linux-kernel - [PATCH 23/28] KVM: x86/mmu: Use "zap root" path for "slow" zap of all TDP MMU SPTEs

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Date:   Sat, 20 Nov 2021 04:50:41 +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 23/28] KVM: x86/mmu: Use "zap root" path for "slow" zap of all
 TDP MMU SPTEs

Now that the "slow" zap of all TDP MMU SPTEs doesn't flush the TLBs, use
the dedicated "zap root" helper, which can be used if and only if a flush
isn't needed.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/mmu/tdp_mmu.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index e5401f0efe8e..99ea19e763da 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -888,6 +888,7 @@ bool __kvm_tdp_mmu_zap_gfn_range(struct kvm *kvm, int as_id, gfn_t start,
 
 void kvm_tdp_mmu_zap_all(struct kvm *kvm)
 {
+	struct kvm_mmu_page *root;
 	int i;
 
 	/*
@@ -895,8 +896,10 @@ void kvm_tdp_mmu_zap_all(struct kvm *kvm)
 	 * is being destroyed or the userspace VMM has exited.  In both cases,
 	 * KVM_RUN is unreachable, i.e. no vCPUs will ever service the request.
 	 */
-	for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++)
-		(void)kvm_tdp_mmu_zap_gfn_range(kvm, i, 0, -1ull, false);
+	for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
+		for_each_tdp_mmu_root_yield_safe(kvm, root, i, false)
+			(void)tdp_mmu_zap_root(kvm, root, false);
+	}
 }
 
 /*
-- 
2.34.0.rc2.393.gf8c9666880-goog