[PATCH v7 3/9] kvm: Make init_rmode_identity_map() return 0 on success.

From: Tang Chen
Date: Sat Sep 20 2014 - 06:48:37 EST


In init_rmode_identity_map(), there two variables indicating the return
value, r and ret, and it return 0 on error, 1 on success. The function
is only called by vmx_create_vcpu(), and r is redundant.

This patch removes the redundant variable r, and make init_rmode_identity_map()
return 0 on success, -errno on failure.

Signed-off-by: Tang Chen <tangchen@xxxxxxxxxxxxxx>
---
arch/x86/kvm/vmx.c | 31 +++++++++++++++----------------
1 file changed, 15 insertions(+), 16 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 4fb84ad..72a0470 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3939,45 +3939,42 @@ out:

static int init_rmode_identity_map(struct kvm *kvm)
{
- int i, idx, r, ret = 0;
+ int i, idx, ret = 0;
pfn_t identity_map_pfn;
u32 tmp;

if (!enable_ept)
- return 1;
+ return 0;

/* Protect kvm->arch.ept_identity_pagetable_done. */
mutex_lock(&kvm->slots_lock);

- if (likely(kvm->arch.ept_identity_pagetable_done)) {
- ret = 1;
+ if (likely(kvm->arch.ept_identity_pagetable_done))
goto out2;
- }

identity_map_pfn = kvm->arch.ept_identity_map_addr >> PAGE_SHIFT;

- r = alloc_identity_pagetable(kvm);
- if (r)
+ ret = alloc_identity_pagetable(kvm);
+ if (ret)
goto out2;

idx = srcu_read_lock(&kvm->srcu);
- r = kvm_clear_guest_page(kvm, identity_map_pfn, 0, PAGE_SIZE);
- if (r < 0)
+ ret = kvm_clear_guest_page(kvm, identity_map_pfn, 0, PAGE_SIZE);
+ if (ret)
goto out;
/* Set up identity-mapping pagetable for EPT in real mode */
for (i = 0; i < PT32_ENT_PER_PAGE; i++) {
tmp = (i << 22) + (_PAGE_PRESENT | _PAGE_RW | _PAGE_USER |
_PAGE_ACCESSED | _PAGE_DIRTY | _PAGE_PSE);
- r = kvm_write_guest_page(kvm, identity_map_pfn,
+ ret = kvm_write_guest_page(kvm, identity_map_pfn,
&tmp, i * sizeof(tmp), sizeof(tmp));
- if (r < 0)
+ if (ret)
goto out;
}
kvm->arch.ept_identity_pagetable_done = true;
- ret = 1;
+
out:
srcu_read_unlock(&kvm->srcu, idx);
-
out2:
mutex_unlock(&kvm->slots_lock);
return ret;
@@ -7604,11 +7601,13 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id)
if (err)
goto free_vcpu;

+ /* Set err to -ENOMEM to handle memory allocation error. */
+ err = -ENOMEM;
+
vmx->guest_msrs = kmalloc(PAGE_SIZE, GFP_KERNEL);
BUILD_BUG_ON(ARRAY_SIZE(vmx_msr_index) * sizeof(vmx->guest_msrs[0])
> PAGE_SIZE);

- err = -ENOMEM;
if (!vmx->guest_msrs) {
goto uninit_vcpu;
}
@@ -7641,8 +7640,8 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id)
if (!kvm->arch.ept_identity_map_addr)
kvm->arch.ept_identity_map_addr =
VMX_EPT_IDENTITY_PAGETABLE_ADDR;
- err = -ENOMEM;
- if (!init_rmode_identity_map(kvm))
+ err = init_rmode_identity_map(kvm);
+ if (err < 0)
goto free_vmcs;
}

--
1.8.3.1

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