On 3/20/20 1:53 PM, David Rientjes wrote: >> + >> + /* Clear encryption flag and write new pte */ >> + pte = pte_clear_flags(*ptep, _PAGE_ENC); >> + set_pte(ptep, pte); >> + >> + /* Flush TLB to map the page unencrypted */ >> + write_cr3(top_level_pgt); >> + > Is there a guarantee that this flushes the tlb if cr3 == top_level_pgt > alrady without an invlpg? Ahh, good catch. It *never* flushes global pages. For a generic function like this, that seems pretty dangerous because the PTEs it goes after could quite easily be Global. It's also not _obviously_ correct if PCIDs are in play (which I don't think they are on AMD). A flush_tlb_global() is probably more appropriate. Better yet, is there a reason not to use flush_tlb_kernel_range()? I don't think it's necessary to whack the entire TLB for one PTE set.
