Convert kvm_unmap_gfn_range(), which is the helper that zaps rmap SPTEs in
response to an mmu_notifier invalidation, to use __kvm_rmap_zap_gfn_range()
and feed in range->may_block. In other words, honor NEED_RESCHED by way of
cond_resched() when zapping rmaps. This fixes a long-standing issue where
KVM could process an absurd number of rmap entries without ever yielding,
e.g. if an mmu_notifier fired on a PUD (or larger) range.
Opportunistically rename __kvm_zap_rmap() to kvm_zap_rmap(), and drop the
old kvm_zap_rmap(). Ideally, the shuffling would be done in a different
patch, but that just makes the compiler unhappy, e.g.
arch/x86/kvm/mmu/mmu.c:1462:13: error: ‘kvm_zap_rmap’ defined but not used
Reported-by: Peter Xu <peterx@xxxxxxxxxx>
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/mmu/mmu.c | 16 ++++++----------
1 file changed, 6 insertions(+), 10 deletions(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 4016f63d03e8..0a33857d668a 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -1453,16 +1453,10 @@ static bool kvm_vcpu_write_protect_gfn(struct kvm_vcpu *vcpu, u64 gfn)
return kvm_mmu_slot_gfn_write_protect(vcpu->kvm, slot, gfn, PG_LEVEL_4K);
}
-static bool __kvm_zap_rmap(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
- const struct kvm_memory_slot *slot)
-{
- return kvm_zap_all_rmap_sptes(kvm, rmap_head);
-}
-
static bool kvm_zap_rmap(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
- struct kvm_memory_slot *slot, gfn_t gfn, int level)
+ const struct kvm_memory_slot *slot)
{
- return __kvm_zap_rmap(kvm, rmap_head, slot);
+ return kvm_zap_all_rmap_sptes(kvm, rmap_head);
}
struct slot_rmap_walk_iterator {
@@ -1597,7 +1591,7 @@ static bool __kvm_rmap_zap_gfn_range(struct kvm *kvm,
gfn_t start, gfn_t end, bool can_yield,
bool flush)
{
- return __walk_slot_rmaps(kvm, slot, __kvm_zap_rmap,
+ return __walk_slot_rmaps(kvm, slot, kvm_zap_rmap,
PG_LEVEL_4K, KVM_MAX_HUGEPAGE_LEVEL,
start, end - 1, can_yield, true, flush);
}
@@ -1626,7 +1620,9 @@ bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range)
bool flush = false;
if (kvm_memslots_have_rmaps(kvm))
- flush = kvm_handle_gfn_range(kvm, range, kvm_zap_rmap);
+ flush = __kvm_rmap_zap_gfn_range(kvm, range->slot,
+ range->start, range->end,
+ range->may_block, flush);
if (tdp_mmu_enabled)
flush = kvm_tdp_mmu_unmap_gfn_range(kvm, range, flush);
--
2.46.0.76.ge559c4bf1a-goog
