On 20/11/2015 09:47, Takuya Yoshikawa wrote:
> kvm_mmu_mark_parents_unsync() alone uses pte_list_walk(), witch does
> nearly the same as the for_each_rmap_spte macro. The only difference
> is that is_shadow_present_pte() checks cannot be placed there because
> kvm_mmu_mark_parents_unsync() can be called with a new parent pointer
> whose entry is not set yet.
>
> By calling mark_unsync() separately for the parent and adding the parent
> pointer to the parent_ptes chain later in kvm_mmu_get_page(), the macro
> works with no problem.
>
> Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@xxxxxxxxxxxxx>
> ---
> arch/x86/kvm/mmu.c | 36 +++++++++++++-----------------------
> 1 file changed, 13 insertions(+), 23 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index 7f46e3e..4e29d9a 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -1007,26 +1007,6 @@ static void pte_list_remove(u64 *spte, struct kvm_rmap_head *rmap_head)
> }
> }
>
> -typedef void (*pte_list_walk_fn) (u64 *spte);
> -static void pte_list_walk(struct kvm_rmap_head *rmap_head, pte_list_walk_fn fn)
> -{
> - struct pte_list_desc *desc;
> - int i;
> -
> - if (!rmap_head->val)
> - return;
> -
> - if (!(rmap_head->val & 1))
> - return fn((u64 *)rmap_head->val);
> -
> - desc = (struct pte_list_desc *)(rmap_head->val & ~1ul);
> - while (desc) {
> - for (i = 0; i < PTE_LIST_EXT && desc->sptes[i]; ++i)
> - fn(desc->sptes[i]);
> - desc = desc->more;
> - }
> -}
> -
> static struct kvm_rmap_head *__gfn_to_rmap(gfn_t gfn, int level,
> struct kvm_memory_slot *slot)
> {
> @@ -1749,7 +1729,12 @@ static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, int direct
> static void mark_unsync(u64 *spte);
> static void kvm_mmu_mark_parents_unsync(struct kvm_mmu_page *sp)
> {
> - pte_list_walk(&sp->parent_ptes, mark_unsync);
> + u64 *sptep;
> + struct rmap_iterator iter;
> +
> + for_each_rmap_spte(&sp->parent_ptes, &iter, sptep) {
> + mark_unsync(sptep);
> + }
> }
>
> static void mark_unsync(u64 *spte)
> @@ -2119,12 +2104,17 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
> if (sp->unsync && kvm_sync_page_transient(vcpu, sp))
> break;
>
> - mmu_page_add_parent_pte(vcpu, sp, parent_pte);
> if (sp->unsync_children) {
> kvm_make_request(KVM_REQ_MMU_SYNC, vcpu);
> kvm_mmu_mark_parents_unsync(sp);
> - } else if (sp->unsync)
> + if (parent_pte)
> + mark_unsync(parent_pte);
> + } else if (sp->unsync) {
> kvm_mmu_mark_parents_unsync(sp);
> + if (parent_pte)
> + mark_unsync(parent_pte);
> + }
> + mmu_page_add_parent_pte(vcpu, sp, parent_pte);
This patch is okay with Xiao's suggestion to remove the
kvm_mmu_mark_parents_unsync call.
Paolo
> __clear_sp_write_flooding_count(sp);
> trace_kvm_mmu_get_page(sp, false);
>
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