From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [PATCH v3] KVM: Introduce direct MSI message injection for in-kernel irqchips Date: Thu, 29 Mar 2012 20:25:03 +0200 Message-ID: <4F74A8FF.5070306@siemens.com> References: <4F734EB3.20500@siemens.com> <4F748AAD.2040103@siemens.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: kvm , "Michael S. Tsirkin" , Eric Northup To: Avi Kivity , Marcelo Tosatti Return-path: Received: from david.siemens.de ([192.35.17.14]:33210 "EHLO david.siemens.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759229Ab2C2SZM (ORCPT ); Thu, 29 Mar 2012 14:25:12 -0400 In-Reply-To: <4F748AAD.2040103@siemens.com> Sender: kvm-owner@vger.kernel.org List-ID: On 2012-03-29 18:15, Jan Kiszka wrote: > Currently, MSI messages can only be injected to in-kernel irqchips by > defining a corresponding IRQ route for each message. This is not only > unhandy if the MSI messages are generated "on the fly" by user space, > IRQ routes are a limited resource that user space as to manage > carefully. > > By providing a direct injection path, we can both avoid using up limited > resources and simplify the necessary steps for user land. > > Signed-off-by: Jan Kiszka > --- > > Changes in v3: > - align return code doc to reality > - rename SET_MSI -> SIGNAL_MSI > > Documentation/virtual/kvm/api.txt | 21 +++++++++++++++++++++ > arch/x86/kvm/Kconfig | 1 + > include/linux/kvm.h | 11 +++++++++++ > virt/kvm/Kconfig | 3 +++ > virt/kvm/kvm_main.c | 21 +++++++++++++++++++++ > 5 files changed, 57 insertions(+), 0 deletions(-) > > diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt > index 81ff39f..ed27d1b 100644 > --- a/Documentation/virtual/kvm/api.txt > +++ b/Documentation/virtual/kvm/api.txt > @@ -1482,6 +1482,27 @@ See KVM_ASSIGN_DEV_IRQ for the data structure. The target device is specified > by assigned_dev_id. In the flags field, only KVM_DEV_ASSIGN_MASK_INTX is > evaluated. > > +4.61 KVM_SIGNAL_MSI > + > +Capability: KVM_CAP_SIGNAL_MSI > +Architectures: x86 > +Type: vm ioctl > +Parameters: struct kvm_msi (in) > +Returns: >0 on delivery, 0 if guest blocked the MSI, and -1 on error > + > +Directly inject a MSI message. Only valid with in-kernel irqchip that handles > +MSI messages. > + > +struct kvm_msi { > + __u32 address_lo; > + __u32 address_hi; > + __u32 data; > + __u32 flags; > + __u8 pad[16]; > +}; > + > +No flags are defined so far. The corresponding field must be 0. > + > 4.62 KVM_CREATE_SPAPR_TCE > > Capability: KVM_CAP_SPAPR_TCE > diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig > index 1a7fe86..a28f338 100644 > --- a/arch/x86/kvm/Kconfig > +++ b/arch/x86/kvm/Kconfig > @@ -36,6 +36,7 @@ config KVM > select TASKSTATS > select TASK_DELAY_ACCT > select PERF_EVENTS > + select HAVE_KVM_MSI > ---help--- > Support hosting fully virtualized guest machines using hardware > virtualization extensions. You will need a fairly recent > diff --git a/include/linux/kvm.h b/include/linux/kvm.h > index 7a9dd4b..225b452 100644 > --- a/include/linux/kvm.h > +++ b/include/linux/kvm.h > @@ -590,6 +590,7 @@ struct kvm_ppc_pvinfo { > #define KVM_CAP_SYNC_REGS 74 > #define KVM_CAP_PCI_2_3 75 > #define KVM_CAP_KVMCLOCK_CTRL 76 > +#define KVM_CAP_SIGNAL_MSI 77 > > #ifdef KVM_CAP_IRQ_ROUTING > > @@ -715,6 +716,14 @@ struct kvm_one_reg { > __u64 addr; > }; > > +struct kvm_msi { > + __u32 address_lo; > + __u32 address_hi; > + __u32 data; > + __u32 flags; > + __u8 pad[16]; > +}; > + > /* > * ioctls for VM fds > */ > @@ -789,6 +798,8 @@ struct kvm_s390_ucas_mapping { > /* Available with KVM_CAP_PCI_2_3 */ > #define KVM_ASSIGN_SET_INTX_MASK _IOW(KVMIO, 0xa4, \ > struct kvm_assigned_pci_dev) > +/* Available with KVM_CAP_SIGNAL_MSI */ > +#define KVM_SIGNAL_MSI _IOW(KVMIO, 0xa5, struct kvm_msi) > > /* > * ioctls for vcpu fds > diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig > index f63ccb0..28694f4 100644 > --- a/virt/kvm/Kconfig > +++ b/virt/kvm/Kconfig > @@ -18,3 +18,6 @@ config KVM_MMIO > > config KVM_ASYNC_PF > bool > + > +config HAVE_KVM_MSI > + bool > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index a612bc8..3aeb7ab 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -2063,6 +2063,24 @@ static long kvm_vm_ioctl(struct file *filp, > mutex_unlock(&kvm->lock); > break; > #endif > +#ifdef CONFIG_HAVE_KVM_MSI > + case KVM_SIGNAL_MSI: { > + struct kvm_kernel_irq_routing_entry route; > + struct kvm_msi msi; > + > + r = -EFAULT; > + if (copy_from_user(&msi, argp, sizeof msi)) > + goto out; > + r = -EINVAL; > + if (!irqchip_in_kernel(kvm) || msi.flags != 0) Ouch, this doesn't build if you have the proper setup. There is no arch-agnostic test for active irqchip support yet. I guess I'll refactor irqchip_in_kernel to kvm_arch_irqchip_in_kernel. Jan > + goto out; > + route.msi.address_lo = msi.address_lo; > + route.msi.address_hi = msi.address_hi; > + route.msi.data = msi.data; > + r = kvm_set_msi(&route, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1); > + break; > + } > +#endif > default: > r = kvm_arch_vm_ioctl(filp, ioctl, arg); > if (r == -ENOTTY) > @@ -2191,6 +2209,9 @@ static long kvm_dev_ioctl_check_extension_generic(long arg) > case KVM_CAP_SET_BOOT_CPU_ID: > #endif > case KVM_CAP_INTERNAL_ERROR_DATA: > +#ifdef CONFIG_HAVE_KVM_MSI > + case KVM_CAP_SIGNAL_MSI: > +#endif > return 1; > #ifdef CONFIG_HAVE_KVM_IRQCHIP > case KVM_CAP_IRQ_ROUTING: -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux