Messages in this thread | | | Date | Fri, 17 May 2024 09:34:56 -0700 | Subject | Re: [PATCH] x86/kvm/tdx: Save %rbp in TDX_MODULE_CALL | From | Dave Hansen <> |
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On 5/17/24 09:12, Sean Christopherson wrote: >> There's a feature in TDX module 1.5 that prevents RBP modification across >> TDH.VP.ENTER SEAMCALL. See NO_RBP_MOD in TDX Module 1.5 ABI spec. > LOL, "feature". How was clobbering RBP not treated as a bug? I'm party joking, > but also quite serious.
I'm on the same page. It would have been far simpler for all involved to retroactively say that modifying RBP is against the rules and any module that does it is buggy. Get a new module if yours is buggy.
I _believe_ the intent was to support guest/host combinations that used RBP for whatever reason. But I'm not sure such a combination exists or ever existed in practice.
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