On Wed, Jul 09, 2014 at 04:12:53PM -0300, mtosatti@xxxxxxxxxx wrote:
> Reload remote vcpus MMU from GET_DIRTY_LOG codepath, before
> deleting a pinned spte.
>
> Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
>
> ---
> arch/x86/kvm/mmu.c | 29 +++++++++++++++++++++++------
> 1 file changed, 23 insertions(+), 6 deletions(-)
>
> Index: kvm.pinned-sptes/arch/x86/kvm/mmu.c
> ===================================================================
> --- kvm.pinned-sptes.orig/arch/x86/kvm/mmu.c 2014-07-09 11:23:59.290744490 -0300
> +++ kvm.pinned-sptes/arch/x86/kvm/mmu.c 2014-07-09 11:24:58.449632435 -0300
> @@ -1208,7 +1208,8 @@
> *
> * Return true if tlb need be flushed.
> */
> -static bool spte_write_protect(struct kvm *kvm, u64 *sptep, bool pt_protect)
> +static bool spte_write_protect(struct kvm *kvm, u64 *sptep, bool pt_protect,
> + bool skip_pinned)
> {
> u64 spte = *sptep;
>
> @@ -1218,6 +1219,22 @@
>
> rmap_printk("rmap_write_protect: spte %p %llx\n", sptep, *sptep);
>
> + if (is_pinned_spte(spte)) {
> + /* keep pinned spte intact, mark page dirty again */
> + if (skip_pinned) {
> + struct kvm_mmu_page *sp;
> + gfn_t gfn;
> +
> + sp = page_header(__pa(sptep));
> + gfn = kvm_mmu_page_get_gfn(sp, sptep - sp->spt);
> +
> + mark_page_dirty(kvm, gfn);
> + return false;
Why not mark all pinned gfns as dirty in kvm_vm_ioctl_get_dirty_log() while
populating dirty_bitmap_buffer?
> + } else
> + mmu_reload_pinned_vcpus(kvm);
Can you explain why do you need this?
> + }
> +
> +
> if (pt_protect)
> spte &= ~SPTE_MMU_WRITEABLE;
> spte = spte & ~PT_WRITABLE_MASK;
> @@ -1226,7 +1243,7 @@
> }
>
> static bool __rmap_write_protect(struct kvm *kvm, unsigned long *rmapp,
> - bool pt_protect)
> + bool pt_protect, bool skip_pinned)
> {
> u64 *sptep;
> struct rmap_iterator iter;
> @@ -1235,7 +1252,7 @@
> for (sptep = rmap_get_first(*rmapp, &iter); sptep;) {
> BUG_ON(!(*sptep & PT_PRESENT_MASK));
>
> - flush |= spte_write_protect(kvm, sptep, pt_protect);
> + flush |= spte_write_protect(kvm, sptep, pt_protect, skip_pinned);
> sptep = rmap_get_next(&iter);
> }
>
> @@ -1261,7 +1278,7 @@
> while (mask) {
> rmapp = __gfn_to_rmap(slot->base_gfn + gfn_offset + __ffs(mask),
> PT_PAGE_TABLE_LEVEL, slot);
> - __rmap_write_protect(kvm, rmapp, false);
> + __rmap_write_protect(kvm, rmapp, false, true);
>
> /* clear the first set bit */
> mask &= mask - 1;
> @@ -1280,7 +1297,7 @@
> for (i = PT_PAGE_TABLE_LEVEL;
> i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
> rmapp = __gfn_to_rmap(gfn, i, slot);
> - write_protected |= __rmap_write_protect(kvm, rmapp, true);
> + write_protected |= __rmap_write_protect(kvm, rmapp, true, false);
> }
>
> return write_protected;
> @@ -4565,7 +4582,7 @@
>
> for (index = 0; index <= last_index; ++index, ++rmapp) {
> if (*rmapp)
> - __rmap_write_protect(kvm, rmapp, false);
> + __rmap_write_protect(kvm, rmapp, false, false);
>
> if (need_resched() || spin_needbreak(&kvm->mmu_lock))
> cond_resched_lock(&kvm->mmu_lock);
>
>
--
Gleb.
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