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Date:   Mon, 5 Jun 2023 22:42:59 +0200
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Subject: Re: [PATCH v2] KVM: allow KVM_BUG/KVM_BUG_ON to handle 64-bit cond
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To:     Sean Christopherson <seanjc@google.com>
Cc:     dmatlack@google.com, mizhang@google.com, isaku.yamahata@gmail.com,
        pbonzini@redhat.com, Wei Wang <wei.w.wang@intel.com>,
        kvm@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20230307135233.54684-1-wei.w.wang@intel.com>
 <168565180722.660019.15543226381784798973.b4-ty@google.com>
 <8f319a1e-a869-b666-b606-c0b4764ef7b1@rbox.co> <ZHofVKJxjaUxIDUN@google.com>
 <7a4a503d-9fc4-d366-02b4-bc145943bd45@rbox.co> <ZH39H0gpNX4ak6yM@google.com>
From:   Michal Luczaj <mhal@rbox.co>
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On 6/5/23 17:19, Sean Christopherson wrote:
> On Mon, Jun 05, 2023, Michal Luczaj wrote:
>> OK, so xa_store() aside[*], I see some bool-to-bools:
>>
>> arch/x86/kvm/x86.c:
>> 	kvm_msr_allowed():allowed = !!test_bit(index - start, bitmap);
>> arch/x86/kvm/hyperv.c:
>> 	kvm_hv_hypercall():hc.rep = !!(hc.rep_cnt || hc.rep_idx);
>> arch/x86/kvm/mmu/mmu.c:
>> 	update_pkru_bitmask():
>> 		pkey_bits = !!check_pkey;
>> 		pkey_bits |= (!!check_write) << 1;
>> arch/x86/kvm/svm/svm.c:
>> 	msr_write_intercepted():return !!test_bit(bit_write,  &tmp);
>> 	svm_vcpu_after_set_cpuid():
>> 		2x set_msr_interception...
>> tools/testing/selftests/kvm/x86_64/vmx_exception_with_invalid_guest_state.c:
>> 	set_or_clear_invalid_guest_state():sregs.tr.unusable = !!set;
>>
>> But perhaps this is a matter of style and those were meant to be this kind-of
>> explicit?
> 
> I doubt it, I'm guessing most cases are due to the author being overzealous for
> one reason or another, e.g. I suspect the test_bit() ones are due to the original
> author incorrectly assuming test_bit() returned an unsigned long, i.e. the bit,
> as opposed to the bool.
> 
> If you want to clean these up, I'd say "fix" the test_bit() cases, but leave the
> others alone.  The test_bit() ones are clearly redundant, and IMO can be actively
> due to implying test_bit() returns something other than a bool.

Done: https://lore.kernel.org/kvm/20230605200158.118109-1-mhal@rbox.co/