On Fri, Mar 30, 2012 at 09:45:35AM +0200, Jan Kiszka wrote:
> On 2012-03-29 21:41, Michael S. Tsirkin wrote:
> > On Thu, Mar 29, 2012 at 09:14:12PM +0200, 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 has 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 <jan.kiszka@xxxxxxxxxxx>
> >> ---
> >>
> >> Changes in v4:
> >> - Fix the build by factoring out kvm_send_userspace_msi:
> >> irqchip_in_kernel is not generically available. But abstracting it
> >> for all arch is tricky and therefore left to the poor people who have
> >> to introduce non-x86 irqchip support to this x86-focused corner.
> >>
> >> Lesson (probably not) learned: Never underestimate the complexity of
> >> trivial changes.
> >>
> >> Documentation/virtual/kvm/api.txt | 21 +++++++++++++++++++++
> >> arch/x86/kvm/Kconfig | 1 +
> >> include/linux/kvm.h | 11 +++++++++++
> >> include/linux/kvm_host.h | 2 ++
> >> virt/kvm/Kconfig | 3 +++
> >> virt/kvm/irq_comm.c | 14 ++++++++++++++
> >> virt/kvm/kvm_main.c | 14 ++++++++++++++
> >> 7 files changed, 66 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/include/linux/kvm_host.h b/include/linux/kvm_host.h
> >> index 6cf158c..35c69d6 100644
> >> --- a/include/linux/kvm_host.h
> >> +++ b/include/linux/kvm_host.h
> >> @@ -774,6 +774,8 @@ int kvm_set_irq_routing(struct kvm *kvm,
> >> unsigned flags);
> >> void kvm_free_irq_routing(struct kvm *kvm);
> >>
> >> +int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi);
> >> +
> >> #else
> >>
> >> static inline void kvm_free_irq_routing(struct kvm *kvm) {}
> >> 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/irq_comm.c b/virt/kvm/irq_comm.c
> >> index 9f614b4..a6a0365 100644
> >> --- a/virt/kvm/irq_comm.c
> >> +++ b/virt/kvm/irq_comm.c
> >> @@ -138,6 +138,20 @@ int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
> >> return kvm_irq_delivery_to_apic(kvm, NULL, &irq);
> >> }
> >>
> >> +int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi)
> >> +{
> >> + struct kvm_kernel_irq_routing_entry route;
> >> +
> >> + if (!irqchip_in_kernel(kvm) || msi->flags != 0)
> >> + return -EINVAL;
> >> +
> >> + route.msi.address_lo = msi->address_lo;
> >> + route.msi.address_hi = msi->address_hi;
> >> + route.msi.data = msi->data;
> >> +
> >> + return kvm_set_msi(&route, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1);
> >> +}
> >> +
> >> /*
> >> * Return value:
> >> * < 0 Interrupt was ignored (masked or not delivered for other reasons)
> >> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> >> index a612bc8..5addfa8 100644
> >> --- a/virt/kvm/kvm_main.c
> >> +++ b/virt/kvm/kvm_main.c
> >> @@ -2063,6 +2063,17 @@ 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_msi msi;
> >> +
> >> + r = -EFAULT;
> >> + if (copy_from_user(&msi, argp, sizeof msi))
> >> + goto out;
> >
> > Wait a second, we should validate flags: you say
> > "this field should be 0" so we should check it.
>
> Yep, see kvm_send_userspace_msi.
>
> Jan
Right, missed this. Thanks.
> >
> >> + r = kvm_send_userspace_msi(kvm, &msi);
> >> + break;
> >> + }
> >> +#endif
> >> default:
> >> r = kvm_arch_vm_ioctl(filp, ioctl, arg);
> >> if (r == -ENOTTY)
> >> @@ -2191,6 +2202,9 @@ 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:
> >> --
> >> 1.7.3.4
>
> --
> Siemens AG, Corporate Technology, CT T DE IT 1
> Corporate Competence Center Embedded Linux
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