On Fri, Jan 05, 2024 at 07:38:48PM +0000, Edgecombe, Rick P wrote:
> The break apart looks good.
>
> On Sat, 2023-12-23 at 02:52 +0300, Kirill A. Shutemov wrote:
> > + while (addr < end) {
> > + unsigned long size;
> > + unsigned int level;
> > + pte_t *pte;
> > +
> > + pte = lookup_address(addr, &level);
> > + size = page_level_size(level);
> > +
> > + if (pte && pte_decrypted(*pte)) {
> > + int pages = size / PAGE_SIZE;
> > +
> > + /*
> > + * Touching memory with shared bit set
> > triggers implicit
> > + * conversion to shared.
> > + *
> > + * Make sure nobody touches the shared range
> > from
> > + * now on.
> > + */
> > + set_pte(pte, __pte(0));
>
> Does this need a full shootdown at this point, at least in the crash
> case? A local flush for the non-crash case might be nice too.
See __flush_tlb_all() after the loop.
> Also, probably a barrier() between set_pte() and
> tdx_enc_status_changed().
But why? There's no concurrency at this point. Interrupts are disabled and
only one CPU is active. Nobody can touch the memory relevant for the PTE.
--
Kiryl Shutsemau / Kirill A. Shutemov
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