linux-kernel - [PATCH 21/28] KVM: x86/mmu: Add TDP MMU helper to zap a root

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Message-Id: <20211120045046.3940942-22-seanjc@google.com>
Date:   Sat, 20 Nov 2021 04:50:39 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Hou Wenlong <houwenlong93@...ux.alibaba.com>,
        Ben Gardon <bgardon@...gle.com>
Subject: [PATCH 21/28] KVM: x86/mmu: Add TDP MMU helper to zap a root

Add a small wrapper to handle zapping a specific root.  For now, it's
little more than syntactic sugar, but in the future it will become a
unique flow with rules specific to zapping an unreachable root.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/mmu/tdp_mmu.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 9449cb5baf0b..31fb622249e5 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -79,11 +79,18 @@ static void tdp_mmu_free_sp_rcu_callback(struct rcu_head *head)
 	tdp_mmu_free_sp(sp);
 }
 
+static bool tdp_mmu_zap_root(struct kvm *kvm, struct kvm_mmu_page *root,
+			     bool shared)
+{
+	return zap_gfn_range(kvm, root, 0, -1ull, true, false, shared);
+}
+
 /*
  * Note, putting a root might sleep, i.e. the caller must have IRQs enabled and
  * must not explicitly disable preemption (it will be disabled by virtue of
  * holding mmu_lock, hence the lack of a might_sleep()).
  */
+
 void kvm_tdp_mmu_put_root(struct kvm *kvm, struct kvm_mmu_page *root,
 			  bool shared)
 {
@@ -118,7 +125,7 @@ void kvm_tdp_mmu_put_root(struct kvm *kvm, struct kvm_mmu_page *root,
 	 * should have been zapped by kvm_tdp_mmu_zap_invalidated_roots(), and
 	 * inserting new SPTEs under an invalid root is a KVM bug.
 	 */
-	if (zap_gfn_range(kvm, root, 0, -1ull, true, false, shared))
+	if (tdp_mmu_zap_root(kvm, root, shared))
 		WARN_ON_ONCE(root->role.invalid);
 
 	call_rcu(&root->rcu_head, tdp_mmu_free_sp_rcu_callback);
@@ -923,7 +930,7 @@ void kvm_tdp_mmu_zap_invalidated_roots(struct kvm *kvm,
 		 * will still flush on yield, but that's a minor performance
 		 * blip and not a functional issue.
 		 */
-		(void)zap_gfn_range(kvm, root, 0, -1ull, true, false, true);
+		(void)tdp_mmu_zap_root(kvm, root, true);
 		kvm_tdp_mmu_put_root(kvm, root, true);
 	}
 }
-- 
2.34.0.rc2.393.gf8c9666880-goog