Re: [PATCH v9 1/2] x86/tdx: Retry TDVMCALL_MAP_GPA() when needed

From: Xiaoyao Li
Date: Tue Jul 18 2023 - 22:31:20 EST


On 6/22/2023 3:13 AM, Dexuan Cui wrote:
GHCI spec for TDX 1.0 says that the MapGPA call may fail with the R10
error code = TDG.VP.VMCALL_RETRY (1), and the guest must retry this
operation for the pages in the region starting at the GPA specified
in R11.

When a fully enlightened TDX guest runs on Hyper-V, Hyper-V can return
the retry error when set_memory_decrypted() is called to decrypt up to
1GB of swiotlb bounce buffers.

just out of curiosity, what size does Hyper-v handle at most in one call?