KVM: x86: fix CPUID entries returned by KVM_GET_CPUID2 ioctl

Recent commit 255cbec modified struct kvm_vcpu_arch to make
'cpuid_entries' a pointer to an array of kvm_cpuid_entry2 entries
rather than embedding the array in the struct. KVM_SET_CPUID and
KVM_SET_CPUID2 were updated accordingly, but KVM_GET_CPUID2 was missed.

As a result, KVM_GET_CPUID2 currently returns random fields from struct
kvm_vcpu_arch to userspace rather than the expected CPUID values. Fix
this by treating 'cpuid_entries' as a pointer when copying its
contents to userspace buffer.

Fixes: 255cbec ("KVM: x86: allocate vcpu->arch.cpuid_entries dynamically")
Cc: Vitaly Kuznetsov <[email protected]>
Signed-off-by: Michael Roth <[email protected]>
Message-Id: <[email protected]>
Cc: [email protected]
Signed-off-by: Paolo Bonzini <[email protected]>

Author: mdroth

arch/x86/kvm/cpuid.c

@@ -321,7 +321,7 @@ int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu,
 	if (cpuid->nent < vcpu->arch.cpuid_nent)
 		goto out;
 	r = -EFAULT;
-	if (copy_to_user(entries, &vcpu->arch.cpuid_entries,
+	if (copy_to_user(entries, vcpu->arch.cpuid_entries,
 			 vcpu->arch.cpuid_nent * sizeof(struct kvm_cpuid_entry2)))
 		goto out;
 	return 0;