From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Auger Subject: Re: [PATCH v4 4/5] KVM: introduce kvm_arch functions for IRQ bypass Date: Mon, 10 Aug 2015 10:43:00 +0200 Message-ID: <55C86414.5070203@linaro.org> References: <1438622444-25444-1-git-send-email-eric.auger@linaro.org> <1438622444-25444-5-git-send-email-eric.auger@linaro.org> <1438978154.4023.262.camel@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: feng.wu@intel.com, kvm@vger.kernel.org, patches@linaro.org, marc.zyngier@arm.com, joro@8bytes.org, mtosatti@redhat.com, linux-kernel@vger.kernel.org, avi.kivity@gmail.com, pbonzini@redhat.com, eric.auger@st.com, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org To: Alex Williamson Return-path: In-Reply-To: <1438978154.4023.262.camel@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu List-Id: kvm.vger.kernel.org On 08/07/2015 10:09 PM, Alex Williamson wrote: > On Mon, 2015-08-03 at 19:20 +0200, Eric Auger wrote: >> This patch introduces >> - kvm_arch_irq_bypass_add_producer >> - kvm_arch_irq_bypass_del_producer >> - kvm_arch_irq_bypass_stop >> - kvm_arch_irq_bypass_start >> >> They make possible to specialize the KVM IRQ bypass consumer in >> case CONFIG_KVM_HAVE_IRQ_BYPASS is set. >> >> Signed-off-by: Eric Auger >> Signed-off-by: Feng Wu >> >> --- >> >> v2 -> v3 (Feng Wu): >> - use 'kvm_arch_irq_bypass_start' instead of 'kvm_arch_irq_bypass_resume' >> - Remove 'kvm_arch_irq_bypass_update', which is not needed to be >> a irqbypass callback per Alex's comments. >> - Make kvm_arch_irq_bypass_add_producer return 'int' >> >> v1 -> v2: >> - use CONFIG_KVM_HAVE_IRQ_BYPASS instead CONFIG_IRQ_BYPASS_MANAGER >> - rename all functions according to Paolo's proposal >> - add kvm_arch_irq_bypass_update according to Feng's need >> --- >> include/linux/kvm_host.h | 33 +++++++++++++++++++++++++++++++++ >> virt/kvm/Kconfig | 3 +++ >> 2 files changed, 36 insertions(+) >> >> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h >> index 05e99b8..84b5feb 100644 >> --- a/include/linux/kvm_host.h >> +++ b/include/linux/kvm_host.h >> @@ -24,6 +24,7 @@ >> #include >> #include >> #include >> +#include >> #include >> >> #include >> @@ -1151,5 +1152,37 @@ static inline void kvm_vcpu_set_dy_eligible(struct kvm_vcpu *vcpu, bool val) >> { >> } >> #endif /* CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT */ >> + >> +#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS >> + >> +int kvm_arch_irq_bypass_add_producer(struct irq_bypass_consumer *, >> + struct irq_bypass_producer *); >> +void kvm_arch_irq_bypass_del_producer(struct irq_bypass_consumer *, >> + struct irq_bypass_producer *); >> +void kvm_arch_irq_bypass_stop(struct irq_bypass_consumer *); >> +void kvm_arch_irq_bypass_start(struct irq_bypass_consumer *); >> + >> +#else > > Do we really need static inline stubs? When would they get used? This addresses the case where another arch would use an irq bypass producer (such as vfio platform driver ) and irqfd without implementing/needing forwarding/posting stuff. I see 2 solutions: either we have those stubs or in eventfd.c we guard irq_bypass_unregister_consumer(&irqfd->consumer); and ret = irq_bypass_register_consumer(&irqfd->consumer); by #ifdef CONFIG_HAVE_KVM_IRQ_BYPASS #endif This latter solution maybe is better. How > would they work since we call them via function pointers? Just tested that without the ARM forwarding implementation of kvm_arch functions and that runs fine. > >> + >> +static inline int kvm_arch_irq_bypass_add_producer( >> + struct irq_bypass_consumer *cons, >> + struct irq_bypass_producer *prod) >> +{ >> + return -1; > > No reason not to stick with standard errno values, is there? -EINVAL > Thanks, sure Thanks Eric > > Alex > >> +} >> +static inline void kvm_arch_irq_bypass_del_producer( >> + struct irq_bypass_consumer *cons, >> + struct irq_bypass_producer *prod) >> +{ >> +} >> +static inline void kvm_arch_irq_bypass_stop( >> + struct irq_bypass_consumer *cons) >> +{ >> +} >> +static inline void kvm_arch_irq_bypass_start( >> + struct irq_bypass_consumer *cons) >> +{ >> +} >> +#endif /* CONFIG_HAVE_KVM_IRQ_BYPASS */ >> #endif >> >> diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig >> index e2c876d..9f8014d 100644 >> --- a/virt/kvm/Kconfig >> +++ b/virt/kvm/Kconfig >> @@ -47,3 +47,6 @@ config KVM_GENERIC_DIRTYLOG_READ_PROTECT >> config KVM_COMPAT >> def_bool y >> depends on COMPAT && !S390 >> + >> +config HAVE_KVM_IRQ_BYPASS >> + bool > > >