Register to .numa_protect() callback in mmu notifier so that KVM can get
acurate information about when a page is PROT_NONE protected in primary
MMU and unmap it in secondary MMU accordingly.
In KVM's .invalidate_range_start() handler, if the event is to notify that
the range may be protected to PROT_NONE for NUMA migration purpose,
don't do the unmapping in secondary MMU. Hold on until.numa_protect()
comes.
Signed-off-by: Yan Zhao <yan.y.zhao@xxxxxxxxx>
---
virt/kvm/kvm_main.c | 25 ++++++++++++++++++++++---
1 file changed, 22 insertions(+), 3 deletions(-)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index dfbaafbe3a00..907444a1761b 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -711,6 +711,20 @@ static void kvm_mmu_notifier_change_pte(struct mmu_notifier *mn,
kvm_handle_hva_range(mn, address, address + 1, pte, kvm_change_spte_gfn);
}
+static void kvm_mmu_notifier_numa_protect(struct mmu_notifier *mn,
+ struct mm_struct *mm,
+ unsigned long start,
+ unsigned long end)
+{
+ struct kvm *kvm = mmu_notifier_to_kvm(mn);
+
+ WARN_ON_ONCE(!READ_ONCE(kvm->mn_active_invalidate_count));
+ if (!READ_ONCE(kvm->mmu_invalidate_in_progress))
+ return;
+
+ kvm_handle_hva_range(mn, start, end, __pte(0), kvm_unmap_gfn_range);
+}
+
void kvm_mmu_invalidate_begin(struct kvm *kvm, unsigned long start,
unsigned long end)
{
@@ -744,14 +758,18 @@ static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
const struct mmu_notifier_range *range)
{
struct kvm *kvm = mmu_notifier_to_kvm(mn);
+ bool is_numa = (range->event == MMU_NOTIFY_PROTECTION_VMA) &&
+ (range->flags & MMU_NOTIFIER_RANGE_NUMA);
const struct kvm_hva_range hva_range = {
.start = range->start,
.end = range->end,
.pte = __pte(0),
- .handler = kvm_unmap_gfn_range,
+ .handler = !is_numa ? kvm_unmap_gfn_range :
+ (void *)kvm_null_fn,
.on_lock = kvm_mmu_invalidate_begin,
- .on_unlock = kvm_arch_guest_memory_reclaimed,
- .flush_on_ret = true,
+ .on_unlock = !is_numa ? kvm_arch_guest_memory_reclaimed :
+ (void *)kvm_null_fn,
+ .flush_on_ret = !is_numa ? true : false,
.may_block = mmu_notifier_range_blockable(range),
};
@@ -899,6 +917,7 @@ static const struct mmu_notifier_ops kvm_mmu_notifier_ops = {
.clear_young = kvm_mmu_notifier_clear_young,
.test_young = kvm_mmu_notifier_test_young,
.change_pte = kvm_mmu_notifier_change_pte,
+ .numa_protect = kvm_mmu_notifier_numa_protect,
.release = kvm_mmu_notifier_release,
};
--
2.17.1
