On Wed, Jun 18, 2014 at 08:12:06PM -0300, mtosatti@xxxxxxxxxx wrote:
> Request KVM_REQ_MMU_RELOAD when deleting sptes from MMU notifiers.
>
> Keep pinned sptes intact if page aging.
>
> Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
>
> ---
> arch/x86/kvm/mmu.c | 71 ++++++++++++++++++++++++++++++++++++++++++++++-------
> 1 file changed, 62 insertions(+), 9 deletions(-)
>
> Index: kvm.pinned-sptes/arch/x86/kvm/mmu.c
> ===================================================================
> --- kvm.pinned-sptes.orig/arch/x86/kvm/mmu.c 2014-06-18 17:28:24.339435654 -0300
> +++ kvm.pinned-sptes/arch/x86/kvm/mmu.c 2014-06-18 17:29:32.510225755 -0300
> @@ -1184,6 +1184,42 @@
> kvm_flush_remote_tlbs(vcpu->kvm);
> }
>
> +static void ack_flush(void *_completed)
> +{
> +}
> +
> +static void mmu_reload_pinned_vcpus(struct kvm *kvm)
> +{
> + int i, cpu, me;
> + cpumask_var_t cpus;
> + struct kvm_vcpu *vcpu;
> + unsigned int req = KVM_REQ_MMU_RELOAD;
> +
> + zalloc_cpumask_var(&cpus, GFP_ATOMIC);
> +
> + me = get_cpu();
> + kvm_for_each_vcpu(i, vcpu, kvm) {
> + if (list_empty(&vcpu->arch.pinned_mmu_pages))
> + continue;
> + kvm_make_request(req, vcpu);
> + cpu = vcpu->cpu;
> +
> + /* Set ->requests bit before we read ->mode */
> + smp_mb();
> +
> + if (cpus != NULL && cpu != -1 && cpu != me &&
> + kvm_vcpu_exiting_guest_mode(vcpu) != OUTSIDE_GUEST_MODE)
> + cpumask_set_cpu(cpu, cpus);
> + }
> + if (unlikely(cpus == NULL))
> + smp_call_function_many(cpu_online_mask, ack_flush, NULL, 1);
> + else if (!cpumask_empty(cpus))
> + smp_call_function_many(cpus, ack_flush, NULL, 1);
> + put_cpu();
> + free_cpumask_var(cpus);
> + return;
> +}
This is a c&p of make_all_cpus_request(), the only difference is checking
of vcpu->arch.pinned_mmu_pages. You can add make_some_cpus_request(..., bool (*predicate)(struct kvm_vcpu *))
to kvm_main.c and rewrite make_all_cpus_request() to use it instead.
> +
> /*
> * Write-protect on the specified @sptep, @pt_protect indicates whether
> * spte write-protection is caused by protecting shadow page table.
> @@ -1276,7 +1312,8 @@
> }
>
> static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp,
> - struct kvm_memory_slot *slot, unsigned long data)
> + struct kvm_memory_slot *slot, unsigned long data,
> + bool age)
> {
> u64 *sptep;
> struct rmap_iterator iter;
> @@ -1286,6 +1323,14 @@
> BUG_ON(!(*sptep & PT_PRESENT_MASK));
> rmap_printk("kvm_rmap_unmap_hva: spte %p %llx\n", sptep, *sptep);
>
> + if (is_pinned_spte(*sptep)) {
> + /* don't nuke pinned sptes if page aging: return
> + * young=yes instead.
> + */
> + if (age)
> + return 1;
> + mmu_reload_pinned_vcpus(kvm);
> + }
> drop_spte(kvm, sptep);
> need_tlb_flush = 1;
> }
> @@ -1294,7 +1339,8 @@
> }
>
> static int kvm_set_pte_rmapp(struct kvm *kvm, unsigned long *rmapp,
> - struct kvm_memory_slot *slot, unsigned long data)
> + struct kvm_memory_slot *slot, unsigned long data,
> + bool age)
> {
> u64 *sptep;
> struct rmap_iterator iter;
> @@ -1312,6 +1358,9 @@
>
> need_flush = 1;
>
> + if (is_pinned_spte(*sptep))
> + mmu_reload_pinned_vcpus(kvm);
> +
> if (pte_write(*ptep)) {
> drop_spte(kvm, sptep);
> sptep = rmap_get_first(*rmapp, &iter);
> @@ -1342,7 +1391,8 @@
> int (*handler)(struct kvm *kvm,
> unsigned long *rmapp,
> struct kvm_memory_slot *slot,
> - unsigned long data))
> + unsigned long data,
> + bool age))
> {
> int j;
> int ret = 0;
> @@ -1382,7 +1432,7 @@
> rmapp = __gfn_to_rmap(gfn_start, j, memslot);
>
> for (; idx <= idx_end; ++idx)
> - ret |= handler(kvm, rmapp++, memslot, data);
> + ret |= handler(kvm, rmapp++, memslot, data, false);
> }
> }
>
> @@ -1393,7 +1443,8 @@
> unsigned long data,
> int (*handler)(struct kvm *kvm, unsigned long *rmapp,
> struct kvm_memory_slot *slot,
> - unsigned long data))
> + unsigned long data,
> + bool age))
> {
> return kvm_handle_hva_range(kvm, hva, hva + 1, data, handler);
> }
> @@ -1414,7 +1465,8 @@
> }
>
> static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
> - struct kvm_memory_slot *slot, unsigned long data)
> + struct kvm_memory_slot *slot, unsigned long data,
> + bool age)
> {
> u64 *sptep;
> struct rmap_iterator uninitialized_var(iter);
> @@ -1429,7 +1481,7 @@
> * out actively used pages or breaking up actively used hugepages.
> */
> if (!shadow_accessed_mask) {
> - young = kvm_unmap_rmapp(kvm, rmapp, slot, data);
> + young = kvm_unmap_rmapp(kvm, rmapp, slot, data, true);
> goto out;
> }
>
> @@ -1450,7 +1502,8 @@
> }
>
> static int kvm_test_age_rmapp(struct kvm *kvm, unsigned long *rmapp,
> - struct kvm_memory_slot *slot, unsigned long data)
> + struct kvm_memory_slot *slot, unsigned long data,
> + bool age)
> {
> u64 *sptep;
> struct rmap_iterator iter;
> @@ -1488,7 +1541,7 @@
>
> rmapp = gfn_to_rmap(vcpu->kvm, gfn, sp->role.level);
>
> - kvm_unmap_rmapp(vcpu->kvm, rmapp, NULL, 0);
> + kvm_unmap_rmapp(vcpu->kvm, rmapp, NULL, 0, false);
> kvm_flush_remote_tlbs(vcpu->kvm);
> }
>
>
>
--
Gleb.
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