linux-kernel - [PATCH 10/12] KVM: X86/MMU: Don't add parents to struct kvm_mmu

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Date:   Sun,  5 Jun 2022 14:43:40 +0800
From:   Lai Jiangshan <jiangshanlai@...il.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Maxim Levitsky <mlevitsk@...hat.com>,
        Lai Jiangshan <jiangshan.ljs@...group.com>
Subject: [PATCH 10/12] KVM: X86/MMU: Don't add parents to struct kvm_mmu_pages

From: Lai Jiangshan <jiangshan.ljs@...group.com>

Parents added into the struct kvm_mmu_pages are never used.

Signed-off-by: Lai Jiangshan <jiangshan.ljs@...group.com>
---
 arch/x86/kvm/mmu/mmu.c | 36 +++++-------------------------------
 1 file changed, 5 insertions(+), 31 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index a5563e5ee2e5..304a515bd073 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -1751,10 +1751,9 @@ static int mmu_pages_add(struct kvm_mmu_pages *pvec, struct kvm_mmu_page *sp)
 {
 	int i;
 
-	if (sp->unsync)
-		for (i=0; i < pvec->nr; i++)
-			if (pvec->sp[i] == sp)
-				return 0;
+	for (i=0; i < pvec->nr; i++)
+		if (pvec->sp[i] == sp)
+			return 0;
 
 	pvec->sp[pvec->nr] = sp;
 	pvec->nr++;
@@ -1785,9 +1784,6 @@ static int __mmu_unsync_walk_and_clear(struct kvm_mmu_page *sp,
 		child = to_shadow_page(ent & PT64_BASE_ADDR_MASK);
 
 		if (child->unsync_children) {
-			if (mmu_pages_add(pvec, child))
-				return -ENOSPC;
-
 			ret = __mmu_unsync_walk_and_clear(child, pvec);
 			if (ret < 0)
 				return ret;
@@ -1818,7 +1814,6 @@ static int mmu_unsync_walk_and_clear(struct kvm_mmu_page *sp,
 	if (!sp->unsync_children)
 		return 0;
 
-	mmu_pages_add(pvec, sp);
 	return __mmu_unsync_walk_and_clear(sp, pvec);
 }
 
@@ -1897,33 +1892,12 @@ static bool is_obsolete_sp(struct kvm *kvm, struct kvm_mmu_page *sp)
 
 static int mmu_pages_next(struct kvm_mmu_pages *pvec, int i)
 {
-	int n;
-
-	for (n = i+1; n < pvec->nr; n++) {
-		struct kvm_mmu_page *sp = pvec->sp[n];
-		int level = sp->role.level;
-
-		if (level == PG_LEVEL_4K)
-			break;
-
-	}
-
-	return n;
+	return i + 1;
 }
 
 static int mmu_pages_first(struct kvm_mmu_pages *pvec)
 {
-	struct kvm_mmu_page *sp;
-	int level;
-
-	if (pvec->nr == 0)
-		return 0;
-
-	sp = pvec->sp[0];
-	level = sp->role.level;
-	WARN_ON(level == PG_LEVEL_4K);
-
-	return mmu_pages_next(pvec, 0);
+	return 0;
 }
 
 static int mmu_sync_children(struct kvm_vcpu *vcpu,
-- 
2.19.1.6.gb485710b