From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxim Levitsky Date: Thu, 28 Oct 2021 06:05:35 +0000 Subject: Re: [PATCH v2 23/43] KVM: VMX: Use boolean returns for Posted Interrupt "test" helpers Message-Id: <49c6c208841a85dbcb397acdc7f20b81402e71fb.camel@redhat.com> List-Id: References: <20211009021236.4122790-1-seanjc@google.com> <20211009021236.4122790-24-seanjc@google.com> In-Reply-To: <20211009021236.4122790-24-seanjc@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Sean Christopherson , Marc Zyngier , Huacai Chen , Aleksandar Markovic , Paul Mackerras , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Christian Borntraeger , Janosch Frank , Paolo Bonzini Cc: James Morse , Alexandru Elisei , Suzuki K Poulose , Atish Patra , David Hildenbrand , Cornelia Huck , Claudio Imbrenda , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-mips@vger.kernel.org, kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, David Matlack , Oliver Upton , Jing Zhang On Fri, 2021-10-08 at 19:12 -0700, Sean Christopherson wrote: > Return bools instead of ints for the posted interrupt "test" helpers. > The bit position of the flag being test does not matter to the callers, > and is in fact lost by virtue of test_bit() itself returning a bool. > > Returning ints is potentially dangerous, e.g. "pi_test_on(pi_desc) = 1" > is safe-ish because ON is bit 0 and thus any sane implementation of > pi_test_on() will work, but for SN (bit 1), checking "= 1" would rely on > pi_test_on() to return 0 or 1, a.k.a. bools, as opposed to 0 or 2 (the > positive bit position). > > Signed-off-by: Sean Christopherson > --- > arch/x86/kvm/vmx/posted_intr.c | 4 ++-- > arch/x86/kvm/vmx/posted_intr.h | 6 +++--- > 2 files changed, 5 insertions(+), 5 deletions(-) > > diff --git a/arch/x86/kvm/vmx/posted_intr.c b/arch/x86/kvm/vmx/posted_intr.c > index 6c2110d91b06..1688f8dc535a 100644 > --- a/arch/x86/kvm/vmx/posted_intr.c > +++ b/arch/x86/kvm/vmx/posted_intr.c > @@ -185,7 +185,7 @@ int pi_pre_block(struct kvm_vcpu *vcpu) > new.control) != old.control); > > /* We should not block the vCPU if an interrupt is posted for it. */ > - if (pi_test_on(pi_desc) = 1) > + if (pi_test_on(pi_desc)) > __pi_post_block(vcpu); > > local_irq_enable(); > @@ -216,7 +216,7 @@ void pi_wakeup_handler(void) > blocked_vcpu_list) { > struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu); > > - if (pi_test_on(pi_desc) = 1) > + if (pi_test_on(pi_desc)) > kvm_vcpu_kick(vcpu); > } > spin_unlock(&per_cpu(blocked_vcpu_on_cpu_lock, cpu)); > diff --git a/arch/x86/kvm/vmx/posted_intr.h b/arch/x86/kvm/vmx/posted_intr.h > index 7f7b2326caf5..36ae035f14aa 100644 > --- a/arch/x86/kvm/vmx/posted_intr.h > +++ b/arch/x86/kvm/vmx/posted_intr.h > @@ -40,7 +40,7 @@ static inline bool pi_test_and_clear_on(struct pi_desc *pi_desc) > (unsigned long *)&pi_desc->control); > } > > -static inline int pi_test_and_set_pir(int vector, struct pi_desc *pi_desc) > +static inline bool pi_test_and_set_pir(int vector, struct pi_desc *pi_desc) > { > return test_and_set_bit(vector, (unsigned long *)pi_desc->pir); > } > @@ -74,13 +74,13 @@ static inline void pi_clear_sn(struct pi_desc *pi_desc) > (unsigned long *)&pi_desc->control); > } > > -static inline int pi_test_on(struct pi_desc *pi_desc) > +static inline bool pi_test_on(struct pi_desc *pi_desc) > { > return test_bit(POSTED_INTR_ON, > (unsigned long *)&pi_desc->control); > } > > -static inline int pi_test_sn(struct pi_desc *pi_desc) > +static inline bool pi_test_sn(struct pi_desc *pi_desc) > { > return test_bit(POSTED_INTR_SN, > (unsigned long *)&pi_desc->control); Reviewed-by: Maxim Levitsky Best regards, Maxim Levitsky