linux-kernel - [PATCH 09/11] KVM: MMU: simplify mmu_need_write

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Date:	Tue,  1 Dec 2015 02:26:11 +0800
From:	Xiao Guangrong <guangrong.xiao@...ux.intel.com>
To:	pbonzini@...hat.com
Cc:	gleb@...nel.org, mtosatti@...hat.com, kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Xiao Guangrong <guangrong.xiao@...ux.intel.com>
Subject: [PATCH 09/11] KVM: MMU: simplify mmu_need_write_protect

Now, all non-leaf shadow page are page tracked, if gfn is not tracked
there is no non-leaf shadow page of gfn is existed, we can directly
make the shadow page of gfn to unsync

Signed-off-by: Xiao Guangrong <guangrong.xiao@...ux.intel.com>
---
 arch/x86/kvm/mmu.c | 26 ++++++++------------------
 1 file changed, 8 insertions(+), 18 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 5a2ca73..f89e77f 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2461,41 +2461,31 @@ static void __kvm_unsync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
 	kvm_mmu_mark_parents_unsync(sp);
 }
 
-static void kvm_unsync_pages(struct kvm_vcpu *vcpu,  gfn_t gfn)
+static bool kvm_unsync_pages(struct kvm_vcpu *vcpu, gfn_t gfn,
+			     bool can_unsync)
 {
 	struct kvm_mmu_page *s;
 
 	for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn) {
+		if (!can_unsync)
+			return true;
+
 		if (s->unsync)
 			continue;
 		WARN_ON(s->role.level != PT_PAGE_TABLE_LEVEL);
 		__kvm_unsync_page(vcpu, s);
 	}
+
+	return false;
 }
 
 static bool mmu_need_write_protect(struct kvm_vcpu *vcpu, gfn_t gfn,
 				   bool can_unsync)
 {
-	struct kvm_mmu_page *s;
-	bool need_unsync = false;
-
 	if (kvm_page_track_check_mode(vcpu, gfn, KVM_PAGE_TRACK_WRITE))
 		return true;
 
-	for_each_gfn_indirect_valid_sp(vcpu->kvm, s, gfn) {
-		if (!can_unsync)
-			return true;
-
-		if (s->role.level != PT_PAGE_TABLE_LEVEL)
-			return true;
-
-		if (!s->unsync)
-			need_unsync = true;
-	}
-	if (need_unsync)
-		kvm_unsync_pages(vcpu, gfn);
-
-	return false;
+	return kvm_unsync_pages(vcpu, gfn, can_unsync);
 }
 
 static bool kvm_is_mmio_pfn(pfn_t pfn)
-- 
1.8.3.1

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