Messages in this thread | | | From | David Laight <> | Subject | RE: [PATCHv4 3/3] x86/tdx: Handle load_unaligned_zeropad() page-cross to a shared page | Date | Thu, 16 Jun 2022 06:35:44 +0000 |
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From: Dave Hansen > Sent: 16 June 2022 00:35 > > On 6/15/22 15:52, Kirill A. Shutemov wrote: > >> + vaddr = (unsigned long)insn_get_addr_ref(&insn, regs); > >> + if (vaddr / PAGE_SIZE != (vaddr + size) / PAGE_SIZE) > > Oops. I just realized it has off-by-one. It supposed to be: > > > > if (vaddr / PAGE_SIZE != (vaddr + size - 1) / PAGE_SIZE) > > That was bugging me. Glad you caught this. > > Wouldn't this be more obviously correct? > > if (ALIGN_DOWN(vaddr, PAGE_SIZE) != > ALIGN_DOWN(vaddr + size, PAGE_SIZE)) > ... > > I don't think we have a PAGE_ALIGN_DOWN().
Or: if ((vaddr ^ (vaddr + size - 1)) >> PAGE_SHIFT)
David
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