1FLIC (floating interrupt controller) 2==================================== 3 4FLIC handles floating (non per-cpu) interrupts, i.e. I/O, service and some 5machine check interruptions. All interrupts are stored in a per-vm list of 6pending interrupts. FLIC performs operations on this list. 7 8Only one FLIC instance may be instantiated. 9 10FLIC provides support to 11- add interrupts (KVM_DEV_FLIC_ENQUEUE) 12- inspect currently pending interrupts (KVM_FLIC_GET_ALL_IRQS) 13- purge all pending floating interrupts (KVM_DEV_FLIC_CLEAR_IRQS) 14- purge one pending floating I/O interrupt (KVM_DEV_FLIC_CLEAR_IO_IRQ) 15- enable/disable for the guest transparent async page faults 16- register and modify adapter interrupt sources (KVM_DEV_FLIC_ADAPTER_*) 17- modify AIS (adapter-interruption-suppression) mode state (KVM_DEV_FLIC_AISM) 18- inject adapter interrupts on a specified adapter (KVM_DEV_FLIC_AIRQ_INJECT) 19- get/set all AIS mode states (KVM_DEV_FLIC_AISM_ALL) 20 21Groups: 22 KVM_DEV_FLIC_ENQUEUE 23 Passes a buffer and length into the kernel which are then injected into 24 the list of pending interrupts. 25 attr->addr contains the pointer to the buffer and attr->attr contains 26 the length of the buffer. 27 The format of the data structure kvm_s390_irq as it is copied from userspace 28 is defined in usr/include/linux/kvm.h. 29 30 KVM_DEV_FLIC_GET_ALL_IRQS 31 Copies all floating interrupts into a buffer provided by userspace. 32 When the buffer is too small it returns -ENOMEM, which is the indication 33 for userspace to try again with a bigger buffer. 34 -ENOBUFS is returned when the allocation of a kernelspace buffer has 35 failed. 36 -EFAULT is returned when copying data to userspace failed. 37 All interrupts remain pending, i.e. are not deleted from the list of 38 currently pending interrupts. 39 attr->addr contains the userspace address of the buffer into which all 40 interrupt data will be copied. 41 attr->attr contains the size of the buffer in bytes. 42 43 KVM_DEV_FLIC_CLEAR_IRQS 44 Simply deletes all elements from the list of currently pending floating 45 interrupts. No interrupts are injected into the guest. 46 47 KVM_DEV_FLIC_CLEAR_IO_IRQ 48 Deletes one (if any) I/O interrupt for a subchannel identified by the 49 subsystem identification word passed via the buffer specified by 50 attr->addr (address) and attr->attr (length). 51 52 KVM_DEV_FLIC_APF_ENABLE 53 Enables async page faults for the guest. So in case of a major page fault 54 the host is allowed to handle this async and continues the guest. 55 56 KVM_DEV_FLIC_APF_DISABLE_WAIT 57 Disables async page faults for the guest and waits until already pending 58 async page faults are done. This is necessary to trigger a completion interrupt 59 for every init interrupt before migrating the interrupt list. 60 61 KVM_DEV_FLIC_ADAPTER_REGISTER 62 Register an I/O adapter interrupt source. Takes a kvm_s390_io_adapter 63 describing the adapter to register: 64 65struct kvm_s390_io_adapter { 66 __u32 id; 67 __u8 isc; 68 __u8 maskable; 69 __u8 swap; 70 __u8 flags; 71}; 72 73 id contains the unique id for the adapter, isc the I/O interruption subclass 74 to use, maskable whether this adapter may be masked (interrupts turned off), 75 swap whether the indicators need to be byte swapped, and flags contains 76 further characteristics of the adapter. 77 Currently defined values for 'flags' are: 78 - KVM_S390_ADAPTER_SUPPRESSIBLE: adapter is subject to AIS 79 (adapter-interrupt-suppression) facility. This flag only has an effect if 80 the AIS capability is enabled. 81 Unknown flag values are ignored. 82 83 84 KVM_DEV_FLIC_ADAPTER_MODIFY 85 Modifies attributes of an existing I/O adapter interrupt source. Takes 86 a kvm_s390_io_adapter_req specifying the adapter and the operation: 87 88struct kvm_s390_io_adapter_req { 89 __u32 id; 90 __u8 type; 91 __u8 mask; 92 __u16 pad0; 93 __u64 addr; 94}; 95 96 id specifies the adapter and type the operation. The supported operations 97 are: 98 99 KVM_S390_IO_ADAPTER_MASK 100 mask or unmask the adapter, as specified in mask 101 102 KVM_S390_IO_ADAPTER_MAP 103 perform a gmap translation for the guest address provided in addr, 104 pin a userspace page for the translated address and add it to the 105 list of mappings 106 Note: A new mapping will be created unconditionally; therefore, 107 the calling code should avoid making duplicate mappings. 108 109 KVM_S390_IO_ADAPTER_UNMAP 110 release a userspace page for the translated address specified in addr 111 from the list of mappings 112 113 KVM_DEV_FLIC_AISM 114 modify the adapter-interruption-suppression mode for a given isc if the 115 AIS capability is enabled. Takes a kvm_s390_ais_req describing: 116 117struct kvm_s390_ais_req { 118 __u8 isc; 119 __u16 mode; 120}; 121 122 isc contains the target I/O interruption subclass, mode the target 123 adapter-interruption-suppression mode. The following modes are 124 currently supported: 125 - KVM_S390_AIS_MODE_ALL: ALL-Interruptions Mode, i.e. airq injection 126 is always allowed; 127 - KVM_S390_AIS_MODE_SINGLE: SINGLE-Interruption Mode, i.e. airq 128 injection is only allowed once and the following adapter interrupts 129 will be suppressed until the mode is set again to ALL-Interruptions 130 or SINGLE-Interruption mode. 131 132 KVM_DEV_FLIC_AIRQ_INJECT 133 Inject adapter interrupts on a specified adapter. 134 attr->attr contains the unique id for the adapter, which allows for 135 adapter-specific checks and actions. 136 For adapters subject to AIS, handle the airq injection suppression for 137 an isc according to the adapter-interruption-suppression mode on condition 138 that the AIS capability is enabled. 139 140 KVM_DEV_FLIC_AISM_ALL 141 Gets or sets the adapter-interruption-suppression mode for all ISCs. Takes 142 a kvm_s390_ais_all describing: 143 144struct kvm_s390_ais_all { 145 __u8 simm; /* Single-Interruption-Mode mask */ 146 __u8 nimm; /* No-Interruption-Mode mask * 147}; 148 149 simm contains Single-Interruption-Mode mask for all ISCs, nimm contains 150 No-Interruption-Mode mask for all ISCs. Each bit in simm and nimm corresponds 151 to an ISC (MSB0 bit 0 to ISC 0 and so on). The combination of simm bit and 152 nimm bit presents AIS mode for a ISC. 153 154 KVM_DEV_FLIC_AISM_ALL is indicated by KVM_CAP_S390_AIS_MIGRATION. 155 156Note: The KVM_SET_DEVICE_ATTR/KVM_GET_DEVICE_ATTR device ioctls executed on 157FLIC with an unknown group or attribute gives the error code EINVAL (instead of 158ENXIO, as specified in the API documentation). It is not possible to conclude 159that a FLIC operation is unavailable based on the error code resulting from a 160usage attempt. 161 162Note: The KVM_DEV_FLIC_CLEAR_IO_IRQ ioctl will return EINVAL in case a zero 163schid is specified. 164