On Fri, 2024-09-06 at 16:36 -0700, Dan Williams wrote: > How about: > > Subject: x86/virt/tdx: Require the module to assert it has the NO_RBP_MOD mitigation > > ...to avoid the double negative. Will do. Thanks. > > Kai Huang wrote: > > Old TDX modules can clobber RBP in the TDH.VP.ENTER SEAMCALL. However > > RBP is used as frame pointer in the x86_64 calling convention, and > > clobbering RBP could result in bad things like being unable to unwind > > the stack if any non-maskable exceptions (NMI, #MC etc) happens in that > > gap. > > > > A new "NO_RBP_MOD" feature was introduced to more recent TDX modules to > > not clobber RBP. This feature is reported in the TDX_FEATURES0 global > > metadata field via bit 18. > > > > Don't initialize the TDX module if this feature is not supported [1]. > > > > Link: https://lore.kernel.org/all/c0067319-2653-4cbd-8fee-1ccf21b1e646@xxxxxxxx/T/#mef98469c51e2382ead2c537ea189752360bd2bef [1] > > Trim this to the direct message-id format, but otherwise: Will do. If I got it right, the link with message-id should be: https://lore.kernel.org/all/fc0e8ab7-86d4-4428-be31-82e1ece6dd21@xxxxxxxxx/ > > Reviewed-by: Dan Williams <dan.j.williams@xxxxxxxxx> Thanks.
