From: Ben Gardon <bgardon@google.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: Paolo Bonzini <pbonzini@redhat.com>, Peter Xu <peterx@redhat.com>,
Sean Christopherson <seanjc@google.com>,
Peter Shier <pshier@google.com>,
Peter Feiner <pfeiner@google.com>,
Junaid Shahid <junaids@google.com>,
Jim Mattson <jmattson@google.com>,
Yulei Zhang <yulei.kernel@gmail.com>,
Wanpeng Li <kernellwp@gmail.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Xiao Guangrong <xiaoguangrong.eric@gmail.com>,
Ben Gardon <bgardon@google.com>
Subject: [PATCH v2 10/13] KVM: x86/mmu: Allow zapping collapsible SPTEs to use MMU read lock
Date: Thu, 1 Apr 2021 16:37:33 -0700 [thread overview]
Message-ID: <20210401233736.638171-11-bgardon@google.com> (raw)
In-Reply-To: <20210401233736.638171-1-bgardon@google.com>
To speed the process of disabling dirty logging, change the TDP MMU
function which zaps collapsible SPTEs to run under the MMU read lock.
Signed-off-by: Ben Gardon <bgardon@google.com>
---
arch/x86/kvm/mmu/mmu.c | 14 ++++++++++----
arch/x86/kvm/mmu/tdp_mmu.c | 17 +++++++++++++----
2 files changed, 23 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index d03a7a8b7ea2..5939813e3043 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5612,13 +5612,19 @@ void kvm_mmu_zap_collapsible_sptes(struct kvm *kvm,
write_lock(&kvm->mmu_lock);
flush = slot_handle_leaf(kvm, slot, kvm_mmu_zap_collapsible_spte, true);
- if (is_tdp_mmu_enabled(kvm))
- flush = kvm_tdp_mmu_zap_collapsible_sptes(kvm, slot, flush);
-
if (flush)
kvm_arch_flush_remote_tlbs_memslot(kvm, slot);
-
write_unlock(&kvm->mmu_lock);
+
+ if (is_tdp_mmu_enabled(kvm)) {
+ flush = false;
+
+ read_lock(&kvm->mmu_lock);
+ flush = kvm_tdp_mmu_zap_collapsible_sptes(kvm, slot, flush);
+ if (flush)
+ kvm_arch_flush_remote_tlbs_memslot(kvm, slot);
+ read_unlock(&kvm->mmu_lock);
+ }
}
void kvm_arch_flush_remote_tlbs_memslot(struct kvm *kvm,
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 6917403484ce..0e6ffa04e5e1 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -1323,7 +1323,8 @@ static bool zap_collapsible_spte_range(struct kvm *kvm,
rcu_read_lock();
tdp_root_for_each_pte(iter, root, start, end) {
- if (tdp_mmu_iter_cond_resched(kvm, &iter, flush, false)) {
+retry:
+ if (tdp_mmu_iter_cond_resched(kvm, &iter, flush, true)) {
flush = false;
continue;
}
@@ -1338,8 +1339,14 @@ static bool zap_collapsible_spte_range(struct kvm *kvm,
pfn, PG_LEVEL_NUM))
continue;
- tdp_mmu_set_spte(kvm, &iter, 0);
-
+ if (!tdp_mmu_zap_spte_atomic(kvm, &iter)) {
+ /*
+ * The iter must explicitly re-read the SPTE because
+ * the atomic cmpxchg failed.
+ */
+ iter.old_spte = READ_ONCE(*rcu_dereference(iter.sptep));
+ goto retry;
+ }
flush = true;
}
@@ -1358,7 +1365,9 @@ bool kvm_tdp_mmu_zap_collapsible_sptes(struct kvm *kvm,
{
struct kvm_mmu_page *root;
- for_each_tdp_mmu_root_yield_safe(kvm, root, slot->as_id, false)
+ lockdep_assert_held_read(&kvm->mmu_lock);
+
+ for_each_tdp_mmu_root_yield_safe(kvm, root, slot->as_id, true)
flush = zap_collapsible_spte_range(kvm, root, slot, flush);
return flush;
--
2.31.0.208.g409f899ff0-goog
next prev parent reply other threads:[~2021-04-01 23:38 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-01 23:37 [PATCH v2 00/13] More parallel operations for the TDP MMU Ben Gardon
2021-04-01 23:37 ` [PATCH v2 01/13] KVM: x86/mmu: Re-add const qualifier in kvm_tdp_mmu_zap_collapsible_sptes Ben Gardon
2021-05-26 21:25 ` Sean Christopherson
2021-04-01 23:37 ` [PATCH v2 02/13] KVM: x86/mmu: Move kvm_mmu_(get|put)_root to TDP MMU Ben Gardon
2021-04-01 23:37 ` [PATCH v2 03/13] KVM: x86/mmu: use tdp_mmu_free_sp to free roots Ben Gardon
2021-04-01 23:37 ` [PATCH v2 04/13] KVM: x86/mmu: Merge TDP MMU put and free root Ben Gardon
2021-04-01 23:37 ` [PATCH v2 05/13] KVM: x86/mmu: Refactor yield safe root iterator Ben Gardon
2021-04-01 23:37 ` [PATCH v2 06/13] KVM: x86/mmu: Make TDP MMU root refcount atomic Ben Gardon
2021-04-01 23:37 ` [PATCH v2 07/13] KVM: x86/mmu: handle cmpxchg failure in kvm_tdp_mmu_get_root Ben Gardon
2021-04-01 23:37 ` [PATCH v2 08/13] KVM: x86/mmu: Protect the tdp_mmu_roots list with RCU Ben Gardon
2021-04-01 23:37 ` [PATCH v2 09/13] KVM: x86/mmu: Allow zap gfn range to operate under the mmu read lock Ben Gardon
2021-04-02 7:53 ` Paolo Bonzini
2021-04-12 18:21 ` Ben Gardon
2021-04-01 23:37 ` Ben Gardon [this message]
2021-04-02 11:14 ` [PATCH v2 10/13] KVM: x86/mmu: Allow zapping collapsible SPTEs to use MMU " Paolo Bonzini
2021-04-01 23:37 ` [PATCH v2 11/13] KVM: x86/mmu: Allow enabling / disabling dirty logging under " Ben Gardon
2021-04-01 23:37 ` [PATCH v2 12/13] KVM: x86/mmu: Fast invalidation for TDP MMU Ben Gardon
2021-04-01 23:37 ` [PATCH v2 13/13] KVM: x86/mmu: Tear down roots in fast invalidation thread Ben Gardon
2021-04-02 11:43 ` [PATCH v2 00/13] More parallel operations for the TDP MMU Paolo Bonzini
2021-05-26 21:34 ` Sean Christopherson
2021-05-27 11:41 ` Paolo Bonzini
2021-05-27 15:26 ` Sean Christopherson
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