08 AM, Dave Hansen wrote: >>>> On 6/8/22 19:52, Kuppuswamy Sathyanarayanan wrote: >>>>> For shared buffer allocation, alternatives like using the DMA API is >>>>> also considered. Although it simpler to use, it is not preferred because >>>>> dma_alloc_*() APIs require a valid bus device as argument, which would >>>>> need converting the attestation driver into a platform device driver. >>>>> This is unnecessary, and since the attestation driver does not do real >>>>> DMA, there is no need to use real DMA APIs. >>>> Let's actually try to walk through the requirements for the memory >>>> allocation here. >>>> >>>> 1. The guest kernel needs to allocate some guest physical memory >>>> for the attestation data buffer >>> Physically contiguous memory. >> Remind me how large the quote structures are. > It depends on the attestation service. In addition to TDREPORT (1K size), > during quote generation, additional data can be included in the signed > quote. So the spec allows variable length. User agent will communicate with > attestation service to identify the appropriate buffer length. Our test > uses 8K buffers
What is this "additional data"? Is that "REPORTDATA" from the TDX module spec?
"Additional REPORTDATA, a 64-byte value, is provided by the guest TD to be included in the TDG.MR.REPORT."
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