linux-kernel - [PATCH v2 4/5] KVM: MMU: introduce page_fault_start and page_fault

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Date:	Fri, 14 Sep 2012 17:59:06 +0800
From:	Xiao Guangrong <xiaoguangrong@...ux.vnet.ibm.com>
To:	Xiao Guangrong <xiaoguangrong@...ux.vnet.ibm.com>
CC:	Avi Kivity <avi@...hat.com>, Marcelo Tosatti <mtosatti@...hat.com>,
	LKML <linux-kernel@...r.kernel.org>, KVM <kvm@...r.kernel.org>
Subject: [PATCH v2 4/5] KVM: MMU: introduce page_fault_start and page_fault_end

Wrap the common operations into these two functions

Signed-off-by: Xiao Guangrong <xiaoguangrong@...ux.vnet.ibm.com>
---
 arch/x86/kvm/mmu.c         |   53 +++++++++++++++++++++++++++----------------
 arch/x86/kvm/paging_tmpl.h |   16 +++++--------
 2 files changed, 39 insertions(+), 30 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 29ce28b..7e7b8cd 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2825,6 +2825,29 @@ exit:
 static bool try_async_pf(struct kvm_vcpu *vcpu, bool prefault, gfn_t gfn,
 			 gva_t gva, pfn_t *pfn, bool write, bool *writable);

+static bool
+page_fault_start(struct kvm_vcpu *vcpu, gfn_t *gfnp, pfn_t *pfnp, int *levelp,
+		 bool force_pt_level, unsigned long mmu_seq)
+{
+	spin_lock(&vcpu->kvm->mmu_lock);
+	if (mmu_notifier_retry(vcpu, mmu_seq))
+		return false;
+
+	kvm_mmu_free_some_pages(vcpu);
+	if (likely(!force_pt_level))
+		transparent_hugepage_adjust(vcpu, gfnp, pfnp, levelp);
+
+	return true;
+}
+
+static void page_fault_end(struct kvm_vcpu *vcpu, pfn_t pfn)
+{
+	spin_unlock(&vcpu->kvm->mmu_lock);
+
+	if (!is_error_pfn(pfn))
+		kvm_release_pfn_clean(pfn);
+}
+
 static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, u32 error_code,
 			 gfn_t gfn, bool prefault)
 {
@@ -2862,22 +2885,17 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, u32 error_code,
 	if (handle_abnormal_pfn(vcpu, v, gfn, pfn, ACC_ALL, &r))
 		return r;

-	spin_lock(&vcpu->kvm->mmu_lock);
-	if (mmu_notifier_retry(vcpu, mmu_seq)) {
+	if (!page_fault_start(vcpu, &gfn, &pfn, &level, force_pt_level,
+	      mmu_seq)) {
 		r = 0;
-		goto out_unlock;
+		goto exit;
 	}

-	kvm_mmu_free_some_pages(vcpu);
-	if (likely(!force_pt_level))
-		transparent_hugepage_adjust(vcpu, &gfn, &pfn, &level);
 	r = __direct_map(vcpu, v, write, map_writable, level, gfn, pfn,
 			 prefault);

-out_unlock:
-	spin_unlock(&vcpu->kvm->mmu_lock);
-	if (!is_error_pfn(pfn))
-		kvm_release_pfn_clean(pfn);
+exit:
+	page_fault_end(vcpu, pfn);
 	return r;
 }

@@ -3331,22 +3349,17 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code,
 	if (handle_abnormal_pfn(vcpu, 0, gfn, pfn, ACC_ALL, &r))
 		return r;

-	spin_lock(&vcpu->kvm->mmu_lock);
-	if (mmu_notifier_retry(vcpu, mmu_seq)) {
+	if (!page_fault_start(vcpu, &gfn, &pfn, &level, force_pt_level,
+	      mmu_seq)) {
 		r = 0;
-		goto out_unlock;
+		goto exit;
 	}

-	kvm_mmu_free_some_pages(vcpu);
-	if (likely(!force_pt_level))
-		transparent_hugepage_adjust(vcpu, &gfn, &pfn, &level);
 	r = __direct_map(vcpu, gpa, write, map_writable,
 			 level, gfn, pfn, prefault);

-out_unlock:
-	spin_unlock(&vcpu->kvm->mmu_lock);
-	if (!is_error_pfn(pfn))
-		kvm_release_pfn_clean(pfn);
+exit:
+	page_fault_end(vcpu, pfn);
 	return r;
 }

diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 0adf376..1a738c5 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -624,26 +624,22 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code,
 				walker.gfn, pfn, walker.pte_access, &r))
 		return r;

-	spin_lock(&vcpu->kvm->mmu_lock);
-	if (mmu_notifier_retry(vcpu, mmu_seq)) {
+	if (!page_fault_start(vcpu, &walker.gfn, &pfn, &level,
+	      force_pt_level, mmu_seq)) {
 		r = 0;
-		goto out_unlock;
+		goto exit;
 	}

 	kvm_mmu_audit(vcpu, AUDIT_PRE_PAGE_FAULT);
-	kvm_mmu_free_some_pages(vcpu);
-	if (!force_pt_level)
-		transparent_hugepage_adjust(vcpu, &walker.gfn, &pfn, &level);
+
 	r = FNAME(fetch)(vcpu, addr, &walker, user_fault, write_fault,
 			 level, pfn, map_writable, prefault);

 	++vcpu->stat.pf_fixed;
 	kvm_mmu_audit(vcpu, AUDIT_POST_PAGE_FAULT);

-out_unlock:
-	spin_unlock(&vcpu->kvm->mmu_lock);
-	if (!is_error_pfn(pfn))
-		kvm_release_pfn_clean(pfn);
+exit:
+	page_fault_end(vcpu, pfn);
 	return r;
 }

-- 
1.7.7.6

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