Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Wed, 21 Dec 2022 22:24:13 +0000
In-Reply-To: <20221221222418.3307832-1-bgardon@google.com>
Mime-Version: 1.0
References: <20221221222418.3307832-1-bgardon@google.com>
Message-ID: <20221221222418.3307832-10-bgardon@google.com>
Subject: [RFC 09/14] KVM: x86/MMU: Only make pages available on Shadow MMU fault
From:   Ben Gardon <bgardon@google.com>
To:     linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc:     Paolo Bonzini <pbonzini@redhat.com>, Peter Xu <peterx@redhat.com>,
        Sean Christopherson <seanjc@google.com>,
        David Matlack <dmatlack@google.com>,
        Vipin Sharma <vipinsh@google.com>,
        Nagareddy Reddy <nspreddy@google.com>,
        Ben Gardon <bgardon@google.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Now that the Shadow MMU has been factored out of mmu.c and the naming
sheme has been cleaned up, it's clear that there's an unnecessary
operation in direct_page_fault(). Since the MMU page quota is only
applied to the Shadow MMU, there's no point to calling
kvm_shadow_mmu_make_pages_available on a fault where the TDP MMU is
going to handle installing new TDP PTEs.

Signed-off-by: Ben Gardon <bgardon@google.com>
---
 arch/x86/kvm/mmu/mmu.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index bacb519ba7b4..568b36de9eeb 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -1469,14 +1469,14 @@ static int direct_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
 	if (is_page_fault_stale(vcpu, fault, mmu_seq))
 		goto out_unlock;
 
-	r = kvm_shadow_mmu_make_pages_available(vcpu);
-	if (r)
-		goto out_unlock;
-
 	if (is_tdp_mmu_fault)
 		r = kvm_tdp_mmu_map(vcpu, fault);
-	else
+	else {
+		r = kvm_shadow_mmu_make_pages_available(vcpu);
+		if (r)
+			goto out_unlock;
 		r = kvm_shadow_mmu_direct_map(vcpu, fault);
+	}
 
 out_unlock:
 	if (is_tdp_mmu_fault)
-- 
2.39.0.314.g84b9a713c41-goog