linux-kernel - [PATCH 09/21] KVM: x86/mmu: Separate the memory caches for shadow pages and gfn arrays

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Date:   Fri,  5 Jun 2020 14:38:41 -0700
From:   Sean Christopherson <sean.j.christopherson@...el.com>
To:     Marc Zyngier <maz@...nel.org>, Paul Mackerras <paulus@...abs.org>,
        Christian Borntraeger <borntraeger@...ibm.com>,
        Janosch Frank <frankja@...ux.ibm.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     James Morse <james.morse@....com>,
        Julien Thierry <julien.thierry.kdev@...il.com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        David Hildenbrand <david@...hat.com>,
        Cornelia Huck <cohuck@...hat.com>,
        Claudio Imbrenda <imbrenda@...ux.ibm.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu,
        linux-mips@...r.kernel.org, kvm@...r.kernel.org,
        kvm-ppc@...r.kernel.org, linux-kernel@...r.kernel.org,
        Peter Feiner <pfeiner@...gle.com>,
        Peter Shier <pshier@...gle.com>,
        Junaid Shahid <junaids@...gle.com>,
        Ben Gardon <bgardon@...gle.com>,
        Christoffer Dall <christoffer.dall@....com>
Subject: [PATCH 09/21] KVM: x86/mmu: Separate the memory caches for shadow pages and gfn arrays

Use separate caches for allocating shadow pages versus gfn arrays.  This
sets the stage for specifying __GFP_ZERO when allocating shadow pages
without incurring extra cost for gfn arrays.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
---
 arch/x86/include/asm/kvm_host.h |  3 ++-
 arch/x86/kvm/mmu/mmu.c          | 15 ++++++++++-----
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 16347b050754..e7a427547557 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -636,7 +636,8 @@ struct kvm_vcpu_arch {
 	struct kvm_mmu *walk_mmu;
 
 	struct kvm_mmu_memory_cache mmu_pte_list_desc_cache;
-	struct kvm_mmu_memory_cache mmu_page_cache;
+	struct kvm_mmu_memory_cache mmu_shadow_page_cache;
+	struct kvm_mmu_memory_cache mmu_gfn_array_cache;
 	struct kvm_mmu_memory_cache mmu_page_header_cache;
 
 	/*
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 451e0365e5dd..d245acece3cd 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -1108,8 +1108,12 @@ static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
 				   1 + PT64_ROOT_MAX_LEVEL + PTE_PREFETCH_NUM);
 	if (r)
 		return r;
-	r = mmu_topup_memory_cache(&vcpu->arch.mmu_page_cache,
-				   2 * PT64_ROOT_MAX_LEVEL);
+	r = mmu_topup_memory_cache(&vcpu->arch.mmu_shadow_page_cache,
+				   PT64_ROOT_MAX_LEVEL);
+	if (r)
+		return r;
+	r = mmu_topup_memory_cache(&vcpu->arch.mmu_gfn_array_cache,
+				   PT64_ROOT_MAX_LEVEL);
 	if (r)
 		return r;
 	return mmu_topup_memory_cache(&vcpu->arch.mmu_page_header_cache,
@@ -1119,7 +1123,8 @@ static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
 static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
 {
 	mmu_free_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache);
-	mmu_free_memory_cache(&vcpu->arch.mmu_page_cache);
+	mmu_free_memory_cache(&vcpu->arch.mmu_shadow_page_cache);
+	mmu_free_memory_cache(&vcpu->arch.mmu_gfn_array_cache);
 	mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache);
 }
 
@@ -2096,9 +2101,9 @@ static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, int direct
 	struct kvm_mmu_page *sp;
 
 	sp = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache);
-	sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache);
+	sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_shadow_page_cache);
 	if (!direct)
-		sp->gfns = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache);
+		sp->gfns = mmu_memory_cache_alloc(&vcpu->arch.mmu_gfn_array_cache);
 	set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
 
 	/*
-- 
2.26.0