linux-kernel - [RFC PATCH 39/67] KVM: x86/mmu: Refactor shadow walk in __direct

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Date:   Mon, 16 Nov 2020 10:26:24 -0800
From:   isaku.yamahata@...el.com
To:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H . Peter Anvin" <hpa@...or.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, x86@...nel.org,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     isaku.yamahata@...el.com, isaku.yamahata@...il.com,
        Sean Christopherson <sean.j.christopherson@...el.com>
Subject: [RFC PATCH 39/67] KVM: x86/mmu: Refactor shadow walk in __direct_map() to reduce indentation

From: Sean Christopherson <sean.j.christopherson@...el.com>

Employ a 'continue' to reduce the indentation for linking a new shadow
page during __direct_map() in preparation for linking private pages.

Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
---
 arch/x86/kvm/mmu/mmu.c | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 732510ecda36..25aafac9b5de 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -2953,16 +2953,15 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code,
 			break;
 
 		drop_large_spte(vcpu, it.sptep);
-		if (!is_shadow_present_pte(*it.sptep)) {
-			sp = __kvm_mmu_get_page(vcpu, base_gfn,
-						gfn_stolen_bits, it.addr,
-						it.level - 1, true, ACC_ALL);
-
-			link_shadow_page(vcpu, it.sptep, sp);
-			if (is_tdp && huge_page_disallowed &&
-			    req_level >= it.level)
-				account_huge_nx_page(vcpu->kvm, sp);
-		}
+		if (is_shadow_present_pte(*it.sptep))
+			continue;
+
+		sp = __kvm_mmu_get_page(vcpu, base_gfn, gfn_stolen_bits,
+					it.addr, it.level - 1, true, ACC_ALL);
+
+		link_shadow_page(vcpu, it.sptep, sp);
+		if (is_tdp && huge_page_disallowed && req_level >= it.level)
+			account_huge_nx_page(vcpu->kvm, sp);
 	}
 
 	ret = mmu_set_spte(vcpu, it.sptep, ACC_ALL,
-- 
2.17.1