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Wed, 03 Jun 2020 04:25:38 -0700 (PDT) Received: from [192.168.178.58] ([151.20.243.176]) by smtp.gmail.com with ESMTPSA id t189sm2549806wma.4.2020.06.03.04.25.37 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 03 Jun 2020 04:25:38 -0700 (PDT) Subject: Re: [bug report] KVM: x86: enable event window in inject_pending_event To: Dan Carpenter Cc: kvm@vger.kernel.org References: <20200603103415.GC1845750@mwanda> From: Paolo Bonzini Message-ID: <6c476bb5-cf85-ddb7-aaf1-0ac290bf9dfa@redhat.com> Date: Wed, 3 Jun 2020 13:25:37 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <20200603103415.GC1845750@mwanda> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 03/06/20 12:34, Dan Carpenter wrote: > Hello Paolo Bonzini, > > The patch c9d40913ac5a: "KVM: x86: enable event window in > inject_pending_event" from May 22, 2020, leads to the following > static checker warning: > > arch/x86/kvm/x86.c:10530 kvm_can_do_async_pf() > warn: signedness bug returning '(-16)' > > arch/x86/kvm/x86.c > 10516 bool kvm_can_do_async_pf(struct kvm_vcpu *vcpu) > 10517 { > 10518 if (unlikely(!lapic_in_kernel(vcpu) || > 10519 kvm_event_needs_reinjection(vcpu) || > 10520 vcpu->arch.exception.pending)) > 10521 return false; > 10522 > 10523 if (kvm_hlt_in_guest(vcpu->kvm) && !kvm_can_deliver_async_pf(vcpu)) > 10524 return false; > 10525 > 10526 /* > 10527 * If interrupts are off we cannot even use an artificial > 10528 * halt state. > 10529 */ > 10530 return kvm_arch_interrupt_allowed(vcpu); > 10531 } > > The svm_nmi_allowed() used to return false because interrupts aren't > allowed but now it returns -EBUSY so it returns true/allowed. This is intentional (i.e. not a bug) but it should have an explicit "!= 0". Paolo