+ Kirill. On Wed, Feb 09, 2022 at 12:10:15PM -0600, Brijesh Singh wrote: > @@ -2012,8 +2013,22 @@ static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc) > */ > cpa_flush(&cpa, !this_cpu_has(X86_FEATURE_SME_COHERENT)); > > + /* > + * To maintain the security guarantees of SEV-SNP guests, make sure > + * to invalidate the memory before clearing the encryption attribute. > + */ > + if (!enc) > + snp_set_memory_shared(addr, numpages); > + > ret = __change_page_attr_set_clr(&cpa, 1); > > + /* > + * Now that memory is mapped encrypted in the page table, validate it > + * so that it is consistent with the above page state. > + */ > + if (!ret && enc) > + snp_set_memory_private(addr, numpages); > + > /* > * After changing the encryption attribute, we need to flush TLBs again > * in case any speculative TLB caching occurred (but no need to flush > -- Right, as tglx rightfully points out here: https://lore.kernel.org/r/875ypyvz07.ffs@tglx this piece of code needs careful coordinated design so that it is clean for both SEV and TDX. First, as we've said here: https://lore.kernel.org/r/1d77e91c-e151-7846-6cd4-6264236ca5ae@xxxxxxxxx we'd need generic functions which turn a pgprot into an encrypted or decrypted pgprot on both SEV and TDX so we could do: cc_pgprot_enc() cc_pgprot_dec() which does the required conversion on each guest type. Also, I think adding required functions to x86_platform.guest. is a very nice way to solve the ugly if (guest_type) querying all over the place. Also, I was thinking of sme_me_mask and the corresponding tdx_shared_mask I threw into the mix here: https://lore.kernel.org/r/YgFIaJ8ijgQQ04Nv@xxxxxxx and we should simply add those without ifdeffery but unconditionally. 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? -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette
