Messages in this thread | | | Date | Thu, 3 Aug 2023 14:45:46 +0300 | From | "" <> | Subject | Re: [PATCH v3 07/12] x86/tdx: Make TDX_HYPERCALL asm similar to TDX_MODULE_CALL |
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On Thu, Jul 27, 2023 at 11:05:35PM +0000, Huang, Kai wrote: > On Thu, 2023-07-27 at 20:10 +0300, kirill.shutemov@linux.intel.com wrote: > > On Wed, Jul 26, 2023 at 11:25:09PM +1200, Kai Huang wrote: > > > > > > Remove the __tdx_hypercall_ret() as __tdx_hypercall() already does so. > > > > Hm. So we now update struct on all VMCALLs. Is it a good idea? > > > > Do you mean we "unconditionally save output registers to the structure", right? > > > We give > > more control to VMM where it is not needed. > > > > I don't quite follow this. Can you elaborate? > > Do you worry about VMM being malicious and putting malicious values to the > registers?
Yes. Caller of the hypercall may expect that the register is in-only and re-use the field for other stuff. And it would work until VMM decide otherwise.
> > I would rather keep the struct > > read-only where possible. > > > > We can achieve this if there's a clean way to do, but I don't see that.
Keep _ret() and non-_ret() versions?
-- Kiryl Shutsemau / Kirill A. Shutemov
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