KVM: Use memdup_user instead of kmalloc/copy_from_user

Switch to using memdup_user when possible. This makes code more
smaller and compact, and prevents errors.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 12 insertions, 17 deletions

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index a6e612fced73..d8bac0751666 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1821,12 +1821,11 @@ out_free1:
                 struct kvm_regs *kvm_regs;
 
                 r = -ENOMEM;
-                kvm_regs = kzalloc(sizeof(struct kvm_regs), GFP_KERNEL);
-                if (!kvm_regs)
+                kvm_regs = memdup_user(argp, sizeof(*kvm_regs));
+                if (IS_ERR(kvm_regs)) {
+                        r = PTR_ERR(kvm_regs);
                         goto out;
-                r = -EFAULT;
-                if (copy_from_user(kvm_regs, argp, sizeof(struct kvm_regs)))
-                        goto out_free2;
+                }
                 r = kvm_arch_vcpu_ioctl_set_regs(vcpu, kvm_regs);
                 if (r)
                         goto out_free2;
@@ -1850,13 +1849,11 @@ out_free2:
                 break;
         }
         case KVM_SET_SREGS: {
-                kvm_sregs = kmalloc(sizeof(struct kvm_sregs), GFP_KERNEL);
-                r = -ENOMEM;
-                if (!kvm_sregs)
-                        goto out;
-                r = -EFAULT;
-                if (copy_from_user(kvm_sregs, argp, sizeof(struct kvm_sregs)))
+                kvm_sregs = memdup_user(argp, sizeof(*kvm_sregs));
+                if (IS_ERR(kvm_sregs)) {
+                        r = PTR_ERR(kvm_sregs);
                         goto out;
+                }
                 r = kvm_arch_vcpu_ioctl_set_sregs(vcpu, kvm_sregs);
                 if (r)
                         goto out;
@@ -1952,13 +1949,11 @@ out_free2:
                 break;
         }
         case KVM_SET_FPU: {
-                fpu = kmalloc(sizeof(struct kvm_fpu), GFP_KERNEL);
-                r = -ENOMEM;
-                if (!fpu)
-                        goto out;
-                r = -EFAULT;
-                if (copy_from_user(fpu, argp, sizeof(struct kvm_fpu)))
+                fpu = memdup_user(argp, sizeof(*fpu));
+                if (IS_ERR(fpu)) {
+                        r = PTR_ERR(fpu);
                         goto out;
+                }
                 r = kvm_arch_vcpu_ioctl_set_fpu(vcpu, fpu);
                 if (r)
                         goto out;