Hi Christoffer,
On 4 June 2014 16:15, Christoffer Dall <christoffer.dall@xxxxxxxxxx> wrote:
> unmap_range() was utterly broken, to quote Marc, and broke in all sorts
> of situations. It was also quite complicated to follow and didn't
> follow the usual scheme of having a separate iterating function for each
> level of page tables.
>
> Address this by refactoring the code and introduce a pgd_clear()
> function.
>
> Tested on TC2 with/without THP and limited testing on the v8 Foundation
> Model.
>
> Reviewed-by: Jungseok Lee <jays.lee@xxxxxxxxxxx>
> Reviewed-by: Mario Smarduch <m.smarduch@xxxxxxxxxxx>
> Acked-by: Marc Zyngier <marc.zyngier@xxxxxxx>
> Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
> ---
This looks good to me.
Reviewed-by: Steve Capper <steve.capper@xxxxxxxxxx>
One minor comment below (sorry just spotted this now)...
[ ... ]
> -static void clear_pte_entry(struct kvm *kvm, pte_t *pte, phys_addr_t addr)
> +static void unmap_ptes(struct kvm *kvm, pmd_t *pmd,
> + phys_addr_t addr, phys_addr_t end)
> {
> - if (pte_present(*pte)) {
> - kvm_set_pte(pte, __pte(0));
> - put_page(virt_to_page(pte));
> - kvm_tlb_flush_vmid_ipa(kvm, addr);
> - }
> + pte_t *pte, *start_pte;
> + unsigned long long start_addr = addr;
> +
> + start_pte = pte = pte_offset_kernel(pmd, addr);
> + do {
> + if (!pte_none(*pte)) {
> + kvm_set_pte(pte, __pte(0));
> + put_page(virt_to_page(pte));
> + kvm_tlb_flush_vmid_ipa(kvm, addr);
Can this hyp call be expensive if a lot of ptes are being unmapped
(for 64K pages we can have 8192 ptes per page)?
If so, can they be batched together?
Cheers,
--
Steve
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