On Sun, Feb 13, 2022 at 01:15:23PM +0100, Borislav Petkov wrote: > On Fri, Feb 11, 2022 at 11:27:54AM -0600, Brijesh Singh wrote: > > > Simply have them always present. They will have !0 values on the > > > respective guest types and 0 otherwise. This should simplify a lot of > > > code and another unconditionally present u64 won't be the end of the > > > world. > > > > > > Any other aspect I'm missing? > > > > I think that's mostly about it. IIUC, the recommendation is to define a > > new callback in x86_platform_op. The callback will be invoked > > unconditionally; The default implementation for this callback is NOP; > > The TDX and SEV will override with the platform specific implementation. > > I think we may able to handle everything in one callback hook but having > > pre and post will be a more desirable. Here is why I am thinking so: > > > > * On SNP, the page must be invalidated before clearing the _PAGE_ENC > > from the page table attribute > > > > * On SNP, the page must be validated after setting the _PAGE_ENC in the > > page table attribute. > > Right, we could have a pre- and post- callback, if that would make > things simpler/clearer. > > Also, in thinking further about the encryption mask, we could make it a > *single*, *global* variable called cc_mask which each guest type sets it > as it wants to. I don't think it works. TDX and SME/SEV has opposite polarity of the mask. SME/SEV has to clear the mask to share the page. TDX has to set it. Making a single global mask only increases confusion. -- Kirill A. Shutemov
