From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
When kvm_vcpu_ioctl_get_cpuid2() fails, we set cpuid->nent to the value of
vcpu->arch.cpuid_nent. But this is in vain as cpuid->nent is not copied to
userspace by copy_to_user() from call site. Get rid of this meaningless
assignment and further cleanup the var r and out jump label.
On the other hand, when kvm_vcpu_ioctl_get_cpuid2() succeeds, we do not
change the content of struct cpuid. We can avoid copy_to_user() from call
site as struct cpuid remain unchanged.
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
---
arch/x86/kvm/cpuid.c | 14 ++++----------
arch/x86/kvm/x86.c | 6 ------
2 files changed, 4 insertions(+), 16 deletions(-)
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index b1c469446b07..b83cedc63328 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -265,20 +265,14 @@ int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu,
struct kvm_cpuid2 *cpuid,
struct kvm_cpuid_entry2 __user *entries)
{
- int r;
-
- r = -E2BIG;
if (cpuid->nent < vcpu->arch.cpuid_nent)
- goto out;
- r = -EFAULT;
+ return -E2BIG;
+
if (copy_to_user(entries, &vcpu->arch.cpuid_entries,
vcpu->arch.cpuid_nent * sizeof(struct kvm_cpuid_entry2)))
- goto out;
- return 0;
+ return -EFAULT;
-out:
- cpuid->nent = vcpu->arch.cpuid_nent;
- return r;
+ return 0;
}
static __always_inline void cpuid_mask(u32 *word, int wordnum)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index fbabb2f06273..683c54e7be36 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4295,12 +4295,6 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
goto out;
r = kvm_vcpu_ioctl_get_cpuid2(vcpu, &cpuid,
cpuid_arg->entries);
- if (r)
- goto out;
- r = -EFAULT;
- if (copy_to_user(cpuid_arg, &cpuid, sizeof(cpuid)))
- goto out;
- r = 0;
break;
}
case KVM_GET_MSRS: {
--
2.19.1
