linux-kernel - [PATCH v2 09/45] KVM: x86: Move allocation of pio

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Message-Id: <20191218215530.2280-10-sean.j.christopherson@intel.com>
Date:   Wed, 18 Dec 2019 13:54:54 -0800
From:   Sean Christopherson <sean.j.christopherson@...el.com>
To:     Marc Zyngier <maz@...nel.org>, James Hogan <jhogan@...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>,
        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-ppc@...r.kernel.org,
        kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Greg Kurz <groug@...d.org>
Subject: [PATCH v2 09/45] KVM: x86: Move allocation of pio_data page down a few lines

Allocate the pio_data page after creating the MMU and local APIC so that
all direct memory allocations are grouped together.  This allows setting
the return value to -ENOMEM prior to starting the allocations instead of
setting it in the fail path for every allocation.

The pio_data page is only consumed when KVM_RUN is invoked, i.e. moving
its allocation has no real functional impact.

Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
---
 arch/x86/kvm/x86.c | 33 +++++++++++++--------------------
 1 file changed, 13 insertions(+), 20 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e3f122dca5f8..b3e367963b08 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9420,18 +9420,11 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
 	else
 		vcpu->arch.mp_state = KVM_MP_STATE_UNINITIALIZED;
 
-	page = alloc_page(GFP_KERNEL | __GFP_ZERO);
-	if (!page) {
-		r = -ENOMEM;
-		goto fail;
-	}
-	vcpu->arch.pio_data = page_address(page);
-
 	kvm_set_tsc_khz(vcpu, max_tsc_khz);
 
 	r = kvm_mmu_create(vcpu);
 	if (r < 0)
-		goto fail_free_pio_data;
+		return r;
 
 	if (irqchip_in_kernel(vcpu->kvm)) {
 		vcpu->arch.apicv_active = kvm_x86_ops->get_enable_apicv(vcpu->kvm);
@@ -9441,25 +9434,27 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
 	} else
 		static_key_slow_inc(&kvm_no_apic_vcpu);
 
+	r = -ENOMEM;
+
+	page = alloc_page(GFP_KERNEL | __GFP_ZERO);
+	if (!page)
+		goto fail_free_lapic;
+	vcpu->arch.pio_data = page_address(page);
+
 	vcpu->arch.mce_banks = kzalloc(KVM_MAX_MCE_BANKS * sizeof(u64) * 4,
 				       GFP_KERNEL_ACCOUNT);
-	if (!vcpu->arch.mce_banks) {
-		r = -ENOMEM;
-		goto fail_free_lapic;
-	}
+	if (!vcpu->arch.mce_banks)
+		goto fail_free_pio_data;
 	vcpu->arch.mcg_cap = KVM_MAX_MCE_BANKS;
 
 	if (!zalloc_cpumask_var(&vcpu->arch.wbinvd_dirty_mask,
-				GFP_KERNEL_ACCOUNT)) {
-		r = -ENOMEM;
+				GFP_KERNEL_ACCOUNT))
 		goto fail_free_mce_banks;
-	}
 
 	vcpu->arch.user_fpu = kmem_cache_zalloc(x86_fpu_cache,
 						GFP_KERNEL_ACCOUNT);
 	if (!vcpu->arch.user_fpu) {
 		pr_err("kvm: failed to allocate userspace's fpu\n");
-		r = -ENOMEM;
 		goto free_wbinvd_dirty_mask;
 	}
 
@@ -9467,7 +9462,6 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
 						 GFP_KERNEL_ACCOUNT);
 	if (!vcpu->arch.guest_fpu) {
 		pr_err("kvm: failed to allocate vcpu's fpu\n");
-		r = -ENOMEM;
 		goto free_user_fpu;
 	}
 	fx_init(vcpu);
@@ -9494,13 +9488,12 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
 	free_cpumask_var(vcpu->arch.wbinvd_dirty_mask);
 fail_free_mce_banks:
 	kfree(vcpu->arch.mce_banks);
+fail_free_pio_data:
+	free_page((unsigned long)vcpu->arch.pio_data);
 fail_free_lapic:
 	kvm_free_lapic(vcpu);
 fail_mmu_destroy:
 	kvm_mmu_destroy(vcpu);
-fail_free_pio_data:
-	free_page((unsigned long)vcpu->arch.pio_data);
-fail:
 	return r;
 }
 
-- 
2.24.1