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KVM: nSVM: Replace kzalloc() + copy_from_user() with memdup_user()

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Replace kzalloc() followed by copy_from_user() with memdup_user() to
improve and simplify svm_set_nested_state().

Return early if an error occurs instead of trying to allocate memory for
'save' when memory allocation for 'ctl' already failed.

Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Link: https://lore.kernel.org/r/20250903002951.118912-1-thorsten.blum@linux.dev
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Thorsten Blum
2025-09-03 02:29:50 +02:00
committed by Sean Christopherson
parent 2f5f8fb9de
commit fc55b4cda0
1 changed files with 8 additions and 10 deletions
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arch/x86/kvm/svm/nested.c
+8 -10
View File
@@ -1798,17 +1798,15 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
if (kvm_state->size < sizeof(*kvm_state) + KVM_STATE_NESTED_SVM_VMCB_SIZE)
return -EINVAL;
ret = -ENOMEM;
ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
save = kzalloc(sizeof(*save), GFP_KERNEL);
if (!ctl || !save)
goto out_free;
ctl = memdup_user(&user_vmcb->control, sizeof(*ctl));
if (IS_ERR(ctl))
return PTR_ERR(ctl);
ret = -EFAULT;
if (copy_from_user(ctl, &user_vmcb->control, sizeof(*ctl)))
goto out_free;
if (copy_from_user(save, &user_vmcb->save, sizeof(*save)))
goto out_free;
save = memdup_user(&user_vmcb->save, sizeof(*save));
if (IS_ERR(save)) {
kfree(ctl);
return PTR_ERR(save);
}
ret = -EINVAL;
__nested_copy_vmcb_control_to_cache(vcpu, &ctl_cached, ctl);