On Wed, Jun 13, 2012 at 07:01:01PM +0300, Gleb Natapov wrote: > On Wed, Jun 13, 2012 at 06:59:50PM +0300, Michael S. Tsirkin wrote: > > On Wed, Jun 13, 2012 at 04:01:24PM +0300, Gleb Natapov wrote: > > > On Mon, Jun 11, 2012 at 02:19:22PM +0300, Michael S. Tsirkin wrote: > > > > We do not want a potential broadcast to all VCPUs to run in > > > > a host IRQ handler. Implement an API that sends an MSI > > > > interrupt but only if it's safe from interrupt context, > > > > that is if it is a unicast. > > > > > > > We will still iterate over all vcpus, we may as well deliver to them. Or > > > you want to avoid a lot of vcpu kicks? > > > > This is an intermediate stage (thus RFC) for adding a cache: > > we can't cache if it's a broadcast. > > > You skipped my comment about the code bellow :)
Ouch. I missed it. Thanks for pointing out and sorry. > > > > Signed-off-by: Michael S. Tsirkin <[email protected]> > > > > --- > > > > include/linux/kvm_host.h | 2 ++ > > > > virt/kvm/irq_comm.c | 37 ++++++++++++++++++++++++++++++++----- > > > > 2 files changed, 34 insertions(+), 5 deletions(-) > > > > > > > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > > > > index c446435..ddb476a 100644 > > > > --- a/include/linux/kvm_host.h > > > > +++ b/include/linux/kvm_host.h > > > > @@ -618,6 +618,8 @@ void kvm_get_intr_delivery_bitmask(struct > > > > kvm_ioapic *ioapic, > > > > int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int > > > > level); > > > > int kvm_set_msi(struct kvm_kernel_irq_routing_entry *irq_entry, struct > > > > kvm *kvm, > > > > int irq_source_id, int level); > > > > +int kvm_set_msi_inatomic(struct kvm_kernel_irq_routing_entry > > > > *irq_entry, > > > > + struct kvm *kvm); > > > > void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned > > > > pin); > > > > void kvm_register_irq_ack_notifier(struct kvm *kvm, > > > > struct kvm_irq_ack_notifier *kian); > > > > diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c > > > > index 5afb431..3395e03 100644 > > > > --- a/virt/kvm/irq_comm.c > > > > +++ b/virt/kvm/irq_comm.c > > > > @@ -114,13 +114,20 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, > > > > struct kvm_lapic *src, > > > > return r; > > > > } > > > > > > > > -int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e, > > > > - struct kvm *kvm, int irq_source_id, int level) > > > > +static bool kvm_msi_is_multicast(unsigned dest, int dest_mode) > > > > { > > > > - struct kvm_lapic_irq irq; > > > > + if (dest_mode == 0) > > > > + /* Physical mode. */ > > > > + return dest == 0xff; > > > > + else > > > > + /* Logical mode. */ > > > > + return dest & (dest - 1); > > > > +} > > > > > > > > - if (!level) > > > > - return -1; > > > > +static int __kvm_set_msi(struct kvm_kernel_irq_routing_entry *e, > > > > + struct kvm *kvm, bool noblock) > > > > +{ > > > > + struct kvm_lapic_irq irq; > > > > > > > > trace_kvm_msi_set_irq(e->msi.address_lo, e->msi.data); > > > > > > > > @@ -134,10 +141,30 @@ int kvm_set_msi(struct > > > > kvm_kernel_irq_routing_entry *e, > > > > irq.level = 1; > > > > irq.shorthand = 0; > > > > > > > > + /* Multicast MSI doesn't really block but might take a long > > > > time. */ > > > > + if (unlikely(noblock && kvm_msi_is_multicast(irq.dest_id, > > > > + > > > > irq.delivery_mode))) > > > delivery_mode? Should be dest_mode. Yes. Good catch, thanks. > But you probably need to check that > > > delivery_mode is not ExtINT either. It does not look like anything happens with ExtInt if you try to trigger it from MSI. > > > > > > > + return -EWOULDBLOCK; > > > > + > > > > /* TODO Deal with RH bit of MSI message address */ > > > > return kvm_irq_delivery_to_apic(kvm, NULL, &irq); > > > > } > > > > > > > > +int kvm_set_msi_inatomic(struct kvm_kernel_irq_routing_entry *e, > > > > + struct kvm *kvm) > > > > +{ > > > > + return __kvm_set_msi(e, kvm, true); > > > > +} > > > > + > > > > +int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e, > > > > + struct kvm *kvm, int irq_source_id, int level) > > > > +{ > > > > + if (unlikely(!level)) > > > > + return -1; > > > > + > > > > + return __kvm_set_msi(e, kvm, false); > > > > +} > > > > + > > > > int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi) > > > > { > > > > struct kvm_kernel_irq_routing_entry route; > > > > -- > > > > MST > > > > > > > > -- > > > > To unsubscribe from this list: send the line "unsubscribe kvm" in > > > > the body of a message to [email protected] > > > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > > > > -- > > > Gleb. > > -- > Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
