[PATCH 09/45] KVM: x86: Move allocation of pio_data page down a few lines

Sean Christopherson
2019-10-22T01:58:49Z

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@intel.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 777a29b3c38b..b33ca472ff4f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9338,18 +9338,11 @@ 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);
@@ -9359,25 +9352,27 @@ 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;
}

@@ -9385,7 +9380,6 @@ 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);
@@ -9412,13 +9406,12 @@ 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;
}

--
2.22.0