[EMAIL PROTECTED] wrote:
> +/* We walk down the guest page tables to get a guest-physical address */
> +unsigned long guest_pa(struct lguest *lg, unsigned long vaddr)
> +{
> +     pgd_t gpgd;
> +     pte_t gpte;
> +
> +     /* First step: get the top-level Guest page table entry. */
> +     gpgd = __pgd(lgread_u32(lg, gpgd_addr(lg, vaddr)));
> +     /* Toplevel not present?  We can't map it in. */
> +     if (!(pgd_flags(gpgd) & _PAGE_PRESENT))
> +             kill_guest(lg, "Bad address %#lx", vaddr);
> +
> +     gpte = __pte(lgread_u32(lg, gpte_addr(lg, gpgd, vaddr)));
> +     if (!(pte_flags(gpte) & _PAGE_PRESENT))
> +             kill_guest(lg, "Bad address %#lx", vaddr);
> +
> +     return pte_pfn(gpte) * PAGE_SIZE | (vaddr & ~PAGE_MASK);
> +}

That's nice and general, but is it necessary?  Is this just to handle
the two cases of booting with P=V, then switching to the normal kernel
offset?

    J
_______________________________________________
Virtualization mailing list
[email protected]
https://lists.linux-foundation.org/mailman/listinfo/virtualization

Reply via email to