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Message-ID: <20230627042639.12636-1-likexu@tencent.com>
Date: Tue, 27 Jun 2023 12:26:39 +0800
From: Like Xu <like.xu.linux@...il.com>
To: Sean Christopherson <seanjc@...gle.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH] KVM: x86/mmu: Move the lockdep_assert of mmu_lock to inside clear_dirty_pt_masked()
From: Like Xu <likexu@...cent.com>
Move the lockdep_assert_held_write(&kvm->mmu_lock) from the only one caller
kvm_tdp_mmu_clear_dirty_pt_masked() to inside clear_dirty_pt_masked().
This change makes it more obvious why it's safe for clear_dirty_pt_masked()
to use the non-atomic (for non-volatile SPTEs) tdp_mmu_clear_spte_bits()
helper. for_each_tdp_mmu_root() does its own lockdep, so the only "loss"
in lockdep coverage is if the list is completely empty.
Suggested-by: Sean Christopherson <seanjc@...gle.com>
Signed-off-by: Like Xu <likexu@...cent.com>
---
arch/x86/kvm/mmu/tdp_mmu.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 512163d52194..0b4f03bef70e 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -1600,6 +1600,8 @@ static void clear_dirty_pt_masked(struct kvm *kvm, struct kvm_mmu_page *root,
shadow_dirty_mask;
struct tdp_iter iter;
+ lockdep_assert_held_write(&kvm->mmu_lock);
+
rcu_read_lock();
tdp_root_for_each_leaf_pte(iter, root, gfn + __ffs(mask),
@@ -1646,7 +1648,6 @@ void kvm_tdp_mmu_clear_dirty_pt_masked(struct kvm *kvm,
{
struct kvm_mmu_page *root;
- lockdep_assert_held_write(&kvm->mmu_lock);
for_each_tdp_mmu_root(kvm, root, slot->as_id)
clear_dirty_pt_masked(kvm, root, gfn, mask, wrprot);
}
base-commit: 88bb466c9dec4f70d682cf38c685324e7b1b3d60
--
2.41.0
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